As posted elsewhere, but figured you guys would have the best info:

I was trying to sell my S&W Model 19-3 (reluctantly, mind you). I thought I had a local buyer. We met, he inspected the piece. After overlooking it, he brought out the feeler gauge. Up until now, I had not thought much of barrel cylinder gap. I figured if it shoots well, it's fine. If it spits lead in my face, well.... He checked the gap and found it to be nearly .010, to which he said .08 was the max accepted tolerance and that this was an abomination. He had a look of horror on his face, and nearly ran off screaming. To me, I didn't make much of it, said no problem, thanks for your time and guess I'll just have to go research the topic. Upon looking up S&W tolerances, apparently .002-.012 is within spec. Granted, S&W has laxed a bit on tolerances over the years, but even they don't see anything wrong with this. I'm fine if he wanted a perfect example, and don't even regret the sale not going through because now I'm even more intent on throwing it back into the stable and shooting the S*** out of it. If nothing else, I walked away more educated on the subject and for that I'm grateful as I then did some research. Minus losing a few fps out of my loads, the larger gap doesn't seem to be a real issue from what I've read. He also said it was shot a bit more than the previous owner or I had thought by pulling out the loupe. I expected a gun nearing its 45th birthday to have been shot by someone down the road...so that I could care less about.

Question comes down to, while .010 is nearing maximum acceptable tolerance levels, if it shoots fine and doesn't spit lead is there really a problem? I understand some guys standards are more stringent than others when it comes to these things, and like I said I'm fine with that. I guess if this is such a horrible example of a S&W I'll just have to go back to shooting it myself. Unless you guys think there's truly a reason for alarming concern???

I don't usually check the BC gap unless I think something is wrong. And even then I'm looking for consistency. If chamber number 1 is .004 and number 3 is .012, then we might have a problem. I might be concerned if you were talking something huge. But .010 wouldn'tbother me.

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I had a 3 in, 7 shot M686-6 that was made in 2011.
From one side the gap was .004 and the other it was .007 inch. On the same chamber.
I think I could beat that with a hack saw and a file!
It didn't affect the accuracy as far as I could tell.
The other end of the barrel is much more critical.


Best,
Rick

S&W has loosened specs over the years, with gaps of 0.012" being "in spec" according to them.

The test is: Is the gun accurate, does it spit lead?
If it's accurate and not spitting bullet metal, it's good.

It may cause older S&W owners to turn up their noses, but that's where S&W is today.
Given that, I would question an older S&W being that big, but guns made during some of the S&W ownership periods had quality problems.

I have a spread sheet where I keep track of revolver measurements, mainly the cylinder throats so I can tailor cast bullets to the throat diameters but also the B/C gaps as long as I was measuring things. My Bangor Punta era S&W's have B/C gaps that vary between .003" and .006". Looking at the chart, the only guns I own from any maker or time period bigger than .008" are an S&W Model 1917 made in 1918 and a Colt Peacemaker .22 made in 1975, both of which measure .010". I can see it on a wartime revolver like the M1917 but was disappointed that Colt had not held the tolerances closer on that particular gun. Other Colt .22's I have are within the .004-.006" range. So, I think it's more a matter of an individual gun getting out once in a while with specs at the upper end of the tolerance range with older guns, but I sure think the current "acceptable" range of .012 from S&W is a poor tolerance. Especially if the model is expected to shoot mostly jacketed slugs where the tolerances don't need to be as loose as with cast bullets that may build up some fouling on the cylinder face and breech face.

It appears that S&W has decided that wider gaps are not an issue, and the average owner seldom even notices the gap other then in passing interest.

Since to the average owner it's not an issue and he has no idea there even is a standard for the size of gap, it's easier and cheaper to build the guns for S&W.
On older revolvers of all makes, wide or narrow gaps were an anomaly, but now it seems wider gaps are standard.

And to be fair, a wider gap has no real effect on accuracy and minimal velocity loss that few people will even notice in any case.
When you think about it, purists may not like it, but what real real world effect does a few feet per second in velocity really cause.