Home Forums Hunting & Shooting AR and Tactical Rifles Adjustable Gas Blocks

Clamp on vs set screw- any thoughts?

Thanks,
Rob

My favorite was Syrac, but I think they went tits up. SLR or Superlative Arms would probably be my next choices.

1. Make sure it is front adjusting
2. Detent locking adjustment (ball and spring) is more convenient than having a separate locking screw.
3. Steel, not aluminum.

I've got SLR adjustables with set screws so that they would fit under slim handguards.

SLR's clamp on's will fit under slim handguards too.

MM

But set screw vs clamp on, what's the advantage or disadvantage either way? They both appear to be the same price. It's hard to imagine one is significantly better from an accuracy standpoint. So is one better from a usability standpoint?

Sometimes the barrel is dimpled opposite the gas port to accept and align the gas block set screw. The clamp on variety don't require the dimple, just careful alignment. I've used both with no real difference in usability. Just check the gas block diameter when ordering to make sure the block will clear the handgaurd.

some folks claim the set screw variety will induce a stress point on the barrel , thus in theory possibly reducing accuracy


so Ive used the clamp on style for applications where I am looking for extreme accuracy , but Ive got no proof the theory is correct.........

That doesn't surprise me, those guys seem to put lot of thought into detail.

I was mainly interested in the titanium. And one of them is on a .458 SOCOM, I'm thinking the dimple will help keep it in place under recoil.



But, you have no nagging doubt, either. Peace of mind is nice.

The set screw style doesn't require a barrel dimple either, it's just a convenience for aligning the gas port.

In my experience it really doesn't matter either way. Set screw or clamp on both work fine if they are made well.

Oh, and I much prefer a side-adjusting gas block, especially when using a long handguard. I don't like the front adjusting style at all in those cases.

I have one on a WOA .223 Wylde barrel without the dimple, it has worked just fine.

For those who have used the titanium gas blocks, I read that titanium expands slower than steel, which would make the seal tighter as the rig heats up. That's a good thing, but after many heat cycles, I wonder if the gas block loosens up?

Good question. It really just depends on the amount and difference of expansion, and whether it caused high enough stress to matter. We could calculate it, but in reality I don't think it's a problem.

I have no problem using some sort of locking agent (Loctite, Rockset, etc) under the gas block if there's any doubt. They suck to remove later, but it can be done.
Usually with a set screw gas block (that's mostly what I use) I'll put a big drop of Loctite 243 in each set screw hole after the block is on the barrel. Installing the screws squeezes it out between the block and barrel, and I've never had one loosen. I also don't get my barrels smoking hot though; they'll get too hot to hold but not hot enough to break down the loctite.