Set Screw Versus Clamp On

[mineralman55]

It's fun, but it's also tedious to consider all the many choices necessary in building a 308AR. I'm in the process of selecting a gas block now. Two major methods to attach the gas block to the barrel are set screws and clamp on. I've read where people worry about using set screws because they'll loosen up, or dimple the barrel or distort the barrel. Has anyone actually had mounting problems with the set screw models?

 

Also, do adjustable gas blocks actually add anything to the game? I'm not planning on running a suppressor, so that's not in play.

[blue109]

I went with set screw because my barrel was dimpled. A side bonus is knowing the gas block is completely straight and correctly positioned (assuming you trust the dimple and screw location)

Edited August 16, 2013 by blue109

[planeflyer21]

I went with a clamp on for my first LP gasblock, because it looked just a bit cleaner than the others I was looking at.

[michael1778]

Dimensions are sometimes different between the styles, even with the same manufacturer.  Have you selected a hand guard yet?  Certainly you need to make sure you have enough room inside for whatever style of gas block you choose.  This dimensional constraint will push me to set screw for the vendor I want, for example.

[Matt.Cross]

It's fun, but it's also tedious to consider all the many choices necessary in building a 308AR. I'm in the process of selecting a gas block now. Two major methods to attach the gas block to the barrel are set screws and clamp on. I've read where people worry about using set screws because they'll loosen up, or dimple the barrel or distort the barrel. Has anyone actually had mounting problems with the set screw models?

 

Also, do adjustable gas blocks actually add anything to the game? I'm not planning on running a suppressor, so that's not in play.

 

 

Adjustable GB can keep you from experiencing overgassing at the user end. May not be a problem at all, but you might stumble upon a particular load that sends lots of nice smelly gas out of your ejection port on every shot.....

[survivalshop]

The clamp on type tend to be a little taller on the bottom clamp area , But pretty much, they are all I use.

[mineralman55]

Dimensions are sometimes different between the styles, even with the same manufacturer.  Have you selected a hand guard yet?  Certainly you need to make sure you have enough room inside for whatever style of gas block you choose.  This dimensional constraint will push me to set screw for the vendor I want, for example.

Not selected a handguard yet. My SI upper is the older "high profile DMPS" style, and I am trying to ensure a single top rail is compatible with it. Some aren't. I'm leaning towards the Rainier/Troy .308=TRX rail or a Samson rail if it's rail height compatible. Most low profile gas blocks of either clamp or set screw seem to fit inside these.

Edited August 22, 2013 by mineralman55

[Zebra644]

I went with set screw because my barrel was dimpled. A side bonus is knowing the gas block is completely straight and correctly positioned (assuming you trust the dimple and screw location)

^^^^^^^

Nothing wrong with a clamp on either a litte blue lock-tite and your good.  IMHO an adjustable gas block is only good for those who reload and for suppressor use . Remember the more stuff you add or tinker with can affect reliability.  

[Matt.Cross]

On the thicker barrels it doesn't really matter so much, but there are some experts who feel that an overtorqued set-screw type can affect accuracy... That's FWIW and YMMV...

[mineralman55]

So far, I'm not hearing any problems with movement by either set screw or clamp on types of gas blocks. That's good.

[Magwa]

I have used two armalite clamp ons with zero issues....

[FaRKle!]

 

Also, do adjustable gas blocks actually add anything to the game? I'm not planning on running a suppressor, so that's not in play.

 

An adjustable gas block will also allow you to tune the recoil impulse of the rifle by adjusting the gas instead of buying heavier buffers and stronger springs.

[Robocop1051]

Choosing an adjustable gas block vs a heavier BCG/buffer assembly, is like arguing about front wheel drive vs rear wheel drive. Both have functions and purpose behind their designs.

[98Z5V]

So, it's like comparing Apples to Hammers... 

 

 

 

<laughs>

[Robocop1051]

So, it's like comparing Apples to Hammers...

<laughs>

Yeah... Pretty much

[Justintoxicated]

I have had set screw types leak, or loosen up over time.  I prefer the clamp style.  That said not all set screw blocks are equal, and sometimes the clamp is too big to fit.  For example I could not find an adjustable clamp together block for my .936 diameter barrel that would fit under my free float tube.  If I had the choice I would have gone with syrac clamp block though instead of the wilson combat block i am using.