S&W Model 66-2 .357 Combat Magnum issue

[BKG203]

When firing my S&W Model 66-2 using .357mag ammo, the cylinder will jam and not cycle to the next round. However, if I shoot .38spl or .38+P, it cycles just fine with no issues whatsoever. Anyone here had any issues like this? And of so, what was the fix?

Thanks.

[cmj0968]

Sounds like a pressure issue. I recently read an article on that very model that said to use only 158 gr loads. Something about the forcing cone? It also said that's why they don't make the K frame .357. Have you tried the heavier loads?

[Phillip Gain]

This might shed some light:

Is there a "best" S&W model 66 version? - THR

I'm no gunsmith...but this sounds like the problem you're having.

I bet if you sent it in to Smith & Wesson, they'd fix it for you for nothing.

[SingleAction]

When firing my S&W Model 66-2 using .357mag ammo, the cylinder will jam and not cycle to the next round. However, if I shoot .38spl or .38+P, it cycles just fine with no issues whatsoever. Anyone here had any issues like this? And of so, what was the fix?

Thanks.
Attachment 4615

I have a 686, and shoot .38's in it almost all the time. When I go to shoot .357's, they don't drop all the way into the cylinder, because there is a carbon build up where the .38 bullet leaves the cylinder. This maybe your problem. It's very hard to clean this out and this is why it's jamming, at least with my gun!

[Ronald]

Don't know if this is related but, had a S&W "scandium" .357 mag that used to hang up after 3 or 4 shots. Seems the bullets were extracting them selves from the cartridge as I was shooting. Could hardly ever make it to the 5th round! Had to look for ammo that was very well swedged so the bullet wouldn't "self extract". I got rid of it.
Ron

[BKG203]

I have a 686, and shoot .38's in it almost all the time. When I go to shoot .357's, they don't drop all the way into the cylinder, because there is a carbon build up where the .38 bullet leaves the cylinder. This maybe your problem. It's very hard to clean this out and this is why it's jamming, at least with my gun!

Thanks, but build-up is not a problem. This gun is impeccably clean and the .357's drop all the way into the cylinder.

[BKG203]

Sounds like a pressure issue. I recently read an article on that very model that said to use only 158 gr loads. Something about the forcing cone? It also said that's why they don't make the K frame .357. Have you tried the heavier loads?

Thanks. I am using 158gr SJHP's.

[BKG203]

This might shed some light:

Is there a "best" S&W model 66 version? - THR

I'm no gunsmith...but this sounds like the problem you're having.

I bet if you sent it in to Smith & Wesson, they'd fix it for you for nothing.

Thanks. I could possibly be the gas ring expanding, but it does it when it is first fired with .357's (gun is cold).

I think I am going to contact S&W and talk to a rep. Thanks for all the responses and suggestions from everyone.

[Phillip Gain]

I have a 686, and shoot .38's in it almost all the time. When I go to shoot .357's, they don't drop all the way into the cylinder, because there is a carbon build up where the .38 bullet leaves the cylinder. This maybe your problem. It's very hard to clean this out and this is why it's jamming, at least with my gun!

As an aside - those "rings around the chamber" clean up nicely with a bit of scotchbrite pad wrapped around a rod or dowel or something. Swab the chamber with some solvent first, let it sit a few minutes, and run the scotchbrite pad in. It doesn't have to be all that tight or anything, and it will scrub that ring right down.

This also works nicely on the carbon rings on the front face of the cylinder...but it can also take some bluing with it, depending on the gun.

[Phillip Gain]

I think I am going to contact S&W and talk to a rep. Thanks for all the responses and suggestions from everyone.

Their customer service is really good. My M&P 45 had an inoperative trigger when I first bought it. Even though it was a used gun, they replaced the entire trigger and sear assembly (which I suspect may have been aftermarket and improperly installed by an amateur) , cleaned it nicely, and sent an extra magazine back along with it. Turn time was maybe 2 weeks. And they didn't charge me a dime!