Monday, April 28, 2014

Self Defense Tactics: Is Tactile or Audible Trigger Reset Important?

One of the complaints I hear a lot about some pistols such as the Browning Hi-Power and the Remington R51 is that there is no perceivable trigger reset. Trigger reset on a firearm is the point where, after firing a shot, the trigger is reconnected to the sear and ready for the next shot. Some firearms have a trigger reset, some do not. Single shot firearms do not. Fully automatic firearms do but it is somewhat irrelevant. Single action revolvers do not, double action revolvers do. All semi-auto firearms have a trigger reset. Generally, this reset occurs before the trigger has returned fully forward to a rest position. In some pistols, the reset can be heard by a slight click, or felt by the trigger finger.

Somewhere in the course of speed related competitions over the last 30 years or so, someone developed the technique of "firing from the reset". This involves pulling the trigger immediately upon detecting the reset without allowing the trigger to fully complete the return. It can gain a fraction of a second in split times between shots. 

The technique works with some guns but not with others. The Browning Hi-Power and Remington R51 already mentioned have no detectible reset short of full return. The 1911 may or may not have one depending on how it is tuned. Most double-action revolvers, and pistols have detectable reset well short of full return, as do many striker fired pistols such as Glocks and S&Ws.

This technique is especially suited to Glocks because the Glock has a distinctly detectable trigger reset. Many Self Defense instructors teach the technique. It is no coincidence that many SD instructors are Glock oriented. And students love it because it seems like one of those secret tricks the pros use that make the seem better than the average shooter. The advantage from faster split times can be demonstrated at the range, and in different formal competitions, but how useful is shooting from the reset in a real self defense situation?

It is well accepted that for most people, a self defense situation is a high stress situation, often accompanied by an adrenaline dump as the body responds with the fight or flight reflex. One of the results of an adrenaline dumb is the loss of fine motor skills. And it is fine motor skills that allow the detection and response to a tactile trigger reset. Another result is a suppression of audio sensation, which means that an audible reset is going to be undetectable as well. So for most people, in a SD situation, a detectable trigger reset is a moot point. They won't be able to detect it, much less respond to it.

Couple this with the fact that under high stress, one tends to revert to the training. Repetitive training develops muscle memory and reactions that become almost instinctive. If one has trained to wait for a trigger reset before firing a second shot, and that reset is rendered undetectable, the result may be a slower second shot, instead of a faster one.

Granted, there are a few people who may not experience an adrenaline dump when their life is in danger, but they are rare. For most people, the adrenaline dump will happen, fine motor skills will be lost and the idea of using tactile reset in a SD situation is just a delusion. To each his own, but practicing techniques that depend on a skill that may well be unavailable when needed is not something I see any advantage in doing.

Sunday, April 27, 2014

Remington R51: First Look Inside Out

barnbwt, who frequents The High Road forums, has detail stripped his Remington R51. You can read about it in this thread on The High Road.

R51 Inside Out (image by barnbwt)

He alao ran a finish reamer into the chamber with interesting results. He describes that n the same thread. The finish reamer took out enough metal to confirm our hypothesis that the chamber is severly undersized. The chambering is more like "9mm Remington (a previously unknown chambering) than 9mm Luger as marked.

Saturday, April 26, 2014

Remington R51: Rumors and Responses

I called Remington Customer Service to see if they had anything to offer on the problems I found with the chamber of my R51 and its failure to chamber some factory ammo other than Remington. I had also lost a pin (since found) and inquired about a replacement (no spare parts available). He was having trouble getting my info entered in his database and the conversation went something like this:
REM CS: "Sorry for the delay, the system is acting up."
Me: "Been there"
REM CS: "We paid a lot of money for this, you'd expect it to work."
Me: Yeah, a lot people think that about their guns,
REM CS: [long pause] Oh! right.
Anyway, he wasn't interested in talking about the chamber, but did get interested when I mentioned the "pimpled" primers. Said that was caused by firing out of battery and I needed to send in the gun. Which brings me to this:

A post on GlockTalk says that a Remington rep at the NRA convention disclosed that they had found problems with slides being "out of spec" and not interfacing with the breechblock properly causing the out of battery problems being reported. (I suspect it could also cause the loose sight problems as well) The post goes on to say that engineers are on site, production has been halted, and the Para plant has been shut down until the problem has been resolved, perhaps late May or early June. This suggests there may be a recall in the future for guns already released.

An out of tolerance slide could cause a lot of problems, if it allows the breechblock to move too much when it is supposed to be in battery. Fixing this is imperative, but it still doesn't address the problems with the chamber not allowing rounds to fully chamber. In fact, fixing the slide could aggravate this problem as there might be no play in the breechblock to accommodate the not fully chambered round, causing even more out of battery conditions.

This post on the Remington Owners Forum says the breechblocks are being modified and the slides are being replaced to deal with loose sight issues.

There is also a rumor that Remington is reworking the firing pin in some way to address the primer flow pimples.

