I am building my firs AR and due to the recent spike in demand I was not able to get the exact barrel I wanted. The barrel I did get does not have the cut outs, for lack of a better term, for set screws. For that reason I am looking at the clamp on style and was wondering how well these work.
I don’t recommend clamp on or set screw gas blocks. Buy a gas block and send it to ADCO for pinning.
Are you dead set on a gas block or would a FSB work? I have the A.R.M.S. #41b folding FSB on my M4 clone rifle and it clamps on.
Here is a link to where I got mine: http://swfa.com/ARMS-41B-Silhouette-Folding-Front-Sight-P40335.aspx
Stay away from clamp ons. You can send it to a shop like adco or rainier and get an FSB pinned.
If you’re not going to using the carbine at work, IE LEO, then having a pinned fsb isn’t going to matter a lot.
Clamp on type gas block/FSB’s are ok for a non work type weapon.
fair warning if you drop it on the floor the fsb “might” move.
My preferred is a low pro set screw which, if I choose, I can pin after I’m done fiddling with the setup.
Clamp type gas blocks/ front sight bases that I trust …
PRI
Daniel Defense
Demand the best whether you are LEO, Mil, or Civi.
Pin it, and don’t look back.
Send it to ADCO for a FSB, send it to Rainier if its a gas block you want pinned.
fair warning if you drop it on the floor the fsb “might” move.
This is reason enough not to go clamp on. Why bother with the possibility when a solution to never have to exists, and is easily attainable, at that.
Never cut corners when it comes to tools that weren’t designed for cutting corners themselves.
FSB - accept nothing less than pinned.
Low profile gas block - I’m ok with a quality clamp on such as DD or Vltor. Clean the screws and holes with acetone and apply Rocksett, then torque them down and witness mark them. In terms of lateral impact, I’ll take a properly installed clamp on over a set screw GB any day. Pinned trumps both IMHO.
Keep in mind, clamp on GBs protrude more at the bottom than other types, which limits the kinds of tube rails you can install (unless you grind them down).
Bravo company has their low profile gas blocks in stock. They are quality and come with hardened set screws that have knurled ends on them. Dimpling a barrel is really no big deal if you take your time and line everything up right before you drill. I wouldn’t use a clamp style.
If you are running a free-float railed handguard that covers a low profile gas block, pinning is great, but not required. I have used both set screw and clamp style LP gas blocks with great results. For those that poo-poo clamp on gas blocks, I recommend reading this, written by one of our Mods.
Vltor VST-1C Folding Front Sight Assembly Torque test
Thanks for the link to that test. I’d completely forgotten about it. It’s in my bookmark farm now.
How’s that? I’d figure that a bottom set screw gas block going onto a dimpled barrel would be less likely to move than a clamp on.
Rotational force, maybe. Drop it from chest height. Who knows… It may stay. BUT… It’s still a corner cut that, in my opinion, shouldn’t be.
Here is a little more info on what I want to do. I am building a carbine length AR and I want to use a free float rail that extends past the gas block. I am going to have a red dot for my primary sight and then a set of flip ups for my backup. This is not going to be work gun unless I need it to be.
I would also take a clamp-on GB over a set screw as well. The clamping force from 2 large allen head screws (in the case of my VLTOR) vs 2 small set screws is significant. Consider Loc-tite as well. If you’re freaking out or its a duty rifle pay the $$$ and get it pinned. The GB on my Noveske barrel is screwed and pinned - it isn’t going anywhere.
Any of the low profile gas blocks from Bravo company, Daniel Defense, or Vltor will work just fine.
If you do get a gas block with screws, use some loctite 2422 on them. It is very high temp and will not melt/burn up to 650*F.
I went “Clamp on” with my .330 Blk build, and so far so good.
I would have gone with Pinned but I just didn’t want to send it out.
I put a low profile clamp on block on my 5.45, wore out a barrel, installed a new barrel, wore it out, just installed the third barrel, no problems. After installation I shoot it a couple of hundred times, tighten, shoot, tighten, shoot again, it won’t tighten. I have checked the screws several times since, they won’t tighten any more. I did change the screws from hex socket head to a Torx socket head and replace the screws with each new installation.