S&W model 15-3 frame choke?

[slips73]

Does anyone have any knowledge with the idea of frame choke? Id never heard of it till i noticed a faint ring in my barrel right where the frame/threads meet the barrel. I cant really see it from the forcing cone end but from the muzzle end with a good light i can make out a very faint ring, I know its not from a squib and the gun has not been fired much. Only thing i can think of is frame choke/ thread choke from the barrel being pressed in. The barrel is pinned if that makes a difference.

Will this affect accuracy, durability or any of the sorts? What does it do to the gun functionally?

thanks,

Adam

[dubber123]

The barrel is very thin at that point, and when threaded in, it can leave a constriction. The pin is just S&W's older manufacturing method, it doesn't really change much. Functionally it does nothing bad really, but thread choke is a common cause of leading, as your boolit is squeezed down to this smaller diameter, and then it's snug fit to the bore is lost for the rest of it's trip down the barrel. Degraded accuracy usually comes as a result.

I have a lot of S&W's and it is a pretty common issue, as it is with most brands. Do a search on the site for "Firelapping". It's not hard to do, and I have had exceptionally good results from the process. It's inexpensive too. Good luck.

[slips73]

I have heard mixed things on firelapping, but it seems if at low velocity with plain lead it will only wear the high spots?

[dubber123]

I have heard mixed things on firelapping, but it seems if at low velocity with plain lead it will only wear the high spots?

Sorry for the late reply. Yes, the high spots go first, and you will find 99.9% of the naysayers have never tried it. I use air cooled ww's, and 320 grit valve grinding compound from the auto parts store. Before you proclaim the grit too aggressive, realize it breaks down to finer almost instantly. Your barrel will shine like never before. I have done quite a few, and always netted a noticeable improvement, often dramatic. Not in one single instance have I had a negative result.

It doesn't happen in a few shots, so if you are nervous, shoot 6, and check, shoot it with regular loads, ponder it over, whatever. You can do the process slowly over however long you want. The barrel and cylinder should be cleaned every 6 rounds anyways. I wish you were closer, I'd be happy to walk you through it.

Of the S&W's I have done, (including my most accurate M14), I totally eliminated leading at the breech end of the barrel, and knocked close to 50% off my 50 yard groups. If you have any specific questions, shoot me a PM, and I would be glad to help. Have fun!

[MtGun44]

If you unscrew the bbl, trim a couple thousandths off the shoulder and reset
with red loctite and the problem is solved. Need a gunsmith or need to be
a good pistolsmith yourself.