FTF with first round in a new mag

[gunclinger]

Has anyone else seen this? About once every 10 mags I shoot, I get a Failure to Fire on the first round.

Right before this happening I've gone though the previous mag, so the bolt is open and the charging handle is slack. I insert the new mag, give the handle a pull back, and sling it forward to be sure it cycles well and loads the chamber. The cycling always appears to work OK. Then I take aim and shoot, but no bang. I eject the "live" round, and the rim is clearly dented, although not as deeply as on the casing of a successful round. (The rounds are never duds -- I try them again and they fire every time).

So it appears to be a not-strong-enough hit on the rim for this first round.

 

[chuck s]

Are you releasing the bolt or easing it shut where it may not be completely in battery.

-- Chuck

 

[gunclinger]

Has anyone else seen this? About once every 10 mags I shoot, I get a failure to fire on the first round.

Right before this happening I've gone though the previous mag, so the bolt is open and the charging handle is slack. I insert the new mag, give the handle a pull back, and sling it forward to be sure it cycles well and loads the chamber. The cycling always appears to work OK. Then I take aim and shoot, but no bang. I eject the "live" round, and the rim is clearly dented, although not as deeply as on the casing of a successful round. (The rounds are never duds -- I try them again and they fire every time).

So it appears to be a not-strong-enough hit on the rim for this first round.

Failure to FIRE is the issue

 

[E6type]

OK, I don't think you are using a preferred method of chambering that first round. Try this:

1. Pull the charging handle back while depressing the bolt catch lever, locking the bolt to the rear.
2. Place charging handle back to the forward position.
3. Insert loaded magazine.
4. Release the bolt by pressing the bolt release.
5. After the last round is fired the bolt will remain open.
6. Insert new magazine and release the bolt by pressing the bolt release again.

Trying to manually "slingshot" the bolt into battery does not have the same amount of force as by simply hitting the bolt release.

 

[chuck s]

This appears to be an ammunition issue as we all know the M&P15-22 will fire even with the bolt partially open. The cartridge is held against the bolt face by the extractor firm enough the firing pin will detonate the primer with the bolt partially open.

What ammo are you using?

Could also be a "crud in bolt" issue.

-- Chuck

 

[gunclinger]

What ammo are you using?

Could also be a "crud in bolt" issue.

-- Chuck

Federal American Eagle.

 

[gunclinger]

OK, I don't think you are using a preferred method of chambering that first round. Try this:

1. Pull the charging handle back while depressing the bolt catch lever, locking the bolt to the rear.
2. Place charging handle back to the forward position.
3. Insert loaded magazine.
4. Release the bolt by pressing the bolt release.
5. After the last round is fired the bolt will remain open.
6. Insert new magazine and release the bolt by pressing the bolt release again.

Trying to manually "slingshot" the bolt into battery does not have the same amount of force as by simply hitting the bolt release.

I'll try this method, too. I would expect the bolt releases with the same force in either case, but it could be that with the "sling" method the bolt slows while it kind of pulls the charging handle along. And some oil in the mechanism may help.