Enfield revolver no2 mk1 cylinder gap specs revisited

Here's a question for the gun plumbers. Picked up a pretty nice looking No.2 Mk1* that appears to have been on a shelf since its last FTR in 1954. Alas, loading it up, there is insufficient clearance; the cylinder virtually locks up trying to fire. In researching around the forum I came across this tidbit.

Rear 0.07" must pass across striker hole
Front, with cylinder held forwards. Must be between .002" and .018" on each chamber

FPP, ,040" and .050"

This particular revolver at the rear will pass a snug .049 across the firing pin hole. The gap with the cylinder forward is between .018 and .022. After removing the cylinder, there is a shim on the cylinder spindle that were it about .010 thinner would close up the cylinder gap and increase the headspace to where the cartridges won't drag.

The shim, or whatever it is properly called, does not appear in any parts diagram I have found. What I would like to know is did the REME have an assortment of these shims to pick from to get the clearances correct? If so, where to find such an assortment now.

I suppose that I could just lap the shim presently installed until enough clearance was achieved to allow the loaded cylinder to turn acceptably, but will cylinder moving forward affect the timing enough to worry about? As long as the cylinder stop is firmly engaged at the time of firing seems to me should be safe enough.

Looking for advice on the best way to proceed. I have loaded a bunch of 200 grain lead bullets to duplicate .380/200 Revolver Mk I and I want to shoot it.

Those shims are available to you through sources like Brownells and people with little or no pistolsmithing knowledge or experience install them to "Tighten" something that isn't at fault to begin with. I'd suggest removing the offending shim and put the feeler gauges away, take it out and let fly. I think you'll find it will load, cycle, discharge and put a bullet downrange just fine. They aren't a Jerry Miculek special or even approaching it. They were to defend one's self. Put things back to original and enjoy.

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Originally Posted by browningautorifle

Those shims are available to you through sources like Brownells and people with little or no pistolsmithing knowledge or experience install them to "Tighten" something that isn't at fault to begin with. I'd suggest removing the offending shim and put the feeler gauges away, take it out and let fly. I think you'll find it will load, cycle, discharge and put a bullet downrange just fine. They aren't a Jerry Miculek special or even approaching it. They were to defend one's self. Put things back to original and enjoy.

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I considered that, but with the shim removed, there is no clearance at the front of the cylinder, while the CHS is .078. So then it is a mystery, if the shim was not installed during the 1954 FTR, where did it come from? If it had an CAI import mark, that would explain things. How did armorers adjust the fore and aft position of the cylinder to assure the proper clearance on both ends?

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Originally Posted by old tanker

if the shim was not installed during the 1954 FTR, where did it come from?

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From John Q Public a short time ago, pistolsmithed by a previous owner. Have you tried it without shims? Not tried to analyse it, just shoot it? They're usually loose anyway.

Peter will eventually be here and explain how he used to sort these I'm sure. If not we can always ask him outright.

The more I look at this old revolver, the more I wonder about it. The finish looks like typical military phosphate, and there are no import marks. It appears not to have been fired since the refinish, which if it coincides with the FTR, was 60 years ago. Perhaps I was deceived by the appearance. But with no turn line on the cylinder, no loss of finish on the recoil plate, nice lock up, I did not expect that the cylinder would bind when I tried to fire it. Measuring the rim thickness of the brass, the Winchester nickel cases measured .056 while the Starline brass miked at .058, it was pretty obvious why cylinder did not want to turn and the trigger pull increased to where you wondered if that's what the 3-1/2 tons stamped on the frame meant. So when fitting and repairing these revolvers, how did the Brits ensure the cylinder was properly positioned to have the correct clearances? Was it all supposed to be controlled by the Cylinder Retaining Cam? Likely whoever stuck that shim in there did not use proving dummies or try to fire it.

The first question is this. Have you tried cocking it and firing it from the cocked position? The shield should be phosphated or polished and NOT painted, So you could try polishing it. The SCREW, shield MUST be below the face level of the shield of course.

I'm not going to go through the complete EMER to find the technical spec you mention because they are all recorded here somewhere, taken straight from the UK Military bible. I suspect that the spec figures you have quoted from elsewhere probably came from this site originally!

As for the notion that you have a shim of sorts at the front of the cylinder is alien to me. We never used shims to adjust the cylinder end float. Maybe you could put up a picture of the 'shim' and maybe I can identify it.

One other test we had was to fire off the pistol in all 6 stations by dropping the hammer under control of course, hold in the fired position and try to rotate the cylinder in each station. It should be held solid between the cylinder stop (that is under the cylinder) and the pawl (that protrudes through the shield).

It would appear you have one of 3 things. 1, a revolver that was FTR'd 60+ years ago and has again been refinished quite recently. 2, a revolver that has had a shim added to bring it in to some unknown spec or 3. A good gun untouched since it was FTR'd and the figures you are using are incorrect.

In my opinion it is most probably option 1, a recently refinished gun. Even a stored FTR'd gun would be subject to some kind of maintenance and would exhibit signs of having the action tested and probably dry fired. Peter can confirm if that's correct. Can you post photos of the gun?

If the finish is phosphate with no baked Suncorite paint finish present and doesn't have wear from the cylinder stop, I'd guess it's been refinished post UK service. It's possible someone added the washer after the refinish since they are readily available from places like Brownells. I'm guessing of course but the fact that it doesn't have baked paint on top of the phosphate is a red flag for me.