 Remington has sent me an RMA packet, but since my gun seems to be less problematic than most except for the chamber which I can work around by being careful of the ammo I use, I think I will wait until there is more clarity to send it in. I don't want to sit without the gun for 2 months when I could be shooting it.

Monday, April 21, 2014

A modest proposal to apply to the 1st Amendment, regulations equivalent to those proposed for the 2nd

What if the rights protected by the 1st Amendment were subject to the same restrictions as the rights protected by the 2nd?

1 The manufacture, importation, transfer and use of All high speed presses is hereby banned. In addition, specific presses to be listed later are banned.

2. No publication may contain more than 10 pages. No sentence, either spoken or in print, may contain more than ten words or words of more than two syllables (oops).

3. All cameras, smart phones, digital tablets and personal computers must be registered with the govt. within 90 days.

4. No one, other than government officials, may access the internet as speeds higher than 56kbs (AKA a "dial-up" connection).

5. Everyone residing in or entering the USA will be voiceprinted, said voice print to be maintained in a national data base so that a person uttering offensive speech may be easily identified. Anyone subsequently found without a voiceprint on file will have their vocal cords removed and forever loose their right to speak.

6. Any property, private or public, may be designated as no speech zones. Anyone entering such zones will have their mouths duct-taped to prevent disallowed speech.

7, Conversation between private individuals is not allowed. All conversation must take place in a government licensed location where the conversation can be monitored and recorded. All conversation must be face-to-face after presentation of proper ID verified by voiceprint analysis. No words or pictures may be exchanged electronically or by mail.

8. Religious practices shall be limited to specified places of worship (list of approved places to follow). No religious services may be held in a facility that does not have an exterior appearance common to approved places of worship.

Friday, April 18, 2014

Remington R51: Is it safe?

There are numerous articles and videos out there in which the safety of the R51 is questioned, on the basis of design and/or functioning. Here is one example.

Perceptions are hard to overcome, and there is a lot of misunderstanding about the difference between in battery and locked breech contributing to negative perceptions.

To be clear, when a firearm is in battery, the bolt is fully closed. This usually means the breechblock/bolt is in contact with the breech face, and if a round is in the gun, it is fully chambered and properly headspaced (headspace is the distance measured from the part of the chamber that stops forward motion of the cartridge (the datum reference) to the face of the bolt. This distance is part of the cartridge specification).

The breech is locked when the breech can not be opened or moved by direct pressure from the head of the cartridge case. On most firearms, this is coincident with the firearm being in battery.

What the linked article fails to explain fully is that unlike other systems that lock the breech when in battery—such that in battery and locked breech are almost synonymous, the Pedersen delayed lock only locks the breech when the firearm is out of battery.

The short distance the bolt/breechblock travels between battery and lock imparts the momentum to the slide which is necessary to unlock the bolt once it locks. Firing from an out of battery, fully locked breech position will not cycle the slide. Any thing less than fully locked may or may cycle the slide or may short cycle it.

Every out of battery condition I have seen on my gun is due to the apparent failure to finish ream the chamber to SAMMI specs. This leaves the chamber with no throat and without a throat, there is a lot of ammo that will headspace off the bullet on the lands instead of the case mouth. This creates the out of battery condition.

When the slide is out of battery with the breech locked, it is not possible to cycle the action through pressure on the bolt. It is also almost impossible to detect this condition looking at the ejection port. One must look at the muzzle, (from the side please) to see if and how far the muzzle extends past the slide. It will be flush when fully in battery.

Also note that when the slide is out of battery enough to unlock the bolt, the hammer will not strike the firing pin with enough force to ignite the primer. (I've been trying to make this happen with no success).

I have seen numerous reports involving failures to feed, cycle, eject, etc. and examples of bulged cases and primers. 

The bulged case pictured in the linked article appears to be bulged on one side only. Close inspection of the barrel with a chambered case shows that the rim and extractor groove of the case head extends past the breech face and is unsupported by the chamber walls. This is not a problem because the case head is solid brass.

Fully chambered case


When the case is extracted far enough for the bolt to lock, the exposed portion of the case is still solid brass and the thinner case walls are still supported by the chamber walls. Except for a small spot just above the feed ramp. This is where I believe the bulge is occurring. It is very similar to the infamous Glock bulge in .40 cal Glocks.

Case when out of battery


When a cartridge is headspaced off of the bullet on the lands, the bullet may be tightly engraved on the rifling. This condition causes an unsafe pressure spike when the gun is fired because more pressure than normal is needed to start the bullet in motion. Pressure is exerted in all directions, and will follow the path of least resistance. Until the bullet starts moving, the point of least resistance is the unsupported case wall above the feed ramp. So it bulges. If the bullet fails to move the case will probably rupture, but it would probably take a cartridge loaded seriously out of spec to create this condition and such a cartridge could cause a problem in any gun.

I have yet to see any report of a catastrophic failure such as a ruptured case or pierced primer, which would indicate that the bullet started to move a pressures dropped to safe levels before a rupture occurred.

