Can't get bolt to lock back after final round BCM 9" 300 blk with MVB PDW stock

[Clint]

Thank you. I only have 300 or so rounds through it. Maybe it will work it’s way through. Of note this has happened with multiple different magazines. So I don’t think it’s a mag issue. I think the cycling is actually too fast and doesn’t allow the follower enough time to stop the bolt. MVB makes many different buffers so I have an email out to them for advice too.

Cyclic too fast is a definite possibility, especially with a suppressor.

But first, with the non standard MVB buffer, the static stroke should be checked to ensure the bolt goes ~.25" past the bolt catch.

Then start looking at dynamic issues such as mass, gas and spring force.

[cpoth]

Just to update and thank all who have shared info. I have discussed case w MVB they agree and suggest H2 buffer. Will report back when I get a chance to try it out.

Thanks again.

[cpoth]

I want to follow up and thank everyone. My bolt locks back on last round with all three listed rounds from the original post. I used the MVB industries bolt, added the heavy weight from a spare H2 buffer (which is what is in their proprietary H2 buffer) and it runs without issue through approximately 200 round test.