Amassing parts for my next Toy. I am handy enough that I have assembled several AR's without complications. Looking at gas block attachments there are two camps. Set screw and Clamp-on. I prefer the set screw but can't say why. Got to wondering if one was better than the other. Does clamp-on blocks have any advantages over set screw ? or vise versa ? Anything beyond personal preference ?
Supposedly set screw type can impart stresses at the points of the screws. Supposedly the clamp on blocks seal better without the point stresses. I've yet to see a problem with the set screw type and all my uppers wear them since they are cheaper. On the upside the set screw type are easier to align with dimpled barrels.
On every question of construction let us carry ourselves back to the time when the Constitution was adopted, recollect the spirit manifested in the debates, and instead of trying what meaning may be squeezed out of the text or invented against it, conform to the probable one in which it was passed.
Thomas Jefferson, letter to William Johnson, June 12, 1823
I prefer the clamp on as the above stated the better seal. Also I find they don't "walk" as much when tightened. I have seen set screws threads and tight fitted pins cause tight spots in bores from over tightening. I think the clamp on is easier to position. I made my gas blocks and they are clamp on and the gas tube is clamped in now pins or set screws, makes alighning the port hole easier. set the block in place and the shank of a fitting drill in the gas port hole and I can see the alighnment and move accordingly.
ive got both, and have never had either move, or leak.
None of mine have moved, or maybe I should say I've had no problems with them so far. I always thought they would both leak a little tho. Never worried about leaks cuz a gas port IS essentially a "controlled" leak. It's just got to be kept under control.
I appreciate your thoughts, I was just wondering if anyone with more Gunsmithing experience than me had thoughts on which is better or easier. The set screw has worked for me so far so I probably wont be trying to fix it anytime soon.
Sure wish I could make my own like C G.
i dont know so much that one is better than the other, maybe a clamp on has a slight theoretical advantage if it matches the barrel contour properly. as for ease, set screw gas block is much easier to get aligned, though with a little patience and thought a clamp on isnt very difficult to install in the proper place and straight.
Nun2kute Making your own is fun, satisfying and saves some money ( sort of like reloading goes LOL). When I did mine in the 80s parts were nearly as available, or as many selections. Most for a flat top match rifle just cut the top off a AR service rifle sight base for the gas block. The drawback to making your own really draws a build out time wise.
Set screws will not impart anymore stress than the original taper pins plus gas port to gas block alignment is generally straight forward as the dimple in the barrel aligns the set screw in the gas block for proper alignment which is much more accurate than the guess thats close enuff with the clamp on type gas blocks
I keep kicking the idea of getting a bench-top lathe for my garage, to make some of the easier things, but at this point I think it's gonna be cheaper to just buy parts and assemble them. (call it a "Build" hehe!) I'm having a ball as iit is. I just never seen any discussion bout gas blocks and why one person clamps or set screw's. I'm gonna have to try a clamp on now just to see what the difference is.
They also make a "bomb proof" gas block that uses both set screws (and you can dimple) then a roll pin across the underside.Originally Posted by nun2kute
https://d524kaacpo0h1.cloudfront.net...s_block_01.jpg
I might give them a try on future projects. I really like the idea.
Both ends WHAT a player
No problems at all with the set screw type. I see no reason to use any other type IMO.
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Also maybe something to think about, the military design that used the taper pins also asked the gas block/front sight base to act as a place to attach and use a bayonet too.
Bill
Both ends WHAT a player
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