Air gap between barrel and frame-Smith and Wesson 686?

[willie]

One factor affecting revolver accuracy is chamber alignment with barrel. Range rods are used to check this. The rod is inserted into the barrel, and if it slides down into each chamber, then alignment is considered good. Two types exist. One for service revolvers and another for target guns. Correcting misalignment can be a complicated procedure. Bullseye shooters would carefully test fire to determine if one chamber produced a flyer. If so, then it was not used.

After examining a large number of newer Smiths, I have seen many J frames that were good specimens. For some reason, I have seen fewer larger frame Smiths that were set up correctly. Sample size does not permit my making a valid generalization but has given me personal bias. I have studied S&W revolver gun smithing for 50 years and did learn from many factory trained armorers. These days, when I have called the factory, I have been dismayed at the ignorance of the employees I talked with. I would buy a Ruger revolver and not one of the larger Smith guns.

[TiroFijo]

My 686-4 from the early 90's has zero gap there, about 0.006" gap at the forcing cone after many thousands of rounds, and is extremely accurate.

[Wingate's Hairbrush]

I disagree that the gap is normally 2-3 thousands. 6-7 is more like it. I have seen large numbers at .008.

Check something else. You might discover that the front of your cylinder in not square, or that the rear of the barrel is not cut or filed square, or both, and despite what I tell you, you will not believe me when I say the damn gun is within specs this way, and you really might get mad when I tell you your feeler gauges are all fucked up too. And it makes no difference anyway.

There's a misunderstanding afoot: OP is asking about a gap in the contact point between the barrel shoulder and the frame, not about barrel-cylinder gap. OP wondered if the process for setting barrel-cylinder gap at the factory might explain the barrel-frame gap he saw on a revolver he was inspecting, which is an understandable speculation but as you know isn't correct as barrel-cylinder gap is set in the method you described in post #6.

So the .002-.003" mentioned regards the normal amount of gap at the top and bottom points of the barrel shoulder against the frame -- not barrel-cylinder gap -- where again you are correct that in the old days the factory aimed for around .006", but you could find them narrower or wider; then as now, up to .010" is considered in spec.

One member on another forum reports S&W telling him that .020" was in spec for the barrel shoulder gap at the frame, which seems to me excessive if true.

[Wingate's Hairbrush]

#2 and #3 make sense given Rufus and Skeeter are working on the S&W assembly line rather than the qualified gunsmiths of old.

#1 not so much. The older S&Ws (without gaps) are way more accurate than the new ones.

I don't know much about the degree to which thermal expansion can or cannot affect accuracy in handgun; I can see it as a theoretical, particularly for stainless, depending on clearances and tolerance -- but I nonetheless do trust the source who posted it.

As for #2 and #3, I'd assume that's the reasoning, too, though I can make a case as well that the clearance top and bottom of the barrel might also make machining easier in the event that the barrel needs to be turned.

I read much about accuracy of older era S&W revolvers versus today and find informed arguments in both directions and consider the issue controversial and unsettled, and ultimately probably a lot more to do with the individual firearm example rather than the era in which it was built.

Yes, I prefer the older guns for a lot of reasons, and I really miss the era of knowledgeable parts fitters versus the age of assemblers we're in now. But I can't deny at least some merit to the arguments that today's design updates and advanced metallurgy and machining might in aggregate make for a better overall S&W revolver, and the claims by some that the two-piece barrel design -- with tensioning at both the muzzle and the shank -- yields a more inherently accurate gun.

But I don't know. I point them and pull the trigger and generally like the result, whichever era I'm shooting.

[Dave T]

I have two S&W Heavy Duties, one from 1938 and one from 1953. No gap to be seen. I have a 25-2 that late in life had a Model of 1950 tapered barrel installed by my gunsmith friend after he shortened it to 4", making a 45 ACP blue steel Mountain Gun, a version S&W never produced. No gap to be seen. And all this in contrast to the previously mentioned 586 that had a gap so noticeable you didn't need to hold it up to a bright light.

YMMV,
Dave

[Pistol Pete 10]

My guess is that this is a manufacturing shortcut to keep from having to fit it.

[FrankB]

I’m watching a Hickok45 video, showing his 1980 Model 629, with a pinned barrel. There is clearly a gap between the under lug and the frame.


The pics are all of the same pistol. While posting the pics, I seem to notice a gap in the upper portion of the barrel as well. Let me know what you see. The bottom pic shows the gap(s) best.

[Rmiked]

Agreed. Looks like gaps on both but not at barrel bearing area. Only underlug on rib portion above barrel.

[41magfan]

Having owned more than a few dozen post-war S&W revolvers in the last 47 years, it's been my experience that barrel fitment is a QC issue that has come and gone a number of times throughout the the company's ownership and management history.

I owned a Mod 29 Classic a few years ago that had a lower/shroud clearance of thirteen thousands and S&W said that was within specs. The gap was so unsightly I attempted to have the barrel set-back and my gunsmith couldn't get the barrel off. He's been dicking with S&W's (he was an Authorized S&W Warranty Service Center back in the day) for a long time and he said he had never encountered one that tight.



Most of the better put together guns I've owned had NO clearance on the upper portion of the barrel and a thousands or less on the lower/shroud portion of the barrel.

Fitting barrels properly takes some skill and a bit of time, neither of which is good for the bottom line. I'm fairly certain that fitment is done with a machine these days so a predictable amount of minimum clearance is required to prevent damaging the frame. The notion of "excess" clearance apparently doesn't exist in their minds.

[Pol]

I’m watching a Hickok45 video, showing his 1980 Model 629, with a pinned barrel. There is clearly a gap between the under lug and the frame.


The pics are all of the same pistol. While posting the pics, I seem to notice a gap in the upper portion of the barrel as well. Let me know what you see. The bottom pic shows the gap(s) best.

Agreed. It does look like a gap top and bottom.

I’m picking up a Model 24 tomorrow, so now I’m really worried. If it has a visible gap it’s going back to the seller. I don’t care what S&W says. A visible gap would bug the hell out of me.