IMO, (which is worth whatever you think) the gun is safe to fire in and out of battery with commercial ammo and safely loaded hand loads, but until the chamber is cut to SAMMI spec, is not functionally reliable with all ammunition.

Remington R51 Summary and Opinion

After 200+ rounds, I'm only half way through break in, but I have made a few discoveries and formed an opinion. As with all opinions, it is subject to change as new facts develop.

The gun design is solid and so is the gun if made properly. Remington recently absorbed Para-USA (formerly Para Ordinance) and the gun is built by Para in Clintonville, NC. I don't know, but it appears they might have laid off the Quality Control department. Remington is taking a lot of guns back for warranty work (which may explain why there are no spare parts for sale) but turn around is a couple of weeks or more. Some of these problems are probably resolvable by tech-savvy owners willing to tear into the gun so if you like living on the bleeding edge, go for it. If not waiting until the production problems are resolved may be your best bet. But waiting is not the same as giving up. If you need a very accurate, controllable, concealable, 9mm+P rated gun for home or self defense, this is a gun worth waiting for.

At the price, I didn't have high expectations of quality, I just expected the gun to function, and perhaps need some tweaking to function reliably. The gun I have meets those expectations. The only major problem I have right now is the chamber/barrel, and I can fix that myself if Remington does not.

I still suspect the possibility of apathy at Para towards producing this gun resulting in careless production and QA. If they can get that under control, firm up the trigger wobble (which just screams CHEAP even when it causes no functional problem), and cut a proper chamber they will clear up a lot of the problems people are having IMO.

Another thing, Remington "introduced" the R51 at surprise session for writers at Gunsite in Dec. 2013. The guns there were pre-production models and the writers burned through a few thousand rounds of ammo and raved about the pistol. These demo guns had solid, not skeletonized, triggers and there as no mention of side wobble. Also, the slides were very easy to rack. MSRP was estimated at $375 with a mid Feb release

When SHOT 2014 rolled around a moth later, there were guns at the Remington booth, but the trigger had changed to a skeletonized version. And the gun was not available for shooting on media day. This sent up red flags. MSRP was now $420 another flag. Mid Feb came and went without guns, yet another flag. When the gun started hitting the stores in March, it was different beast than the writers saw at GunSite.

I think there was some hard pressure to cut costs, maybe to get to the $375 MSRP level, may just to increase the profit margin. the cost cutting was done in little things. A cast skeletonized trigger saved metal and machine time. But it also lost some precision and gained some side play. Longer machine runs before changing tools may have saved a little on production cost, but added rough finish. marks in places and poor tolerances. The barrels were rough chambered and not finish reamed of polished, QA inspections were reduced and rejections limited. More guns reached the shelves in conditions that should never have made it out the door. The preceeding is just wild speculation but it does make some sense.

These are the only issues I have with mine in what I consider order of seriousness:

1. Firing pin sticks in channel resulting in light strikes and failure to fire.

 Serious because of difficulty of recovery during fire. Cycling may or may not jar pin loose. Could be a fatal malfunction in an SD situation.

The firing pin (at least mine did) has burrs around the cut for the retaining pin. Quick polish with 1200 grit emery paper removes the burrs and eliminates problem.

2. Chamber not finished.

Most problems reported seem to stem from failure to fully chamber some brands of ammo as a result of no throat being cut to allow the cartridge to chamber without the bullet contacting the lands.
   
Needs to be finished reamed. This requires a gunsmith or factory service. I can do it myself, but I don't want to have to.    

3. Slide action is erratic. Sometimes it is harder to rack then others 

This problem is deeper than it might seem. The source of the problem seems to be in the disconnector, which is engaged at 3 distinct times during the cycling. The slide is easiest to cycle when the pistol is not cocked and the trigger and safety are both held down while cycling the slide. If the trigger is not held down, the disconnector offers stiff resistance right at the beginning of the cycle when slide momentum can't assist in defeating it.

There are several points during the cycle of the slide that the trigger is not disconnected and can be pulled, tripping the sear and releasing the hammer. Pulling the trigger while the slide is cycling (perhaps in anticipation or trigger reset?) can depending just when it occurs, result in the hammer falling to half cock and locking the slide partially open.

The disconnector needs to be redesigned so that it is activated just after the breech unlocks and ideally, does not reconnect until the pistol goes into battery. This would prevent the pistol from firing out of battery (with the breech locked) and insures the pistol con only be fired when there can be enough momentum imparted to the slide to cycle the action.
   
Finish polish/deburring of the recoil spring bushing, and channel in the slide in which it rides will help as well.    

4. Trigger side wobble

The trigger wobbles from side to side, sometime binding in the channel

A problem for some because if excessive, can cause the trigger to hang up on sides of the trigger channel in the frame.
   
A bushing that could also serve as an assembly slave pin would correct a of to this, as would widening the trigger to lengthen the pin hole.   

5. Magazine issues

Hollow points hang on the front lip of the magazine.

