One of the blocks installed by BCM, not one you did yourself. Curious how they hold up over time and a few thousand rounds.
I have a few factory BCM 11.5 uppers in the 4-7k range. No issues. With the higher round count they become even harder to remove.
The carbon must cement them on there.
Good to know your experience. Thanks.
I’ve had two uppers with 2500-3k rounds on each, no issues.
Please tell me that this is some kind of cruel joke?
Actually I believe you guys (Sionics) use a similar technique from a conversation I had a while back with one of your people. It is simply a question regarding long-term/higher round count outcomes on gas blocks not pinned but instead dimpled, with knurled screws, and red Loctite applied. I’ve seen it mentioned here (likely as a matter of personal preference) that one’s “go-to” gun should have a gas block pinned. I figure if there are enough guns out there with beaucoup rounds downrange set up in the [properly] non-pinned fashion then pinning may not be a prerequisite for a serious duty weapon. BCM is the best large vendor example of this, although Sionics is also a good reference.
SOPMOD II rifles (10.3" and 14.5") see a fair bit of abuse and have set screw gas blocks.
I’ve wondered the same thing. Both my go to carbine’s uppers started as BCM’s with standard FSB. I ground and contoured them and painted before putting on a 12" rail. I went this route because I knew they would stay in place and just didn’t have enough experience with the others.
FWIW, from a conversation from Dave over at Defensive Creations:
Was the filthy 14 not set screw?
I think filthy 14 was an EAG upper with a fsb.
I’m honestly curious as well. It was common advice around here for a long time that a pinned gas block was the only way to go if you were going stake your life on a weapon. I figured things must have changed a bIt for low profile gas blocks covered by a rail given the prevalence of non-pinned gas blocks from BCM and others. But still, the gospel of pinned gas blocks is rampant.
I questioned set screw gas blocks, too, but I changed my mind after I saw this video from Mrgunsngear. He had a really hard time trying to remove the BCM gas block.
I suppose, as with most things, it really depends on the method used. I’ve seen several training AARs lately from people who had their set acrew gas blocks loosen up on them during class, turned my their guns into bolt actions. I don’t know who did the install, though.
I have a BCM factory built 11.5" ELW upper with over 3K on it. It has run so far w/o fail in temps from 25 degrees to 105 degrees. Run both suppressed and unsuppressed. Gas block is tight. No “hard use” though (i.e. combat conditions). I’ll can report back at the end of the year, as it should be approaching 5K by then.
NC
That would answer a lot of questions.
Oh yeah I think you’re right.
OP - I’ve got two BCM uppers, both with 2.5-3k rounds which isn’t a lot but I really think if there were issues, we’d have heard by now. BCM uppers are so prevalent that I have a hard time believing that their method doesn’t work.
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All set screw gas blocks are not created equal. Material, thread locker, depth of dimple, and fit of the gas block are all important in the security of it. Sionics and BCM have consistently the deepest dimples I’ve seen and I’ve removed 2x BCM gas blocks at this point in my life (never the Sionics) and it takes serious work to get them off. I’ve heard of people having to cut them off or send them to ADCO to get them removed…
So a properly installed, quality factory product (like BCM and Sionics that we know of), protected by a handguard/rail system, should be able to qualify as a weapon you could stake your life on?
My favorite AR has a 14.5" BCM ELW upper with 13" KMR (the original magnesium one), LMT Enhanced BCG, and Geissele SD-C trigger. It has the factory installed gas block under the KMR, so it’s protected. Since it’s my go-to (if you will) and it has other excellent enhancements I was just wondering about the utility of having it pinned. I don’t have a FA lower so it’s quite unlikely, even in a SHTF scenario, that I’d ever heat it up enough to undo the red Loctite. I’ve also just read about the depth of the dimples in Mrgunsandgear’s post above. It sounds like just about any torque strong enough to twist it would also damage or ruin the gas block. To render the gun inoperable by means of the gas block moving, given that it is protected too, would likely deadline the weapon anyway.
I understand the above comments, my doubt was in my ability to do it right! I know I can use enough hammer for taper pins. I have mounted a few for friends and no complaints but all of mine are pinned. I’ll try one for myself on my next build but ut will take a thousand rounds for me to feel as confident as I do with my pinned uppers.