Overgassed or Undergassed? Or just right?

[MikhailBarracuda91]

I've read here that a forward ejection pattern can sometimes be caused by the extractor spring. Do you have another spring, or bolt to try?

I read that as well, so I changed the extractor spring and ejector spring to a springco set in that LMT BCG and it was the identical results.

However, my brother has a LMT enhanced BCG in his M4 and that thing throws cases at darn near 5:00 into the neatest pile I swear lol

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[DefenderAO]

Which Griffin can?

Their M4SD-K can. As others are pointing out it may very well be a bolt extractor. Round count is around 250 at this point so a bolt swap is still in play without any headspace risks

[DefenderAO]

Triarc told me themselves that it is 0.045. Perhaps that has changed. Parts would wear leas quickly with a properly or conservatively ported barrel such as yours. Your rifle seems to be functioning fine.


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I’ve gotten two different answers calling them. One was .048 and the other .046. The former was from a guy apparently who makes the barrels. Probably safe to say .045 - .048. I haven’t put it to rest by measuring

[1168]

Their M4SD-K can. As others are pointing out it may very well be a bolt extractor. Round count is around 250 at this point so a bolt swap is still in play without any headspace risks

Its a gassy can. I have one. It seems above average on gassiness, which is probably why it sounds as good as many full size cans. To be fair to it, most of my rifle can experience is with military cans and 7.62 cans. It and my Turbo K are my only 5.56 K cans, and they both work shockingly well.

The headspace is probably fine.

Many companies, including high end ones, use lame extractor springs sometimes they go unnoticed, sometimes they don’t. I only use Colt and the Sprincos that Iraqgunz (of Sionics) recommended. Mistwolf has some good rants about extractor springs and ejection, if you want to go through his post history.

[Clint]

Have you actually pin gauged your barrel?

It may be possible it has the normal port instead of the suppressed port.

.048 yes. I have read Triarc is .046 to .048. Either way I have not read of a smaller port size. BCM is something like .076, DD .069. I’m concerned parts may wear faster than needed and, when they do, best case is bad ejection become more pronounced and worst case, failures.

Here is another good clue.

Try swapping the BCG to see if anything changes.

My LMT (non enhanced) BCG does the exact same thing. It ejects spent cases to 1:30, when I switch it out to a BCM BCG it throws the cases to 4:30.

Chris Bartocci form Small Arms Solutions says LMT designs their weapons like that. In my experience it's the BCG's

[DefenderAO]

Have you actually pin gauged your barrel?

It may be possible it has the normal port instead of the suppressed port.

Here is another good clue.

Try swapping the BCG to see if anything changes.

I may swap the bolt vs the entire carrier. I bought some extra LMT and other mil parts post Sandy Hook and, frankly, I can’t tell them apart now. I will say the extractor retention pin is fairly easy to put in after cleaning. To me that would mean the tension is low and not a Herculean extractor trying to shoot brass through dry wall.

I’d be pretty shocked if Triarc gave me a wrong order. I may try and shoot it without the can. The Griffin van is a gassy one so it may just be the back pressure is that high.