The magazine is overly long, front to back for 9mm. This is because it fits the mad well and it is oversized, probably to accommodate multiple calibers in the same frame. The front feed lip seems to serve the purpose of guiding shorter rounds back into the feed lips just before they are picked up by the slide. I think this is necessary to get the rim under the extractor, so removing the front lip is not really an option. Perhaps it can be made wider so it can't enter the wider hollow points, or perhaps a full length spacer can be pressed into the sheet metal.
   
Base plate recessed into frame makes mag difficult to seat reliably. Also makes it hard to remove if jammed.

Remington need to offer extended base plates.If they don't, someone probably will if the gun sells.
   
Followers sometimes stick   
Dry silicone lube helps. A Teflon follower would help more.

Other complaints I consider non-issues

Slide bite
The really high grip adopted by many shooters in an attempt to lower the bore axis of other guns is not needed with the R51 as the bore is already 25% lower. The high grip lets the web of the hand "flow" over the grip tang where it is exposed to the slide when cycling.
   
A high thumbs forward grip can expose the strong hand thumb to the slide edges. The R51 slide rides outside the frame, not inside, so a high thumb is not protected by the frame. The cocking serrations can act like a cheese grater on a high thumb
       
Shooters need to learn how to grip the pistol.
   
Grip Safety hard to engage
A thumbs forward grip generally employs side to side tension, rather than front to back tension. It is entirely possible to grip the gun thumbs forward without disengaging the grip safety unless a conscious effort is made to do so.
   
Once again, shooters need to learn how to grip the pistol.
   
Mag release hard to access
Makes it hard to drop a magazine.
   
It is an ambidextrous mag release. It can be accessed by the trigger finger or either thumb. Figure out which works best and use it. Practice it. Most shooters have developed muscle memory for other guns, not this one. This is a different gun. Don't expect it to be exactly the same as something else. Wait a bit and someone will offer an extended/oversized mag release that will cause other problems.
   
Grips are too flat
Yes they are. It is part of what makes the gun so slim. But I'm sure someone will be making custom grip panels, or you can make your own. I think a maroon linen micarta would be nice.
   
Sights hard to see.
What? These are perhaps the most visible stock sights on any gun of this type. Granted, they are not night sights and are hard to see in the dark. But like the grip panels, someone will be making after market sights. Crimson Trace already makes a laser ($199 at Midway).
   
Now we wait and see what Remington decides to do.

Remington R51: Range Report

Break in

I'm told that Remington Customer Service suggests a 200–400 round break in period (this is not mentioned in the Owner's Manual. YouTube reviewers/detractors didn't bother with that, some even stated their opinion that a gun should work first time out of the box. regardless of what the manufacturer says and went straight to the range without an initial cleaning and lubrication. They are wrong. Unless a manufacturer specifically makes that claim, it should not be expected, amd even if the claim is made, I will always clean and lube a new gun just to make sure there are no metal savings left from manufacturing that can screw things up. 

The manual states at the bottom of page 14 that the gun is designed for use with Remington or Barnes brand ammo and Remington is not resposible for the results of using any other ammo. Since all of the failures to chamber so far have been with other brands, this might be something to keep in mind, but with erratic ammo supplies, many shooters just have to shoot what they can get.

So lets get started.

Range Report

At the range I had a few problems with a magazine as noted below. Otherwise the gun ran fine. It is soft shooting and recoil is very controllable for a gun of this size and weight—almost as good as my HighPower. Accuracy is good. I can hold 2" at 10 yards if I really try. (I may do better after my next cataract surgery.) 115g shoots low, 124g is dead on. The target on the left is the R51 7 yards, 21 rounds firing as fast as I could. The target on the right is 39 rounds rapid fire from my BHP, same distance.



Total round fired: 214
  • 50 rounds Rem-UMC 124g FMJ: 2 FTF. These rounds all pass the plunk test
  • 50 rounds Fed American Eagle 115g: 3 FTF, 1 FTE. Plunk OK lands engrave slightly.
  • 100 rounds MBC 9Cone 125g /4g W231: 4 FTF, COL 1.090 Plunk PASS.
  • 14 rounds MBC 9Cone 124g /5.6g PowerPistol: 5 FTF 2 FTE, COL. 1.125 Plunk FAIL, lands heavily engraved. These are low pressure loads.
NOTE: FTF = Fail To Feed, FTE = Fail To Extract/Eject. Plunk test: PASS: a round dropped into the chamber will fall out easily.

All FTFs in the first 200 rounds were with the same magazine. I'll have to take a look at that one. The other mag was fine except on the last 14 rounds where it had two of the FTFs. All of the FTFs took the same form, with the bullet nosediving into the feed ramp. A sharp rap on the butt of the magazine cause all but two to feed. On these two, I had to drop the mag as the nose of the bullet was caught under the front lip of the mag. Both of these were with the Fed AE.

The cases all show the scuff marks from the rough chamber walls that seem to be a signature of this pistol. The primers of the first 200 rounds were normal except for a "pimple with a dimple" where the metal fire formed around the firing pin and firing pin hole.



On the 14 +P loads, the dimple was gone and the pimple somewhat flattened. There were no bulged primers or bulged cases.

