Cylinder fitting question

[tek4260]

I received another cylinder for my well worn OM Super today and fitted it to my revolver. The original cylinder measured 1.950" and had about .006 endplay. I installed a .005 gas ring shim but this set the b/c gap at around .009.

The new cylinder was 1.958 by my caliper, so I carefully stoned it back to 1.956 on a ceramic stone keeping it perfectly flat. It is a bear to install but once in, turns freely. I have 0 endplay, or at least not enough to feel or measure even when using a small screwdriver to pry a bit. The b/c gap is .005 which is wider than I'd like, but I can live with it. I also have a Belt Mountain pin installed that I had to polish down to install it thru the cylinder. I checked timing and barrel/cylinder alignment with my 44 range rod and everything is good.

Is there any problem with setting one up this tight?

[44man]

Yes, you might get binding and galling when the gun gets hot. Metal expands with heat.
I have never found the cylinder gap to be very important and a few thousandths will not hurt anything but the end play should move a small amount. You don't need much unless you shoot 40 to 80 round IHMSA matches in the hot sun.
All cylinders need some play and even too tight of a pin can ruin accuracy. Allow the boolit to align the cylinder.
I use STP on the pin and ratchet, that gets it on the front bushing too. Do not shoot the gun dry.
Tight guns must be PERFECT and even Freedom can't do that with every gun or every chamber.
My SBH has well over 61,000 rounds through it and I can not measure any wear. It still shoots like it did when new. LUBE! Cock the gun slow and it will last forever, shoot cowboy stuff and you need a lot of money to keep a gun in shape.
Even a bolt action needs some lube on the lugs or head space will increase from wear.

[tek4260]

I keep mine clean and well lubed. I rarely shoot more than 50 rounds in a day and probably no more than 10 or 12 in a row without at least a 10 min break for that revolver. Never have been one to cock a gun fast either. More worried about breathing, sight picture, and grip than speed.

[S.R.Custom]

... Is there any problem with setting one up this tight?

Shoot it and see. Chances are you didn't get everything as flat as you thought you did --and certainly not in relation to the already "flat" surfaces of the receiver itself-- so after 50-100 rounds or so, you'll notice the endshake surfaces break in a bit and open up. But if things bind up before then, you'll need to take off another .001". And at this point, if that's necessary, I'd do it with a polishing compound instead of more stone. Apply the compound to the bearing surfaces, assemble the cylinder in the gun, and work the parts together by hand. That way just the surfaces that are actually touching are taken down. There are no advantages to endshake; the tighter you can keep it, the better.

[missionary5155]

Greetings
Barrel Gap...
Dan wessom revolvers addressed this situation (well as a side line) with the interchangable barrel system. I bought my first back in 1978 in Chattanooga Tn and have been adding ever since.
I have experimented with barrel gap with the 357 mag, 375 Supermag, 41 mag and the 41 Supermag. All shoot beter with as little Bartrel gap as possible. But they each must have near perfect lockup. Dan wesson instructions said to use the .006 supplied gauge. Steel shooters figured out real fast that was too much. Most DW shooters I know found .003 was plenty wide and somewhere between .0025 and .001 gives the best accuracy and least "Spitting". This does mean keeping the cylinder face clean and in some cases the cylinder face needed a bit of attention to flaten out a high side.
I have other brand revolvers with much wider gaps. They shoot well.. but sure do leave a "ring" on my leg mounted blast sheild when I am shooter creedmore style.

[44man]

Shoot it and see. Chances are you didn't get everything as flat as you thought you did --and certainly not in relation to the already "flat" surfaces of the receiver itself-- so after 50-100 rounds or so, you'll notice the endshake surfaces break in a bit and open up. But if things bind up before then, you'll need to take off another .001". And at this point, if that's necessary, I'd do it with a polishing compound instead of more stone. Apply the compound to the bearing surfaces, assemble the cylinder in the gun, and work the parts together by hand. That way just the surfaces that are actually touching are taken down. There are no advantages to endshake; the tighter you can keep it, the better.
That is the best way. You just don't want .0000 clearance. Thickness of oil film on both sides would be about right. That is how I fit new S&W bushings, lap them gently once the cylinder goes in the frame.
Had fun with a Dan Wesson with wobbly cylinder fronts. Set at the wrong chamber and the gap would lock up the gun with the next chamber. I had to send it in to be fixed, I didn't have a lathe.

[tek4260]

That is the best way. You just don't want .0000 clearance. Thickness of oil film on both sides would be about right. That is how I fit new S&W bushings, lap them gently once the cylinder goes in the frame.
Had fun with a Dan Wesson with wobbly cylinder fronts. Set at the wrong chamber and the gap would lock up the gun with the next chamber. I had to send it in to be fixed, I didn't have a lathe.

That's why they recommended .006. It let them be a bit sloppy on machining.

[S.R.Custom]

I had one of the early (well made) Dan Wesson .445 SuperMags, NIB, back in the 90s. The manual, a generic edition, specified .006". But the feeler gage supplied in the box was .002". I've not seen an SM so equipped since then.

I'm currently working on a Ruger Maximum/.445 conversion that features .0005" end shake, and .001" barrel gap. Shooting its accuracy load over a chrono, the ES across all 6 holes is 7 fps (of 1500 fps), and the SD is 3. There is something to be said for keeping the leaks to a minimum.

[tek4260]

Got around to shooting it today. Did fine with no binding or other issues as far as I can tell. Maybe I can get around to shooting some more tomorrow. I have about 300 rounds loaded with 240's that I would like to load with 300's over H110 without getting into my stash of brass.

[S.R.Custom]

Sounds like you're golden... ;)

[44man]

My Dan Wesson also came with a .002" feeler and instructions said that was the gap. I think .015" would have been about right for the wobble.
On top of that the barrel was not in the frame straight and I found a part inside the action that did nothing that needed fixed. The gun went bye, bye! :groner: