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Posted: 9/30/2011 9:41:11 PM EST
I've come across different gas block mounting solutions (set screw, clamp screw, pinned, etc) and I was wondering what sets each one apart from the other. What are your thoughts on each type? What are their advantages/disadvantages?

Thanks
Link Posted: 10/1/2011 1:40:23 AM EST
Set screw: Mounts to the barrel with one, sometimes two, screws. Needs the barrel to be dimpled so the screw(s) have somewhere to sit. Some barrels come dimpled, some don't. Requires a cheap jig and a electric drill/drill press to do.

Clamp-on: Pretty simple, slide the block on the barrel and clamp it down by turning the two screws.

Pinned: Probably the hardest of the three to do. Two, sometimes one, 'slots' are drilled in the bottom of the barrel and the pins in the gas block line up with the 'slots' to hold it into place. Again, requires a drill press and some basic machining skills.

Strongest to weakest would be pinned, then set screw, then clamp on. But that's debatable. I've heard of someone trying to break a clamp-on loose, but ended up shearing the barrel index pin instead.

Hope this helps.







Link Posted: 10/1/2011 9:16:09 AM EST
Originally Posted By Engel12626:
Set screw: Mounts to the barrel with one, sometimes two, screws. Needs the barrel to be dimpled so the screw(s) have somewhere to sit. Some barrels come dimpled, some don't. Requires a cheap jig and a electric drill/drill press to do.

Clamp-on: Pretty simple, slide the block on the barrel and clamp it down by turning the two screws.

Pinned: Probably the hardest of the three to do. Two, sometimes one, 'slots' are drilled in the bottom of the barrel and the pins in the gas block line up with the 'slots' to hold it into place. Again, requires a drill press and some basic machining skills.

Strongest to weakest would be pinned, then set screw, then clamp on. But that's debatable. I've heard of someone trying to break a clamp-on loose, but ended up shearing the barrel index pin instead.

Hope this helps.


Pinned is a PITA in every way.

Set screw is only strong if the barrel is dimpled. Another cost and PITA.

Clamp On is correct in every way EXCEPT for the smallest of low profiles.

If you don't need the lowest profile then Clamp On {think ARMALITE or Sabreco} is always the correct answer.

Link Posted: 10/2/2011 5:31:48 AM EST
Originally Posted By DaveS:
Originally Posted By Engel12626:
Set screw: Mounts to the barrel with one, sometimes two, screws. Needs the barrel to be dimpled so the screw(s) have somewhere to sit. Some barrels come dimpled, some don't. Requires a cheap jig and a electric drill/drill press to do.

Clamp-on: Pretty simple, slide the block on the barrel and clamp it down by turning the two screws.

Pinned: Probably the hardest of the three to do. Two, sometimes one, 'slots' are drilled in the bottom of the barrel and the pins in the gas block line up with the 'slots' to hold it into place. Again, requires a drill press and some basic machining skills.

Strongest to weakest would be pinned, then set screw, then clamp on. But that's debatable. I've heard of someone trying to break a clamp-on loose, but ended up shearing the barrel index pin instead.

Hope this helps.


Pinned is a PITA in every way.

Set screw is only strong if the barrel is dimpled. Another cost and PITA.

Clamp On is correct in every way EXCEPT for the smallest of low profiles.

If you don't need the lowest profile then Clamp On {think ARMALITE or Sabreco} is always the correct answer.



This. There is a persistent rumor going around the net that clamp ons are not as secure as set screwed blocks. In actual fact, a well fitted and properly installed clamp is stronger as it pulls tight around the entire circumference of the barrel, not just a pointed spots like the set screw types. As mentioned above, set screws without dimples are seriously compromised. In addition, accuracy gurus will always advise a clamp as they say the pointed stresses on the barrel from set screw types can affect fine accuracy. Not overly important in a combat carbine, but why accept such a compromise when for the home installer a clamp block is easier and more efficient. As noted above, set screw types do have a skinnier profile for very use with thin rails, but some clamp low pro's are close - I have a couple of the VLTOR clamps that work with thin rails such as the TRX Extreme.
Link Posted: 10/3/2011 6:35:52 AM EST
Clamp on is under rated and an excellent solution if not pinning a block. Good enough for Noveske's switchblock!


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