Gas blocks. pin on or clamp on?

JTF#

JTF#

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whats the difference between the clamp on and pin on gas blocks? is one beter then the other?
only thing i read about was some times pin on type are a little tight to put on the barrel and you might have to sand them?
 
Pinned GB are generally a better bet. Pins tend to stay in place as the barrel is drilled for them. Screw/clamp on GBs run the risk of the set screws backing off and the gas block losing its seal or moving in general.

Pinned for the win. Screwed if you have to(or clamp if you can't).

TDC
 
You can try one of our designs currently being sold by S&J Hardware. The gas block is held on with set screws and when you get it all dialed in and shooting the way you want it to, there is a hole pre-drilled as a guide for a taper pin. You just drill out the hole and ream it with a taper reamer to fit the supplied taper pin. Can be done with a good drill press, but we recommend having someone do it for you that has the proper tooling.
 
Taper pinned is the best mounting solution. It will never come loose and never move.

Clamp on (single piece "squeeze" type, NOT two piece) is the next best. A properly made and installed clamp on type gas block will break the receiver before it turns on the barrel. If seen tests where they put a snipe on the block and it just twisted the receiver.

The two piece clamp-on style, that work like scope rings, should be avoided. Too much chance for fit error. The set screw type that rely on set screws pushing against the barrel should only ever be used as paper weights.
 
Armedsask said:
Dimpled or not, it's still an inferior option.
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Fail! Assuming that the gas block it well made from high quality steel and to tight tolerances to the barrel and that the barrel is dimpled or has a flat cut so that the screws can not rotate.
Our gas blocks employ 3 screws on the bottom and have ZERO leakage and having sold several hundred have yet to have any sort of problem, failure or mishap.
 
Allen Gun Works said:
You can try one of our designs currently being sold by S&J Hardware. The gas block is held on with set screws and when you get it all dialed in and shooting the way you want it to, there is a hole pre-drilled as a guide for a taper pin. You just drill out the hole and ream it with a taper reamer to fit the supplied taper pin. Can be done with a good drill press, but we recommend having someone do it for you that has the proper tooling.
Click to expand...

The S&J Low Pro is definitely affordable. I am planning on a Low Pro purchase as a backup. I am going to mutilate my pre-existing sight to create a Low Pro Gas Block and need the back up just in case my superior dremel skills fail me.
 
alberta tactical rifle said:
Fail! Assuming that the gas block it well made from high quality steel and to tight tolerances to the barrel and that the barrel is dimpled or has a flat cut so that the screws can not rotate.
Our gas blocks employ 3 screws on the bottom and have ZERO leakage and having sold several hundred have yet to have any sort of problem, failure or mishap.
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I didn't say they don't work, I said they are inferior to taper pinned and one piece clamp on.
 
Actually, many Engineers will tell you a one piece set screw gas block that is a press fit, is just as good and in some ways better than taper pin.

I've had clamp blocks rotate on me, and I'm not very jazzed on them.

My personal feeling is taper pin is superior.
 
KevinB said:
Actually, many Engineers will tell you a one piece set screw gas block that is a press fit, is just as good and in some ways better than taper pin.
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I agree. I should have clarified that I am referring to the slip on style that users would install themselves.

Of course press fit would be superior.
 
KevinB said:
Actually, many Engineers will tell you a one piece set screw gas block that is a press fit, is just as good and in some ways better than taper pin.

I've had clamp blocks rotate on me, and I'm not very jazzed on them.

My personal feeling is taper pin is superior.
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Agreed Kevin

Taper pins are best and second is the clamp style

The grub screw mounts are pure crap IMO and I would never put them on any of my guys guns
 
Dsiwy said:
Agreed Kevin

Taper pins are best and second is the clamp style

The grub screw mounts are pure crap IMO and I would never put them on any of my guys guns
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That is a pretty large statement considering in all types it really depends on how the device is manufactured.

We are running a test 300BLK 8" Barrel right now that functions flawlessly subsonic. It sports one of our set screw mounted gas blocks and we have had no problems. We manufacture them to allow a snug press fit, so that is one of the key factors in its success. The only difference between the taper pin and set screw models is that the taper pin has no ability to rotate, that is why we have also drilled ours to be taper pinned if the user wishes.

The pure geometry of the circle can make any gas block suck. The clamp style is prone to many problems if the hole is not reamed to exactly .75. Squeezing the bottom on an out of spec hole will distort the top and cause gas leaks (take any pliable cyclindrical object and squeeze the bottom and see what happens at the top!). At least with a set screw mount if the barrel or gas block is out of spec you are forcing the top against the gas hole where it should be. Dimples in the barrel will eliminate rotation almost as well as a pin unless you hit it with a sledge!

Regardless of the type of mount, all gas blocks are prone to failure. It's all in the manufacturing process in my opinion.
 
thats allot of reading for a simple question but allen gun works makes the most sence. i think quality of the item has to be the starting point.
 
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