Gas Block Install
- Thread starter RBoom
- Start date
doggin coyotes
Well-known member
I don't feel it's necessary. A good quality set screw will sorta, kinda *dimple* the barrel if you get it good and tight anyway. Should never move.
dtech
New member
I always dimple the barrel for both set-screws. 1) It makes it easy to perfectly align the gas-block, in the shop, and in the field. 2) It keeps the gas-block from moving forward while shooting.
Aluminum gas-blocks expand quickly as the hot gases go through them. When they get hot, they expand and are not as tight as they were when they were cold. There are two constant forces on the gas-blocks that make them want to move forward: 1) Recoil. When the rifle is fired, it moves back, and the gas-block wants to stay where it is, so it tends to move forward with respect to the rest of the rifle.
2) The gas-block has the gas-tube feeding the carrier-key and carrier with gas. This force is what is opening and moving the heavy carrier back into the stock. That force has an equal and opposing force that wants to push the gas-block forward.
If you don't want to make dimples in your barrel, then at least get the gas-block positioned correctly, then heat the gas-block with a hot-air gun or propane torch. After heating it, torque the set-screws down a little more. This will ensure that when the gas-block gets heated by the hot gases, it will still be tight.
In "the old days" I have seen gas-blocks move forward because of the two reasons I covered earlier. If the block moves forward fairly quickly, the port in the block will eclipse the gas-port in the barrel to the point where the rifle will begin to short-stroke. If the block is fairly tight, and moves forward quite slowly, then the hot gases can actually erode the aluminum around the gas-port in the gas-block. The block will continue to move, slowly cutting a path through the aluminum so the rifle continues to operate. I have seen both happen, but never with dimpled barrels.
Aluminum gas-blocks expand quickly as the hot gases go through them. When they get hot, they expand and are not as tight as they were when they were cold. There are two constant forces on the gas-blocks that make them want to move forward: 1) Recoil. When the rifle is fired, it moves back, and the gas-block wants to stay where it is, so it tends to move forward with respect to the rest of the rifle.
2) The gas-block has the gas-tube feeding the carrier-key and carrier with gas. This force is what is opening and moving the heavy carrier back into the stock. That force has an equal and opposing force that wants to push the gas-block forward.
If you don't want to make dimples in your barrel, then at least get the gas-block positioned correctly, then heat the gas-block with a hot-air gun or propane torch. After heating it, torque the set-screws down a little more. This will ensure that when the gas-block gets heated by the hot gases, it will still be tight.
In "the old days" I have seen gas-blocks move forward because of the two reasons I covered earlier. If the block moves forward fairly quickly, the port in the block will eclipse the gas-port in the barrel to the point where the rifle will begin to short-stroke. If the block is fairly tight, and moves forward quite slowly, then the hot gases can actually erode the aluminum around the gas-port in the gas-block. The block will continue to move, slowly cutting a path through the aluminum so the rifle continues to operate. I have seen both happen, but never with dimpled barrels.