I remember back 10 years ago or so, there were a lot of complaints on the various forums about BC gaps (S&W and Ruger) being too big. .010 were being reported, and folks were upset about it.

Over the past few years, all the revolvers I've purchased have BC gaps that are neigh on too tight. For example: My new model 69 has a BC gap right at .004 That's quite tight, and right on the edge of being too tight for extended shooting.

My Ruger SP101 (new) has a BC gap of .003. That's tight. My new GP100 has a BC gap of .002!!! It hasn't stopped revolving, but I'm a little concerned about that for long term shooting.

I know that the trend of shooting semi-jacketed and jacketed bullets make the small BC gap less of a concern, but it would seem that gaps of .003 and .002 are starting to get way too small for useful field guns.


Has anyone noticed this trend in ever-shrinking BC gaps on new revolvers?

Can't say that I have, but I haven't bought an actual new revolver in over a year. My own opinion, for what that is worth, mirrors yours. Anything less than 0.004 may start giving reliability problems and really offers nothing to gain.

My brand new (2 w.o.) 686+ Deluxe has a b/c gap of .003". I fired approximately 50 mag rounds through it, mixed 125gr WM JHPs, Blazer 158gr mag medium loads and a friend's 125gr mag handloads ("What is a handload?" ) My cool Forum buddy 75Vette had suggested I bring a bore brush to the range just in case, but it proved unnecessary. Am still up in the air about trying lead mag rounds, but not knowing is driving me up the wall.

FWIW, I had no intention of buying a gun that day, but the timing was spot-on, and there was none of the cylinder looseness I had seen on 2 previous 7-shot .357 Smiths. This 686+ is not as refined as my recent 627s, one Pro and one PC, but it will definitely NOT go out with the recyclables this weekend.

Kaaskop49
Shield #5103

I haven't measured it yet, but I believe my GP100's gap is too big, as it sprays residue every time I shoot it and I can actually see the gap very easily and I'm sure it's too big. How do you know what it's supposed to be? I suppose call Ruger? I bought it new in December, but haven't had it out more than twice. I would think I should measure it since it does spray residue back at me and call Ruger?

Feeler gauge will do the trick.

Spitting can be from timing that is slightly off. Or the gap can be too big.

Call Ruger. Their customer service is the best out there.

I think the spitting is more likely a timing issue! Time for a trip to the mother ship. Hve Ruger send you a shipping label, even if they charge you for it! Their rates are so much better!

Ivan

I'm glad you're enjoying your new one. I would think jacketed or plated rounds would be good all day long. I could see lead bullets building up crud on the forcing cone and making it hard for the cylinder to turn. A brass brush across the cylinder face and forcing cone would clean it up. I've started using Hi-tek (powder coated) LSWC bullets for my reloads with great results. I do miss all the smoke though.

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Don't You Ever Wash That Thing

Heck, I would pay extra for revolver guaranteed to have a tight .002"-.004" cylinder gap. I have a Freedom Arms .454 with a .002" B/C gap, and an older DA Colt with a .005" B/C gap. I think every thing else I have has B/C gaps in the .006"-.012" range. With a S&W 642-1, purchased new a few years ago, at the top of that B/C gap range. Many of the S&Ws I've purchased over the last 25 years or so were .006" or greater. A S&W 610 was .011". Easier for manufacturers to build guns with loose B/C gaps which masks imprecise machining, end shake, etc. issues. Kind of like newly manufactured 1911 type pistols with lots of "Battle rattle" in the barrel/slide/frame fit......

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NRA Life, COTEP 640

What is the maximum BC gap without having issues? I have noticed that recent S&W's are very tiny BC gaps.

Depends.

If I am shooting a low pressure cartridge, like 38 Special wadcutter ammo, then a 0.003" gap is just fine. But that same 0.003" gap when shooting 357 magnum loads with lead bullets might accumulate lead fouling and quickly bind the cylinder. For most calibers, I think a 0.006" gap is ideal. Gaps larger than 0.006" tend to allow more combustion gas to vent between the cylinder face and forcing cone and that is bad for achieving maximum velocity. Gaps of less than 0.006" can cause binding issues with the forcing cone.

Just my opinion, consider it to be worth what you paid for it.

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VCDL, GOA, NRA

Sounds like another good excuse not to shoot lead.

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Release the Kraken

Not sure where you guys are finding new Smiths with tight gaps . I carry a feeler gage when I go to gun shows and the LGS . Most new Smiths average .008 but a PC 629 I checked about 8 months ago had a gap of .014 !

As I understand it, S&W's current specs consider a gap of 0.014" to be the maximum limit. I think that is twice the necessary gap, but S&W considers it good.

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VCDL, GOA, NRA

I have two "identical" revolvers (Model 66s), except one has .012" gap vs about .006 " on the other. It gives old timers like me an odd feeling to look at a .012" gap, but the truth is they shoot equally accurately, with the wider gap chrono about 30fps slower with my slightly +P competition ammo.
Usually the noticeable issues are due to something besides simply having a gap on the high side, e.g., uneven gap, timing, end shake, worn cylinder notches, etc.

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Science plus Art