AR - light primer strikes when bump firing

[solrac7]

OK Guys and Gals,

I have an AR pistol in 556 which shoots fantastic normally, but if I bump-fire it, I'll get light primer strikes occasionally. Is this a normal consequence of "bump-fire" or am I doing something wrong? Sometimes it will go 3-4 rounds without this happening, sometimes I can dump a full 20 round mag. I know this is not the way the pistol was intended to be used, but sometimes it's just so damn fun...

Cb

[dkf]

What trigger and trigger springs are you using?

[danhr]

Are you riding the bolt home?

[marinville]

Most likely you are just getting hammer follow from outrunning the max cyclic rate of fire. (Pulling the trigger before the bolt carrier completes its forward travel)

The firing pin floats, so any chambered round will have a slight indentation on the primer.

[dkf]

He could be getting bolt bounce also.

[Hawk]

He could be getting bolt bounce also.

I'm thinking this is not possible on a AR (with a locking bolt). Am I off base here?

[Hawk]

I'm thinking it has to do with how loosely you hold the AR when bump firing. Sort of like limp wristing a semi-auto pistol.

[dkf]

I'm thinking this is not possible on a AR (with a locking bolt). Am I off base here?

It is very possible on an AR. It becomes more of a problem as the rate of fire increases. In semi rifles the bolt has more time to settle down between firing if there is bounce. The BCG has to be completely in battery to get the full firing pin protrusion to hit the primer.

You can see the difference between buffers in this vid. Notice some have more bounce than others.

[Sgt.K]

It is very possible on an AR. It becomes more of a problem as the rate of fire increases. In semi rifles the bolt has more time to settle down between firing if there is bounce. The BCG has to be completely in battery to get the full firing pin protrusion to hit the primer.

You can see the difference between buffers in this vid. Notice some have more bounce than others.

[Hawk]

It is very possible on an AR. It becomes more of a problem as the rate of fire increases. In semi rifles the bolt has more time to settle down between firing if there is bounce. The BCG has to be completely in battery to get the full firing pin protrusion to hit the primer.

You can see the difference between buffers in this vid. Notice some have more bounce than others.

Hard tell if that's just the "bolt carrier" bouncing or the entire BCG including the "bolt". I'd have to check and see how much carrier movement I can get backwards without rotating the bolt.
All I can add is that the bolt has to be rotated in the lugs for the carrier to be that far forward in those video's.