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Posted: 5/17/2014 3:19:20 AM EDT
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Hello, still working on building my first AR. Stumbled upon this as I was trying to pick out a gas block.
It says you can adjust the amount of gas that travels through the tube. I understand that having not enough gas will lead to failing to complete cycle. But if you have too much gas what can happen? Just unneeded wear on your BCG and it gets dirty faster? Here is the link to the Seekins Precision Adjustable Gas Block Any help will be appreciated! Going to finish my upper next Friday! |
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Adjustable gas blocks allow you to reduce the amount of gas and are generally helpful when you make a modification where less gass will help the gun run more reliably. There are some like the Noveske Switch Block that have two settings, one for regular shooting and one for suppresed. There are also adjustables that let you tune the gas from full on to totally off (which effectively gives you a single shot AR). These can be very usefull to reduce the gas to tune the gun when using a low mass BCG and buffer. 3 gunners use these alot.
I only have LMT and BCM barrels and the gas ports seem to be the correct size so they run fine (which is said to be true of the best manufacturers). Apparently some brands drill them a little larger so they function with cheaper ammo. There are others in addition to what you listed. SLR and Syrac come to mind, and there are others as well. I just bought an SLR for my build, but I am using it with a JP low mass BCG. |
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You can tune the gas so the AR gets just enough gas to cycle (and lock back after the last round in a magazine) with a particular load. That prevents the buffer from striking (or minimized the force with which the buffer strikes) the buffer tube/receiver extension. The result is less perceived recoil and less movement of the AR and its sights or optic relative to the target in operation, which is useful in competition. The AR shoots smoother, flatter and softer. It's not recommended for combat because it also minimizes the excess "power reserve" that may be needed to operate the AR If it is dirty or with lower pressure ammunition.
See http://www.jprifles.com/1.4.7_bc.php for JP Rifles' claims with respect to their system. |
| I have the syrac gen 2 with a wmd nib bcg, standard weight carbine buffer/spring, and a yhm muzzle brake. It's tuned to shoot steel reliably as well as brass. I tuned it with the rifle dry and 500 rounds dirty for reliability. Shoots much smoother and flatter than before. Id say get the block only if you can be effective with out it. That way if you do get it, you are much better at shooting. Also, the first answer to overgassing is moving up buffer weights. |
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I just put THIS GAS BLOCK on a pistol build.
I wanted to be able to control the gas to ensure it was field reliable, it being a pistol and all. Install was cake with a dimpled barrel to help align it. It functioned 100%, beginning by throwing brass at my 4 to 5 o'clock. After intial rounds, was ejecting at 3 to 4 o'clock. One surprise, the gas adjustment set screw isn't in front. It faces back at the shooter. You'll probably have to remove your handguard to adjust the gas. If it was a 14.5" or longer barrel, I wouldn't have used it. |
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