On cleaning, I saw nothing out of the ordinary. I found no metal shavings and only one new wear mark on the frame.



Grip screws and sights stayed tight and in place, as did all of the pins. Some dry silicone lube seems to have cured the sticky mag but a Teflon follower would be more permanent.

All in all, Except for the way the chamber is cut, I'm happy. After another 200 rounds or so, I expect it ro run even smoother.

Thursday, April 17, 2014

Remington R51: A look at the Pedersen Action

As noted earlier, the R51 utilizes the Pedersen delayed lock impeded-blowback system. There are several things that shooters familiar with the Browning tilting barrel action found in the 1911, Browning High-Power  and many other semi-auto pistols will find very different, even disconcerting.

In most locked breech firearms, when the arm is in battery, the breech is locked. With the Pedersen action, when the breech is locked, the firearm is out of battery. When in battery, the breech is unlocked. It works as follows:


  • When the gun is fired, chamber pressure drives the case into the breech block which, along with the slide, is driven backwards until the breech block is stopped by the stop in the frame. Note that when the gun is fired, the breech is not locked even though the gun is in battery.
  • The breech block stops and locks the breech while the slide continues to the rear, This delayed lock is the key to the impeded blowback system. The case is partially out of the chamber about .10 of an inch) so the chamber remains sealed unto the bullet leaves the barrel and pressure drops.
  • After pressure drops. A lug on the slide cams the front of the bolt down lifting the rear over the block in the frame allowing the slide and bolt to continue together as the case is extracted and ejected.

That's the way it works in theory, in practice, sometimes not so much. There can be problems and the R51 has some.

Headspace/Firing Out of Battery (FOOB)/Fail to Return To Battery (FRTB)

I've seen reports and several videos of failure to return to battery and firing out of battery. Before going to the range, I looked into this.

Most FRTBs were reported on the first round from the mag. I loaded up a mag of dummy rounds I made up using MBC 9Cone and the only way the first round created a FRTB was if I rode the slide down. Slingshoting (pulling the slide all the way back and letting it drop) chambered the rounds every time. So, I decided to test further with other rounds. I had some other dummies made up for plunk testing my High-Power. These would not fully chamber. In fact, the bullet was jammed on the lands with the slide clearly out of battery. So badly jammed that I had to put the rear sight on the end of a piece of 2x4 and lean on it to eject the round. It ejected the case leaving the bullet stuck in the barrel and I had to tap it out with a rod.

I then plunked an empty case, a Federal 115g FMJ, and a Remington 147g Golden Sabre and an older dummy with a different lead cone bullet. and took measurements.

Except for  the initial dummies which I had intentionally seated deep and the empty case, all failed to fully chamber, and the bullets had clearly engraved on the lands. The number below reflect the among of case exposed when chambered and the amount in excess of the empty case.

    Empty Case:                0.120 (0.000) (COL: 0.754)
    9Cone Dummy #1:      0.120 (0.000) (COL: 1.060)
    9COne Dummy #2:     0.186 (0.066) (COL: 1.149)
    Lead Cone Dummy:    0.150 (0.030)
    Federal AE FMJ:         0.141 (0.021) (COL: 1.151)
    Rem Golden Sabre      0.124 (0.004) (COL: 1.148)
    Win SilverTip              0.120 (0.000)
    Rem UMC:                  0.120 (0.000) (COL: 1.105
    Blazer FMJ:                 0.141 (0.021) (COL: 1.151)

Having the bullets deeply engraved in the lands is going to raise pressures. and if the gun is out of battery as well, it is not a good situation. Before I go to the range, I may load up some minimum loads of varying OALs.

Obviously I am going to have to seat deeper when reloading for the R51 than I have been doing for my HiPower. And I think the bullet diameter and shape and OAL of factory loads may be critical. In one of the vids, from either RyeonHam or Tactical Existence, he had FOOBs and FRTBs with Cor-Bon and Speer Gold Dots but no problems with Remington FMJ. Somehow, I have the feeling that Remington's new Ultimate Defense will work as well.

I slugged the barrel (since I already had bullet stuck in it) with the following results:

    Slug diameter:     0.3565
    Lands:                  0.3460
    Grooves:              0.3560

Diameter of bullets tested:

    9 Cone:             0.3565
    FedFMJ:           0.3550
    Rem GS:           0.3470
    Win ST:            0.3510
    REMUMC:      0.3510
    Blazer :             0.3550
   
The Rem Golden Sabre, Remington-UMC FMJ and Winchester Silvertip are apparently close enough to the land diameter that they do not jam on the lands before fully chambering. The lead 9Cone and the Federal AE FMJ are closer to the groove diameter so they do jam on the lands.

I have seen reports online of Cor-Bon and Speer Gold Dot failing to fully chamber, and Remington FMJ chambering properly. I have seen no reports of bulged cases or bulging primers confirmed to be associated with fully chambered rounds.

