Need help with new M&P 15-22 misfires
Folks, I need help diagnosing a problem with my new M&P 15-22. And I really want to get it working by April, as my daughter & I were planning to use this rifle for an Appleseed event. We've already signed up.
I’ve only had it a couple of months and have only taken it to the range three times.
The first trip went well. I shot using the 10 round magazine MD requires be sold with the gun in this state. I probably shot 3-400 rounds with only a few problems. I had a 3 or 4 failure to fires (round chambered and was rim-struck by the firing pin but it didn’t go bang.) But I know rim fire is less reliable than center fire plus the ammo I was using was neither on the good nor the bad ammo lists in the S&W manual. So I was happy and didn’t worry about it. Took the gun home, cleaned & lubed it, and put it away for a couple of weeks.
Saturday I took my 14 yo daughter and her friend, a first time shooter. I wanted to make a good impression on the newbie. It was not to be.
The M&P simply would not reliably fire. As before the round chambered, but when the firing pin was dropped we just got the dreaded click not bang. Sometimes round after round acted that way, other times we’d get one round to fire but the next wouldn’t fire.
I was using some new higher capacity magazines that I had gotten while out of state (which I'm allowed to do, for now) and I hoped the problems were mag related, since I had left the original 10 round at home.
So today I went back to the range. It was not the mags. It failed on all mags, including the original mag that once had worked well. Something else is wrong.
I could only establish one repeatable pattern, and even it was not 100%. And that is: If I loaded a mag, dropped the bolt and loaded one bullet, then ejected the mag before I fired, it would (almost always) fire. I could then pull the bolt & lock it back, reload the mag, drop the bolt to load one more bullet, eject the mag again & fire again. Essentially what I have is a single shot bolt action 15-22. Sigh. But if I left the mag in and dropped the bolt, the first bullet would fire, it would eject OK, the second bullet would be loaded into the chamber, the firing pin would drop but it would not go bang. Just click.
When I manually ejected the bullet I could see the firing pin strike on the rim. Yeah some of them might have looked a bit light but others looked almost as big & as deep as the ones fired. (I saved as many of the bullets/shells as I could.)
That was the usual pattern. Occasionally two other things would happen: 1) Once in a blue moon I wouldn’t even get the click. The firing pin was not reset. 2) Also once in a blue moon, it would go into true semi auto mode for short runs before it would eventually fail.
Ammo used was: Federal Champion 36 grains, Winchester Super-X 40 grains , Winchester 555 36 grains (white box), and PMC Zapper. PMC was the one that had the most semi auto runs, followed by Federal, but neither one would always work.
Here are the stats. I logged every shot including which of 3 mags I was using and which ammo. But these are the rolled up stats:
When the magazine was left in:
First round didn’t fire: 1
First round fired, second bullet fed into chamber, firing pin struck but didn’t fire: 23
First round fired, second bullet fed into chamber, firing pin not reset: 3
True semi automatic mode worked successfully, runs of length: 2, 2, 2, 9, 6, 2, 8, 2
When the magazine was ejected after the first round was loaded:
First and only round didn’t fire: 4
First and only round did fire: 28
Below please find photos of the end of some bullets. The first set is of the shells that did fire. The second photo is bullets that were struck by the firing pin but did not go off. It looks like a hard enough hit to me, but what do I know…
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