So, I shot my new M&P 15-22 for the first time today (along with my wife's 15-22 for the second time!). The action would NOT stay open after the final round with two different magazines...my wife's gun performed flawlessly.
Any experiences to share? Anything I should look for? We were both using CCI AR 22LR ammo. Just a newbie looking for direction here!
Thanks,
Dan

Does the bolt catch work manually?


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Let me add, a 66 year old "newbie" ( to the S&W M&P 15-22) with lots of experience with other guns...

Perfectly, no problems at all. We were both using CCI AR Tactical ammo.

I now have 5 magazines and will be trying them all within the next couple of days. Just wondering is anyone else has had issues.
Dan

Google search turned up this thread:

S&W M&P 15-22 last round bolt open


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Every round fired perfectly, just that the action didn't stay open after the last round...5 rounds, 10 rounds, 15 rounds, 20, 25 ...everything cycled fine but the last round did not leave the action open. ???

Will try some Blazers & some Mini Mags in the next week or so. I only have about 100 rounds through this rifle today. I'll shoot more before I panic.

Hey Dan,

The fix that uscav8r linked you to is the age old fix for this issue, which hasn't reared its head in a while.

Before you perform the fix though check your magazines. I recall that there was a recent batch that came out of the factory with the followers installed upside down. That would account for the problems you're facing. If the followers are correct then the T22 methods described in the linked thread will work to correct your issue.

1: Make sure you in no way hold/grip/rest on the magazine while firing.
2: Check your magazine followers.
3: Perform the spring clip fix in the thread.

Then start shooting happy again!

Quite familiar with the magazine issues, thanks. This is our second M&P and I tried five different magazines, both 25 round & 10 round...all the same. My wife's gun had ejection issues and mine has the action issue...and their serial numbers are only 18 numbers apart.
Spring clip fix, here we come!
Thanks all,
Dan

I have two of these rifles also. Fortunately mine have functioned flawlessly with any ammo. But if I ever have any problems whatsoever, I'll start swapping parts, since they're identical. I'd suggest that you do the same, to try and narrow it down. I'd start by swapping the bolt, since we can call the mag issue solved, in your case. If that works, then I'd start to narrow that down, till the culprit is found.