What to do about barrel constriction at barrel/frame fit?

[john c]

I have several revolvers (both Ruger and S&W) that have a noticeable barrel constriction where the barrel screws into the frame. I can tell when I slug the barrel that the barrel is much tighter there. I haven't yet measured the constriction.

I understand that this is very common in non-pinned revolvers. I primarily want to correct the constriction for shooting cast lead bullets are moderate to high velocity. What are the different ways to deal with this?

Thanks,

-John

[irascible_joe]

The two most common suggestions seem to be fire lapping and having a Taylor throat cut in the barrel. Ross Seyfried discusses both options in this article. (http://www.gunsamerica.com/blog/ross-seyfried-lipseys-ruger-flattop-44-special-bisley-revolvers/)

[john c]

Thanks, joe, for the pointer.

Are there any other options?

[Malamute]

Thanks, joe, for the pointer.

Are there any other options?

Carefully hand lap it.

[Lester Polfus]

In practical terms, what are the consequences of this? Less accuracy? More leading? How big of a problem is it?

[john c]

One further question:

Are there any downsides to getting a Taylor throat?

[Malamute]

I hadnt heard of a Taylor throat before. I have a couple questions also. It seems to make sense that it could help if the thread area was tight. If its universally better, why dont any manufacturers use it, or why isnt it more common? Has anyone done comparisons with properly sized barrels/forcing cones rather than just tight ones? It seems like its more of a "fix" for a problem than the all around better way. I dont know though. It would be interesting to find out more about it.

There was a pretty good peice about fire lapping and hand lapping on the Los Angeles Silhuette Club site, but it seems to have disappeared. It was written by several guys that used different methods, how they did them, and the results. The one thing that stuck out in my mind, when hand lapping, stop AT the constriction, going past it when changing direction will make a large/loose spot where you change direction. I was trying to find it to let you read it.

Understanding it, and doing it correctly can yeild very good results, and it isnt difficult or complicated. Doing it incorrectly can cause problems. Same for fire lapping. Fire lapping may work for what you need to to, or fire lapping with the polishing media put in the bore rather than on the bullets.

Low velocity and low pressure I believe are whats called for.

[RevolverRob]

In practical terms, what are the consequences of this? Less accuracy? More leading? How big of a problem is it?

Both. Depends on how big the constriction is.

With cast bullets, that are not hard cast, at even moderately high velocity, you can get lead build up at the constriction. Theoretically, it could be a big enough constriction, that even with minor lead build up at it, you could end up with undersized bullets after the constriction. Of course those bullets will not be making good rifling contact and reduced accuracy results.

[okie john]

I have several revolvers (both Ruger and S&W) that have a noticeable barrel constriction where the barrel screws into the frame. I can tell when I slug the barrel that the barrel is much tighter there. I haven't yet measured the constriction.

I understand that this is very common in non-pinned revolvers. I primarily want to correct the constriction for shooting cast lead bullets are moderate to high velocity. What are the different ways to deal with this?

Thanks,

-John

I went down this road hook, line, and sinker about ten years ago. To greatly oversimplify things, you have to balance the gun's dimensions at the cylinder throats, at the forcing cone, where the barrel screws into the frame, and at the muzzle. There's a lot of wisdom about that here: http://www.angelfire.com/ga/alphaprecision/revolveraccuracy.html Also, the issues of endshake, headspace, carry-up, and alignment exist in a complex relationship to those dimensions, and they must all be brought into harmony to truly get the best out of a specific piece.

The main thing I learned is to listen with great care when people who profit from this kind of work tell me that my revolver needs X, Y, and Z done right out of the box, which can be like the Ice Cream Council telling you that your ideal body weight is 450 pounds. You can end up "correcting" things that aren't really problems and that don't increase performance in any meaningful way. So before you start cutting on your guns, shoot them and see just how bad things really are.

If you have several guns that each need $250-300 worth of work, it makes a lot of sense to sell some or most of them and have a full-custom revolver built in a versatile caliber. I've done that a couple of times, and the results are delightful.


Okie John

[1slow]

The two most common suggestions seem to be fire lapping and having a Taylor throat cut in the barrel. Ross Seyfried discusses both options in this article. (http://www.gunsamerica.com/blog/ross-seyfried-lipseys-ruger-flattop-44-special-bisley-revolvers/)

Seyfried is the go to source on big bore revolver !