Gas Tube Alignment

Proper gas tube alignment in the AR-15 leads to improved accuracy with fewer fliers. Here’s how to improve it.
by Joe Carlos

We covered gas tubes from the standpoint of function previously in the “Do You Have Gas?” series (January and February 2014.) In this article we will concentrate on the relationship of gas tube alignment to accuracy.

Why is gas tube alignment so important? When I shot competitively I started with traditional one handed bullseye pistol, then combat pistol, service rifle, and finally combat disciplines that required application of both rifle and pistol. I noted early on that many of the lessons learned in one style of shooting applied to others or could be easily adapted to other disciplines. Later in life, when I migrated from shooting to gun plumbing, the habit of looking at what gunsmiths in other fields were doing just came naturally.

One of the groups that initially caught my eye were the bolt gunners, primarily long range competitors (Palma shooters and 1000 yard matches), bench rest and some military snipers. I watched those shooters spending a lot of money on high end actions that were purported to help ensure the bolt face would be square to the axis of the bore and apply equal pressures to the case head for each shot. I actively wondered if any of that could be applied to gas guns.

Early in my tour as the Armorer for the US Army Reserve Service Rifle Team one of my shooters had an interesting observation made using his chronograph. He had been testing several of his National Match AR-15s and noticed the velocity standard deviation of his rifles tightened up noticeably when he shoved rounds up into the chamber to a uniform distance as opposed to just lying them on top of the magazine follower and allowing the bolt to carry them forward into the chamber during slow fire. He wondered if this could also have a positive effect on accuracy. Given what I had observed of the bolt gunners, I readily agreed to investigate.

Read more in our March 2014 issue. Back issues are available.

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