Yes, you should drill dimples in the barrel, and no, Locktite blue won't work

[Alpha2]

The new lo-profile gas block worked loose today, first time out, so apparently it's true that a couple dimples for the set-screws in the barrel, and red locktite or similar is required.
The funny thing is...it worked loose between factory loads and some new handloads. So naturally, I figured I needed to up the load a bit for proper action. Nope. Went back the factory and they failed to fully cycle also.

Some things you just have to prove to yourself.

[ray1970]

I prefer to pin the low profile gas blocks either in addition to or instead of the set screws.

[Alpha2]

That would be my preference, but this gasblock has two set-screws, and I've never pinned one. I assume that's the drilling a groove in the bottom of the barrel for a pin, and if so, what do you use for a guide? How far into the barrel? The screws looked easier, obviously, but if I can't trust them...

[ray1970]

They make jigs for drilling the pin hole. I don't have one yet. The last couple of barrels I bought came with the gas block and barrel pre-drilled for a pin. They also sell gas blocks made to drill and pin. They have a little flat area where you drill them.

[kwando]

Yup I've had one work loose as well... I just shaved my FSB down to fit under the FF rails. That is the most secure method

[MarkCO]

Just say no to set screw gas blocks. A properly installed pinned block will leak less and will not move. We came up with a side clamp style that leaks less, is very durable and won't move if installed correctly.

[ChunkyMonkey]

Throw away your gas block, get a stock FSB..and dremel OR Call Bert.

[Alpha2]

I can't believe I forgot about cutting the original FSB down. It was a RRA from the original mfgr. It had a two-screw clamp style that never loosened. That's still an option, but I already drilled the dimples when I got off work today, and used high temp loctite type stuff. (other brand though)
I'll try a few thousand rounds and see what happens, if it loosens, I'll cut down the original.

MarkCO, you're on the short list. Pics?

Thanks for all tips, guys!

[MarkCO]

Carbon Arms Gas Block

42651

[J]

I have 5 low pro steel gas blocks. All properly installed. Probably 50,000 rounds total on them. The most used one had probably 20k rounds through it. No issues.

I call hokum on low pro gas block inherent issues, so long as they are a quality steel gas block and installed correctly.

[Alpha2]

Thanks Mark.
I don't think they have "inherent" issues, I just got lazy and didn't install it properly. My bad, and I fixed it. I will keep a closer eye on it for the next few hundred rounds, though.

[TheBelly]

Just say no to set screw gas blocks. A properly installed pinned block will leak less and will not move. We came up with a side clamp style that leaks less, is very durable and won't move EVEN IF YOU'RE A MORON AND CAN BARELY OPERATE A COFFEE MACHINE, LIKE THEBELLY.


FIFY


Seriously, though. I cannot say enough good things about MarkCO's block.

[BPTactical]

Dimpled or non dimpled makes no difference. I have installed dozens upon dozens with no failures and that includes some pretty high end builds that get run very hard. The only time I am adamant about dimpling is with a Melonited barrel, that outer skin is so hard a set screw will not get a good "bite" into the barrel unless you get through the Melonite.
Correct installation is key, make sure everything is clean and dry, I give everything a bath in acetone or lacquer thinner prior to assembly, including the barrel.
A drop of RED Loctite in each screw hole and with a good quality Allen wrench torque them down to where the wrench deflects about a 1/2" or if you are torquing them 45-55 in/lbs.
Use good quality set screws, often the ones included with the block are garbage. You want serrated, cup point set screws. They really dig into the barrel well and the serrations act like a toothed lockwasher.

[ray1970]

The set screws really do hold pretty tight if done properly like Bert mentioned. We have applications where set screws hold hundreds of pounds of weight on a shaft that runs in a vertical position with no problems.

[BPTactical]

The set screws really do hold pretty tight if done properly like Bert mentioned. We have applications where set screws hold hundreds of pounds of weight on a shaft that runs in a vertical position with no problems.

Yup, we used to repair porcelain /clay mixers for Coors that were 2.5" shafts run by 50hp motors that the only thing that transferred the torque to the paddles were 3- 1/4x28" setscrews. They would mix about a ton of clay at a time and while the shafts would twist, paddles would break the set screws never let go. They held when keys would shear.

[brutal]

Granted, it hasn't seen thousands of rounds, but I put a BCM LP block on a BCM upper after removing the FSB and there hasn't been any issues. Pretty sure I used rockset on the screws since i was installing some QD mounts around the same time. They bite into the barrel where the FSB pins were.

P.S. Not saying it about anyone here, but people on the intarwebz complaining about BCM FSB pins being too hard to get out are probably the same people that have trouble with the FSB. Some folks are handy, some are handicapped.

Or as Red Green always says, "If the woman don't find you handsome, they should at least find you handy."

[Alpha2]

I put about 5 mags through the AR last weekend, gasblock is still in place. So, dimples, Vibratite or whatever it's called seemed to do the trick. I WILL be watching it closely for a while. Got the 1-4x scope dialed in pretty good. Last 3 shot group at 100yds was one ragged hole. Wahoo!

[vectorsc]

rocksett is great if you never want to remove it again. However, I have used loctite red quite a bit and it seems to hold. It is also possible to stake some set screws.

[brutal]

rocksett is great if you never want to remove it again. However, I have used loctite red quite a bit and it seems to hold. It is also possible to stake some set screws.

That's just simply not true. Rocksett is water soluble and can be removed if needed.

[TheBelly]

rocksett is great if you never want to remove it again. However, I have used loctite red quite a bit and it seems to hold. It is also possible to stake some set screws.

False. I just removed a brake that had rocksett on it. Using my arms and fists.

[Grant H.]

One more vote for just doing it right.

I've got more than a few low-pro set-screw gas blocks, one of which has seen 30k+ rounds and I have never had a problem.

I didn't even use loctite. Just buy quality parts and torque them down properly...

[Alpha2]

Update...
After a long range session, and a 3gun, the dimpled/vibratited (ha!, I knew the spell checker wouldn't like "vibratited"!!!) is holding fast. I still will check it for another few million rounds, 'cause that's how I roll. I'm not retentive, or obsessive, I just like to do things over and over and over and over again and again and again. Really. It's cool.