ZM weapons LR-300 SBR overgassed

[Gunslinger55]

So this is a weird post as most people are not familiar with Al Zittas delayed impingement gas system. It is similar yet different then a standard M-16 gas system and allows to fire with folded stock. When I SBR'd it back in the day it came with 3 recoil springs to tune as that apparently is the only way to do it. Well I seem to remember it running like a top and never having any problems.

Fast forward: Now it appears to be chronically overgassed. Case fly straight forward and goes bolt over brass regularly with resultant jam. And you can feel it when you shoot. When bolt hold open engages the charging handle is blown back due to the violence of the bolt travel. I tried all springs and ammo combinations and found the weak radway green ss109 ejects 3-4 oclock and seems somewhat reliable with I think the medium spring.

In any case I took it part and the bolt itself was pretty worn out but gas rings ok. Since there is no buffer to adjust there is not much you can do. The bolt carrier is lightened quite a bit which explains it velocity. I put a new bolt in it and basically same result.

Unable to contact Zitta for suggestions. But since this is such a cool gun I want to get it to run properly. The only thing I can think of is to modify gas rings or possibly delete one and see if more blow by will occur and reduce the gas. Must have a big port in that 11.5" Barrel.

Anyone familiar with the LR-300? Anyone have Zitta on speed dial? Anyone run a bolt with 2 gas rings?

TIA

[delta6]

Try Aldo on Facebook?

[Gunslinger55]

Sent Zitta a message.....again

[Gunslinger55]

While drinking beer I think that I could tune it by increasing gap of bolt rings to carrier by filing around rings on bolt take a tiny bit off. And if too much easy to replace. That would be similar to adjustable gas Block...

[Gunslinger55]

ok so update. Bad bolt. JP enhanced seems to have cured the issues.....