M&P 357sig FTE

[SteelyNirvana]

Hi Guys,

Been a long time since I've been active here. I bought an unfired S&W M&P in 357sig last year. Finally got it to the range today. I was using Cor Bon 125gr JHP. First round fired and wouldn't cycle. Couldn't pull the slide back so I dropped the mag and still couldn't get the slide back. Asked RSO for help. He got it opened but really had a time with it. Second round same thing. Called their onsite gunsmith to take a look at it. He fired it and same issue. Had to drive the spent case out with a dowl. He took it back to look at it and asked if he could swap slides with one of their rentals the had chambered in 40 S&W. Same problem. Only explanation he could give me was the hollow point ammo but that doesn't make sense as it's an extraction issue and not a feed issue. I didn't have the money to purchase any FMJ ammo so I couldn't test his theory.

Has anyone else had this issue?

 

[redneck]

Assume he swapped the slide and left the barrel so he could rule out the extractor. To me that says you probably have an issue with the barrel. I'd check that the chamber is clean and smooth and that cartridges will drop in and out freely.

 

[trackskippy]

Kind of sounds like the chamber might be rough or out of spec.

Isnt Cor Bon ammo a bit warmer than most standard grade ammo too? If the chamber is sketchy, I think that would just add to things. Or maybe there's something up with the ammo and its way over pressure. Maybe a combo of both.

I agree with redneck, check the chamber is smooth and polished and do a drop test with the ammo you have and make sure its chambering properly. It should just drop in and fall back out.

If you couldn't get the slide open, Im assuming the extractor is working. If the case was stuck, and the slide could be worked, the case probably has a tear in the rim, and that would point to the barrel and/or ammo.

 

[Elkins45]

I’ll echo what the others have said. It sounds like the chamber has some rough es or flaws that are causing the case to get locked in place when it swells after firing. Swapping slides to use a different extractor with the same result adds to the evidence of a bad chamber.