Can a $5 piece of red bubblegum cure a fifty-year-old design flaw?

by Joe Carlos

I have mentioned many times in the pages of this magazine that when Stoner designed the AR platform he probably never envisioned it becoming a target gun. There were design elements that made it reliable on the battlefield and easy to work on, but not as accurate as some of the demands put on it today. One of the most glaring accuracy detractors is the method of attaching the barrel to the upper receiver. I offered some simple solutions to curing the problem in “The Relationship Of Barrel Extension Diameter To Accuracy In The AR-15” in the March and April 2013 issues.

The other big accuracy design shortfall is the method of attaching the upper receiver to the lower employing only two loose fitting captive pins. Custom pistolsmiths spend time getting the slide-to-frame fit of 1911 semi autos just right. Precision rifle builders glass bed actions. Yet, a fair number of AR-15 builders overlook all the play between the receivers of the guns they build despite the fact that tightening the receiver fit of the AR takes less time than properly lapping a slide.

Here is an overview of the best methods for tightening up AR-15s and obtaining match-grade accuracy.

Read more in the April 2017 issue.

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