I can't believe this...more gap problems from S/W

[Blueduck]

Some may recall I had some problems with S/W and an uneven cylinder gap among other things on my model 19. I had also sent in a very old model 65 at the same time as the 19's second trip (about 8 weeks ago) for an excessive gap. Charged $64 for resetting the gap, just got the gun back today.

Velocities should be great guys! It'll barely take the .0015 feeler and won't even think about the .002" one! I honestly am not even a bit upset. At this point it would be like blaming a one legged man for loosing a butt kicking contest.

Question though.. Could I carefully use a stone or very fine file on the forcing cone to give myself a little breathing room??? If this is possible might also be interesting to chrono some loads through the process...

 

[CMcDermott]

I'd leave it alone until after I did some testing. If you can fire 4-5 cylinders full to heat the gun up good and dirty it up some, then fire another cylinder full without any binding issues just leave it alone.
If it binds up - and you are good with a stone and can keep the back of the barrel flat and square - then you might want to open the gap up another .001". I'm betting that with full power loads the gap is kept clean by the high-pressure blowby and you won't have any binding issues at all. Sounds like you have the tight gap of a Freedom Arms revolver and it really doesn't get any better.

 

[Jim March]

What he said. In spades.

It will probably shoot OK at .0015". If not, any small knife sharpening stone that's in good shape (read: dead flat) that can fit in the frame window can gently polish the back of the barrel. Go dead slow, you'll get *exactly* what you want.

I would view a gap like that as more of an opportunity versus a problem, and would not turn down a new gun in that condition. Granted, it's annoying on a gun that just came back but...you're not hosed here.

 

[Old Fuff]

Another question: Is they're any end shake (back-and-forth movement of the cylinder)? If so, and it was corrected you might come out with a "perfect" gap. Or if after some shooting the cylinder developed some end shake the same answer would apply. That tight gap may work unless you shoot soft lead bullets. At the moment I don't think you have a problem, and until you do I wouldn't fix it.

As an aside, the other day I was checking out an older Model 10 - made around 1986. It had a gap between .007 to .009, which many would consider to be way excessive. But I think S&W revolvers of yesteryear had on average, wider gaps because soft, swaged lead bullets were what was normally used at the time. I will be interested to see if shooting/accuracy tests show any problems with this wide gap.

 

[Jim March]

I'm able to shoot 38+P LSWC-HP 158s in a 38snub with a .002" gap. The back of the barrel and cylinder face need a wipedown after roughly 30 - 40 shots.

I have no problem with that, when the payout is velocity. Snubbies need all they can get.

 

[bountyhunter]

Question though.. Could I carefully use a stone or very fine file on the forcing cone to give myself a little breathing room??? If this is possible might also be interesting to chrono some loads through the process...

Yes, but before you do: meaure the cylinder end shake and make sure it is in spec (less than .002"). If you have wear on the crane tube end (and the end shake that results from it) it causes the cylinder to move forward and tighten the b/c gap. Don't shave the forcing cone until you make sure the cylinder is where it's supposed to be. If you have too much end shake, it can be tightened with either washers or peening the end of the crane tube.

 

[bountyhunter]

The only bad thing about such a small gap is that it might bind when the gun starts to get dirty.

That, and you can bend the crane when trying to swing the cylinder back in if there is dirt or lead build up on the cylinder face. Gap should be .003" at least.

 

[Blueduck]

Thanks for the replies folks, least it doesn't sound too bad an issue to deal with. I'll try it out with my reloads this weekend and see what it does with this gap, it's all pretty academic though, gaps gotta be larger eventually...

You haven't even shot it yet and you're asking if you should start grinding on it? How about testing it first?- SaxonPig

Because where I work they inspect individual carry guns, among other things gap of less than .003" or more than .010" means the gun fails and you can't have it on record as a carry gun till it's repaired.

 

[J Miller]

Blueduck,

If it were for my personal use I wouldn't give it a second thought. I'd leave it as it. But since you have to obey the rules on indivual cary guns this is what I suggest.

Let them check it. If it fails, then go to Brownell's and buy one of their tools that is specificly for squaring of the end of the barrel and adjusting barrel / cylinder gap.
I suggest this because it will give a perfectly square cut , a lot easier than stoning it.
The other thing you might need to look at, is if you cut .0015 off the end of the barrel, what is that going to do to the forcing cone?
Maybe nothing, maybe a lot. Depends on how S&W cut it when they adjusted the b.c. gap.

 

[Blueduck]

I'd actually thought about the forcing cone, assuming a few thousandth's shorter would not affect anything.

Anyone think it would???

 

[Frenchy]

Because where I work they inspect individual carry guns, among other things gap of less than .003" or more than .010" means the gun fails and you can't have it on record as a carry gun till it's repaired.

Is that your district policy BD, or state? I ask a couple of fellows (OK..One gal) about it, and they weren't familiar with this.

 

[Blueduck]

Trainers do the check at qualifications and practice shoots (or should be) where they check head space, cylinder gap, timing, trigger pull weight (must be over 8#'s)., hammer drop weight (never saw that before or even heard of it) and examine for signs of spitting. If it has signs they check it out with range rod.

Nice one adjusted my yoke one time and let me go on my merry way. I've seen them let guns go that are too tight go on and just tell them to clean betwen 60 shot courses. Never know when your gonna run into a stikler though. Trainers are assigned to regions and maybe yours are doing it different, and maybe some are just more lax than others. But from speaking to mine I was told the .003"-.010" was the accepateble range, thats also Smith's official range of acceptable gap which is where I assume they got it. Can't imagine they would be develping standards outside the companies on a district or regional level, but hey it's DOC I've sen odder

Did get a chance to shoot it today, just had 100 rounds of my handloads which are WAY cleaner than the practice ammo we get. At about 20 rounds I was having some "sticky" pulls as expected. Tied up pretty good once it got hot and went on to other guns.

Least it Doesn't sound like a hard fix.