Standard Case length of a 9mm is .0754". The rim and rebate (extractor groove) is 0.117" That leaves 0.637" for the body of the case. I measured the chamber depth at 0.635 +/- 0.0005" If it is short, is by 0.0015" and my measurement could easily be off that much.

Since this is a delayed-lock blowback system, the case is moving out of the chamber while still under pressure, but because of the delay, it doesn't move far enough to expose the brass walls before the pressure drops, if the round is fully chambered and the slide is in battery when fired.

The chamber design leaves the case head unsupported, but it is solid brass so it really doesn't matter. There is a small area of the body unsupported at the feed ramp. Very similar to a .40S&W Glock. This probably isn't a problem unless the gun fires out of battery which it can do of the round isn't fully chambered, Then the case might be bulged at that point.

The chamber is reamed very closely to spec. Cases fire formed to my BHP will not chamber at all in the R51. As noted, there is no leade or "throat" so where the chamber ends the rifling begins. A cartridge is going to headspace on either the chamber shoulder or the lands. The chamber walls are rough, almost a matte look, and feel like 1000 grit emery. When a case is fired, the walls tend to grip it tightly and when pressure drops, there is very little relaxation so the case is still held fairly tightly.

The angle of the breech block is 4 degrees off of the horizontal bore axis. The breech block face lugs (that contact the barrel) form an 86 degree angle with the top of the breech block, as does the breech block face itself. So the case head and breech block face are perpendicular to the bore and parallel to each other. But their is at least 0..08"-0.10" between the extractor claw and the breech block face (twice the 0.050" rim thickness) which allows the case to feed, but also allows the firing pin to push the case and primer away from the breech block face at ignition. That probably contributes to the primer anomalies.

Factor in the rough chamber walls that tend to grip the case, and it is easy to see what happens when a cartridge is fired. Lets look at the action in a little more detail, focusing on what is happening in the chamber.

When the slide is in battery with a round chambered, the head of the case is under the extractor which holds it loosely against the breech block face. The lug of the breech block face is flush against the barrel, and he breech block is below a recess in the slide with its rear face against a lug in the slide. There is about 0.10" of space under the extractor for a 0.05" rim.

  1. When the trigger is pulled, the hammer falls and strikes the firing pin.
  2. Because of the space under the extractor, the firing pin pushes the breech block away from the case creating a slight gap (0.050") between the case head and the breech block face while the primer is still in contact with the firing pin.
  3. Primer ignition presses the primer against the firing pin and primer deformation begins.
  4. Powder ignition expands the case walls, and pressure drives the bullet forward and with the case firmly held by the rough walls, drives the primer backward. (If the case is not fully chambered due to a bullet headspacing off the lands, or failure of the operator to slingshot the slide, the unsupported portion of the case wall exposed above the feed ramp will likely bulge at this point)
  5. The primer swells, may be pushed out of the pocket until it contacts the breech block face where it stops and transfers its motion to the breech block and slide which start to move rearward. If the firing pin is still in contact with the primer, the primer may flow around the pin at this point and into the FP hole in the breech block.
  6. Pressure should have reached the point that the case is being driven rearward, but if the walls are too right and the chamber too tight, and the pressure curve too sharp, the case may separate at this point. Either way, the case head strikes the breech block face and drives it against the breech block stop on the frame. This stops the breech block and lock the breech while allowing the slide to continue unabated. If the gun was in batter y when fired, the breech has been locked and sealed with the case walls fully supported (except for the small area above the feed ramp) until this point.
  7. About this time, the bullet leaves the barrel, pressures drop and lug on the top of the slide contacts  a lug on the top front of the breech block and cams it down, which cams the rear of the breech block up off of the frame. The lug on top of the breech block fits into a recess in the top of the slide which allows the slide to pull the breech block backward as it continues its momentum while the extractor extracts the case until it hits the ejector and is ejected.

The primer is going to absorb a lot of pressure in this system, and harder primers will almost certainly hold up better than thin soft ones. I think I will avoid Federal primers when reloading, but still, there have been lots of reports of primer deformation, but none (that I have seen) of primer perforation. Fortunately, primers are a one use item and whatever abuse they absorbed they take with them. But, a redesign of the firing pin might help here. The pin is tapered so the hole in the breech face may be larger than it needs to be.

Another result of locking the breech out of battery, is that the case may fail to extract. If you take an unloaded R51 and put a dowel down the barrel and push on the breech, you can push it into lock up. But you can move it no further no matter how hard you push. It just locks tighter. This is because the movement of the slide against the lug on top of the block is what cams it out of lock. And in the proper firing sequence, it is the short movement of the block from battery to lock that gives the slide the necessary momentum to then cam the block out of lock. Start out of battery and locked, and there is no momentum imparted to either the block or the slide, so there is the slide does not even cycle.

This action functions very differently from the 1911 and appears to break many of the rules of safe function. The initial reaction of many is that the design is flawed and unsafe. In fact, it is neither.

Next post: The Range

Wednesday, April 16, 2014

Remington R51: The gun everyone loves to hate. But WHY?



The Remington R51 is here (actually I have had it for over a week). This is an new gun utilizing an action design not seen in handguns for nearly 100 years. The R51 uses an impeded or delayed lock blowback action designed by John D. Pedersen, that was last seen in a handgun in the Remington 51 produced between 1918–1927. The Model 51 was chambered in .32ACP and .380ACP. A Model 53 in .45ACP was submitted for Army trials and from all reports, actually performed better than the 1911, but Remington could not produce the numbers required. The R51 is chambered in 9mm Luger (or Parabellum) and is rated for +P ammo. It is a single stack with 8 round (7+1) capacity. The gun is targeted for the concealded carry, personal defense market.

The release of the gun prompted the usual rush of reviewers trying to see who could demonstrate the most problems in YouTube videos. It became the gun everybody loved to hate. I was not one of them for two reason: I could not find an R51 for several weeks and when I did, I had very few problems.

As my search dragged on, I watched the videos and read the online forum reports and had second thoughts. Bulging primers, bulged cases, metal shavings in the action, rifling shooting out of the barrel, stuck safety, jammed slides, failure to fire, failure to feed, failure to eject, and total lockups, along with loose sights and assorted loose pins and screws. Some reviewers giddily proclaimed its demise, others just recommended waiting for the second or third production run when the problems had been resolved.

But I have been a software beta tester and am not afraid to live of the bleeding edge of technology. Someone has to do it or there won't be enough sales to warrant a 2nd production run. So when I found one at a local Academy store, I grabbed it.

Speaking of software, there is no warranty card in the box, warranty registration is on line. Only problem is, the R51 is not listed in any of the drop down lists. The online form will accept all of the informatuon requested, and clicking "SUBMIT" produced no error so I think my warranty is registered. Apparently Remington's  website gurus are off working on healthcare.gov.

 Dimensions

  •  Weight w/empty mag; 22.3 OZ.
    Weight w/o mag: 20.6 oz.

    Width:  25.4mm / 1.00"
    Length (Diagonal dimension-base of grip to muzzle): 202mm / 7.95"
    Length (straigt line Muzzle to base of grip line): 175mm / 6.89
    Length (Muzzle to end of slide):    172mm / 6.77"
    Height (base of grip to top of sight): 116mm / 4.57"
    Mag well width: 15.4mm / 0.606"
    Mag well length: 36.9mm / 1.45"
    Magazine width: 15.1mm / 0.59
    Magazine length: 33.2 / 1.31"
    Grip Height BackStrap: 78.9 / 3.10"
    Grip Height FrontStrap: 63.5mm / 2.50"
    Grip Length: 52mm / 2.05"
    Grip Width: 25mm / 0.98"
    Pull: 75.2mm / 2.96"
    Front of Trigger Guard to Muzzle: 45mm / 1.77"
    Inside Trigger Guard Height: 23.7mm / 0.93"
    Inside Trigger Guard trigger to front: 25.3mm / 0.996"
    Barrel (breech face to muzzle 84.6mm / 3.33"
    Barrel (case base to muzzle 87.7mm / 3.45"
    Chamber depth: 16.18mm / 0.637" +/- 0.0254mm / 0.001"
    Sight radius 116.75mm / 4.6"
    Sight height (above bore center): 17.78mm / 0.7"

First impressions:

 

The large green box lid cam off to reveal a manual, a lock, 2 magazines and the gun, buried in 2.5" of foam. The two stainless steel magazines have plastic floor plates and followers, and really stiff springs. They hold 7 rounds each and the last round is really hard to get in (more on that later).




The gun is black, matte black. The slide is stainless steel finished in black nitride. The frame is black anodized aluminum. Feels really good in the hand and points naturally. With grip panels with a little palm swell, (or a double stack frame)it would fit my hand as well if not better than my Browning HiPower and for me, that is saying a lot.

Sights are tight. At least, they do not move under finger pressure. Very visible and easy to pick up.

Slide is tight and a bit rough. Yes, it is hard to rack. Is a lot easier if the grip safety is fully depressed and even easier if the trigger is held back while racking. Then release the trigger so it will reset. Slde doesn't hang or remain open or even seem to want to. Return to battery is strong. After stripping, cleaning and regreasing, including the rails which did not appear to be greased initially, slide is smoother.

Trigger has some side to side play but it doesn't seem to have any detrimental effect. Pull is crisp with about 1/8" take up and a clean break around 5-5.5#. Escept fo the side wobble, it feels almost exactly like my BHP (w/o mag safety). I don't know why the side wobble is there. It feels like the pin hole is oversize for the pin. Maybe a bushing would help.

Grip safey is not stiff. Disengages with noticable pressure. There is an audible click but it is not loud. It offers enough resistance to prevent inadvertent depression but not enough to interfere with functioning. Anyone using a grip with push-pull tension should have no problem with the safety. Using a thumbs forward grip with side to side tension may result in erratic depression of the grip safety. It may take concious effort to remember to depress it.

The overall feel is a bit rough, but is about what I would expect from newly machined parts with a matte finish on the bearing surfaces. Should smooth out with use.

