Adjustable Gas Block advice - AR-10

[Little Dutch]

First I'd suggest you take a close look at what's going on during the failures. Supressors tend to over gas actions when installed on normally functioning rifles. Failure to eject, in my experience, is from under-gassing or other issues. I'm not saying it's impossible that over gassing is causing failure to eject, it just tends to be lower on the list.

How many rounds thru it supressed and un supressed? Any changes? New ammo? What ammo? What is the ejection pattern change when you add the can?

It is fairly new still; I have less than 500 rounds through it total. However, it cycles 100% of the time with the suppressor off so it's likely the problems are caused by having the suppressor on, which points directly to being an overgassed issue.
No changes other than adding the suppressor. I am using the same Hornady American Gunner factory ammunition. I considered checking the ejection pattern, but it's hard to do at the indoor range because the case deflects off the divider wall immediately and I didn't think it worth the effort.

There are multiple types of FTE. So let's start with exactly what happens to the spent brass when it fails to eject.

Stovepipe- most likely overgassed as the brass did not have time to be flung out by the ejector while traveling rearward. It then hit the rear of the ejection port and was caught by the bolt on the way back onto battery.

Bolt override - worn or weak extractor or bad magazine pushing rounds off the bolt face before ejection.

Double feed with spent cartridge - bad ejector or a bad mag again or combo.

Spent cartridge rechambered - classic FTE short stroke from undergassing.

There are several more FTE failures. But most likely with a supressor, It's overgassed and has increased bolt speed rearward which can do all sorts of funny stuff, including stovepipe and doubles with spent casing in my limited experience.

I like superlative and seekins gas blocks. I've run JP, seekins, superlative and custom made for reference.

Thanks for the gas block opinions. I appreciate it. It's stovepiping the spent cartridge and jamming it up with the next round. It's extremely likely to be an overgass issue, because it cycles 100% of the time without the suppressor.

I went with the SLR adjustable on one of my 308 ARs. It's adjustable from the front via a long hex wrench.

Excellent, thank you. A lot of them I've looked at are adjustable from the side. I spent some time examining my hand-guard last night and I'm not convinced I'll have access to a side adjustment.


These Anderson adjustable blocks are discontinued and about half price right now. I am strongly considering taking a chance on one, because I like the price point and it's adjustable from the front.
https://www.opticsplanet.com/anderso...ock-ltica.html