Short Stroking?

[Roger Ronas]

Took to new builds to the range today.
One in a 5.56 with 16" barrel, using SS109 62gr factory ammo it ailed to pickup another round or lock back on an empty mag.

Second build is a 300 Blk with 8" barrel. Using reloads, 168gr BTHP with H110 powder. Forget right now the charges but it went from the low to the high end and also same results. Failed to pick up a round from mag and failed to hold open on empty mag.

Lacking more details on builds as it's been a long day.
Just don't know if I need heavier or lighter buffer. Also what else to try/

Thanks
Roger

[Great-Kazoo]

correct recoil spring? Having an issue with 2 uppers on the same lower, points to buffer and or spring.

[ray1970]

I've had trouble getting a 16" 300 to run 168's with H110. Unless you were running a suppressor on that 8" barrel you might not be generating enough gas pressure with that load.

As as far as the 5.56, I'd look close at a gas port alignment issue or maybe gas leakage at the bolt assembly somewhere.

Those are my best guesses without more details.

Running a a standard spring and buffer will help with the 300 as well.

Good luck.

[sportbikeco]

Id check that gas port for alignment, or a chunk of slag in it off the first round fired.

[Roger Ronas]

Thanks for the ideas.
This is 2 complete builds not uppers on 1 lower. Was going to check port alignment and thru research may try an H2 buffer as well.
still confused on suppressor usage with 168gr if your velocity is super?

It'll be a couple weeks before I
can look at these as house guests have me backed in to a corner, roomwise.

Thanks again,
Roger

[BuffCyclist]

Can you provide details on the 5.56 build, as in buffer weight and gas length? That might help someone narrow it down a bit more.

[ray1970]

still confused on suppressor usage with 168gr if your velocity is super?

Sorry, your original post was really lacking detailed information. You did mention the 300 had an 8" barrel so obviously it is either a pistol or SBR. I just didn't know if you were running it suppressed or not. It will make a difference when it comes to cycling.

[cofi]

Gas length (carbine,middy,rifle)?
buffer system (rifle carbine a5)

what type of mags did you try other ones?

your post was the equivalent of going to the mechanic and saying I have a blue car that has a problem

[ray1970]

your post was the equivalent of going to the mechanic and saying I have a blue car that has a problem

He was a little more specific than that.

It was more like... I have a Toyota and it's making a noise.

[Great-Kazoo]

He was a little more specific than that.

It was more like... I have a Toyota and it's making a noise.

A whine, or scraping noise?