I've done lots of matt bluing and parkerizing too, so a fresh looking revolver is no measure of it being new from refurb 70+ years ago. It's been dicked with...follow Peter's instructions for testing lockup.

No doubt Bubba has done some mischief. It is clearly apparent the shim does not belong. The attached pictures give a quick look at what there is. No suncorite paint so the refinish is not from the FTR. The wear on the recoil shield is from the cartridges rubbing with insufficient clearance. Not the circles by each chamber you normally get when a revolver is carried loaded.

You can see where the shim was on the axis pin. It was not initially apparent as it was firm against the frame. With it removed, the cylinder just kisses the barrel on a couple of the chambers. The bright spot is with the trigger pulled and held, the cylinder stop and pawl hold the cylinder firmly in position on each hole. Additionally, now there is .017 clearance between the case head and the recoil shield.

Doubtless, as Brit Plumber has surmised, it has been dicked with, refinished at some point after the FTR, and God knows why, a shim added by somebody.

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Originally Posted by old tanker

as Brit Plumber has surmised

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Really...just him? Check post #2.

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Originally Posted by old tanker

God knows why, a shim added by somebody.

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Go back and re-read from the start and you'll see why it was added. Those are the ones you can buy in sets from Brownells and others...for tightening a loose Mod 10 S&W for instance...

It looks like someone has refinished the main parts but left things like screw heads in black sunc. The firing pin has been replaced as the locking rivet/pin isn't original and has been filed flush. The cylinder may have the original finish, it's hard to be sure but I do see over spray on the face of the recoil shield so it has had some paint applied at some time. Does the cylinder, frame and barrel have matching serial numbers or are there marks where one or the other may have been removed?

But, back to the problem.......... Get rid of the shim. It should not be there. End float of the cylinder is controlled by the cylinder stop cam acting in the groove in the extractor guide*. You test the cylinder/barrel face gap by feeler gauges holding the cylinder forwards.
* the extractor guide is the central axis of the cylinder that the extractor slides in. They do move slightly but I won't complicate things more.......

Pictures are worth a thousand words. The description in post 5 leaves me a bit befuddled. It looks pretty honest to me and has certainly been fired since refinishing. Remove the washer and drive on forward.

---------- Post added at 08:22 AM ---------- Previous post was at 08:20 AM ----------

By the way: when I work on firearms, does that mean they're "dicked with"? :madsmile:

The barrel, frame and cylinder are all stamped with the number Q2179. The problem with the revolver did not manifest itself until I went out to shoot it. The heads of the cartridges were so tight against the recoil shield the cylinder would not advance when you tried to pull the trigger. I started troubleshooting by measuring the space between the shield and the back of the cylinder with the cylinder held forward and the thickness of the rim of the cartridge. With the brass measuring .056 and the space measuring .049 the reason the drag was plain, the question was why, what should be and how is it supposed to get there started the search.

When the shim was discovered, the questions multiplied!! Is this supposed to be here? Is this how the fore and aft float is controlled? This one seems too thick, do they come in sizes? That quest lead here.

With the shim out, the cylinder will just rub enough to remove a chalk mark on the edge of 2 chambers, so that clearance is minimal. The clearance at the back of the cylinder is generous, it will pass a .070 gauge. I suppose if the firing pin is long enough it should go bang. That was suggested upthread, and shall be the next step.

The gap between cylinder and shield should be 0.060" - 0.066".

I have put together 1930 Enfield with renumbered barrel and cylinder with s 0.082" gap which I've had to retire.

What you are describing in thread 15 is wear in the cylinder stop cam and/or the wear in the corresponding groove in the extractor guide. If it were my revolver and I didn't have access to those parts I'd just remove the shim, take it to the range and shoot it. It ain't going to let you down. You ought to invest in a little book by Mark Stamps. It's not a technical book as such but very good all the same.

Incidentally, the technical spec for the UK Military simply states that the .070" gauge must not pass between the recoil plate and the rear of the cylinder when the pistol is in the rebound position. While not arguing the point with Baal (thread 16) it doesn't specify a minimum spec. Just the one GAUGE, Slip .070"

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Originally Posted by Peter Laidler

...I'd just remove the shim, take it to the range and shoot it. ...

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Took your (and BrowningAutoRifle's) advice, removed the shim, reassembled the revolver and test fired it after work today. Three cylinders full, no malfunctions. The results at 25 yards show that it is quite good enough for government work.

Cursed mightily whoever installed the shim, all his ancestors and all their progeny. They went to a lot of trouble making the damn thing as the dimensions do not duplicate anything Brownell's stocks. It had me confused for certain.

Once everyone here made it clear that the shim was bogus, I could see exactly, as you said, how the stop cam and the groove in the cylinder control the cylinder's position. If I stumble on to a new cylinder stop cam, I might try it to see. I shall look for Stamp's book, as you recommend.

Thanks to all here for all the advice and in helping me understand how this revolver was supposed to have been put together.

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Originally Posted by Peter Laidler

While not arguing the point with Baal (thread 16) it doesn't specify a minimum spec. Just the one GAUGE, Slip .070"

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Those numbers are from Stamp's book.

You're dead right Baal! I suspect that they have been superseded now by the EMER's from 1947 to '70 for one gauge.