Hi, I'm new to the AR platform and recently purchased a MP 15 Sport II. I'm having a problem with it cycling. It shot the first few shots with no problems but now it will shoot the first round and eject just fine but then on the next shot the bolt doesn't move. I manually eject the round and it will fire but not eject again. I noticed today that the first spent casing is warm to the touch like it should be but the next casings are cold to the touch. Does this make any sense at all?

I called the store I bought it from and they will send it off to be fixed but I thought if there was a simple solution I could try and save not having the gun gone for weeks then I would try it.

Thanks for any help you can give me.

Mine did the same thing when it was new. Just needs to be broken in a little. After I had a 100 rounds through it, it went away.

Sent from my SM-G935P using Tapatalk

Thanks for the quick reply.

I was looking around some more and found the pin that should hold the gas tube in place was missing. That allowed the gas tube to move back just enough to cause the problem. My temporary fix worked but now I need to get a "real" pin for it.

Yeah. I don't know that I would fire it until it'd fixed right!

Sent from my SM-G935P using Tapatalk

What you need to do is call S&W Customer Service. You bought a factory complete M&P 15-Sport 2. The biggest advantage of buying a factory complete rifle from S&W is the 1 year warranty and that S&W has the size to back up their warranty. Call them up. They'll send you a shipping label. Send it to them, they repair it, and they send it directly back to you.

What worries me is that if someone on the assembly line didn't install a gas tube roll pin, who knows what else could be missing.

__________________
-John

This is taken from a 4 year old thread when I had a problem with my new (at the time) Sport.

S&W resolved the problem but they NEVER told me what the problem was when they returned the rifle. When I called them there was no written explanation of what the tech. did to repair the problem.

Hopefully, you will be told what the problem was.
I have had no problem since.

Older thread below... "almost new m&p sport jamming" 3/25/12
I've been reading this forum and just joined today.
I have owned the M&P Sport since Oct of 2011 and after firing approx' 300 rds. of Lake City, Freedom Munitions and Remington I could not pull the bolt back more than 1/2" using the charging handle. I had to remove the rear pin and seperate the lower from the upper half and refasten which allowed me to fire a few more rounds and the same thing happened.
I sent it back to S&W and so far no problems.
I just wish they would state on the repair invoice the problem or at least what they did to repair, not even a 3 digit code that most companies use to distinguish the problem for tracking purposes. So far the Sport has worked fine and I am in NO WAY bashing S&W. They make great products and they stand by their warranty.
If any one knows what the problem could have been please share.