Of all the AR15 platform modifications available, Adjustable Rifle Gas Blocks are among the most pivotal AR-15 / M4 Accessories you can buy when it comes to performance enhancement. A firm AR gas block will all but eliminate your gun's recoil, making for a seamless recoil recovery and a quicker target acquisition in follow-up shots. It will also prevent the bolt from overheating, rendering your cool-down period unnecessary. In the name of reliability, most AR manufacturers err on the side of over-gassing the operating system of the upper receiver, making the stock AR a bit of a beater rifle with a snappy recoil. The AR Adjustable Gas Block's purpose is to fine-tune the gas pressure on the standard, over-gassed direct impingement AR15 systems, which is done by sealing the gap between the gas tube and the gas port.image