Field Strip

To field strip, you have to pull the slide back to align a take-down notch with the slide stop pin and hold the slide, which is under tension from the recoil spring, in this position while you remove the slide stop pin. The end of the slide stop pin is recessed in the frame and tool of some kind is required to get the pin slide stop out—I used the corner of the mag floor plate.

Once the pin is out, you grasp the barrel by the fine knurled ridges machined into it and pull the barrel and slide assembly forward and off of the frame. While still holding he barrel, you can remove the breech block. Once the breech block is out, release the barrel.

The recoil bushing is a round sleeve in tront of the chamber Push the recoil bushing forward until it aligns with the notches on either side of the slide, Then tile the barrel and bushing upward and remove the barrel. Remove the bushing ans spring and field strip is complete.

A Look inside

The breech block does not have any rough spots on any bearing surface. In fact, the camming surfaces appear to have been polished.

Some reviewers have reported gouges in the frame where it blocks the breech block, but there are none present on mine either out of the box or after hundreds of hand cycles, but I haven't been to the range yet. The "gouge" points are the surfaces that block the breech block. The finish is worn off at these points from hand cycling the action, but there does not appear to be any deformation of the metal.
Forward Frame Rails

Locking Block & Disconnector

Locking Block Detail


There are no machined grooves in the barrel channel of the slide as recorded in some videos. The bore is bright and the rifling is sharp. The chamber looks dull in comparison (more on this later). There are what look like spiral boring marks inside the spring shroud of the slide but they are smooth to the touch.

The barrel is fixed in place. It slides into grooves on the inside of the frame rails and is held in place by the slide stop. The recoil spring fits into a bushing that slides over the barrel and is stopped by the chamber shoulder so the barrel serves as a recoil spring guide. This design places the bore axis 25% lower than in others guns of the same class.

Remington says that any disassembly/stripping beyond field stripping should be don by factory techs. Looking into the frame it is easy to see why.

For one thing, the internals are fairly inaccessible, and the sear pin, trigger pivot pin, hammer pin and upper safety pin (my names) all hold multiple parts in place, which includes springs that are saddled around other parts. Slave pins will absolutely be required for the sear and trigger and probably the hammer and safety which can't be easily seen with the grip safety in place. I wish I could find a schematic.

The trigger assembly is attached to a stirrup (like a 1911 or the 51) which may be further attached to the sear or safety assemblies (it extends into an obscured space and can't bee seen) I would like to try to put a bushing in the trigger pivot hole to take out as much of the wobble as possible, but I'm not sure I can get the trigger assembly out. I am sure I would need a slave pin (or a frame width bushing acting as a slave pin) to put it back in, and if I can't get it out, I can't install the slave pin to get it back in. Fortunately, the wobble is the only thing about the trigger that is objectionable enough to require attention.

Magazines

The magazines are stainless steel.The floor plate is two piece plastic. A hole in the external plate allows you to depress the plate inside and remove the external plate by sliding it forward. This allows the internal base plate, spring and follower to be removed (and if you don't hold it in place, the plate will remove itself and fly across the room). The follower is plastic as well.

The stainless sheet metal is welded at the back and the seam ground flat. There have been reports of this seam splitting where it was ground to thin, so need to look fro that. The index hole in the side line up nicely with the rounds inside making capacity easy to check. There is a cut on each side for the magazine release.

There are is a groove pressed into each side running top to bottom which keeps the bullet nose centered in the mag. A lip at the top front forces each round to the back of the magazine as it feeds. There are reports that is lip can cause really wide hollow points to hang up and fail to feed. All this is necessary because the mag well is over sized and the magazines fill it. There is plenty of room in the mag well to accommodate .40 S&W, is an obvious possibility, but .45ACP could be possible with the right bullets. I doubt bottleneck cartridges such as .357 Sig would like the delayed locking of the breech. It would almost certainly blow out the shoulder and severely reduce case life for reloaders.

As noted, the spring is really stiff and the last round loads with difficulty. I'm concerned that the spring may be pushed beyond its tolerance range which will weaken the spring if left in this condition. This will bear watching for problems feeding the last round or locking back the slide. It may turn out that the last round needs to be chambered immediately to save the spring, making the working capacity 6+1. Until more mags are available, I'm only going to keep 6 in the two I have.

Grips

The grips are flat checkered plastic panels set into the lower 2/3s of the grip frame. They are held by 2 screws each. The screws are hexhead screws and at least one looks like a TORX head with the teeth worn down. Others have reported needing TORX drivers to tighten the screws but a hex wrench worked fine for me. The screws may work loose, so a little loc-tite may be in order. This is important because the grip panels capture a pin that holds the top of the grip safety in place. This is the only loose pin on the gun and can easily fall out when either grip panel is removed.

After market grips should be easy to make, but thicker grips requiring longer screws will be a problem. The screws have a ultra fine thread pitch yet to be identified by anyone or disclosed by Remington. I'm guessing they determined fine threads work better in the aluminum frame.


Next pust: A look at the Pedersen action.