The best time to accurize an AR is while building it, but going back and tweaking an existing rifle or carbine isn’t that difficult. Here again, having a few specialized tools makes the job easier. The two tools I use most often are a receiver lapping tool and muzzle crowning/re-crowning tool set. The lapping tool allows you to “true” the front face of the upper receiver, seating the barrel extension squarely and theoretically aligning the bore with the upper receiver. In this case I’ve found that theory follows practice. I have yet to encounter an AR that hasn’t tightened up noticeably after truing the receiver. In a couple cases this procedure changed 2 MOA plinkers into 3/4 MOA shooters. That’s quite dramatic and makes me wonder where the poor tolerances exist: upper receivers, barrel extensions, barrels or some combination. Care is required to prevent damaging the receiver, as the lapping tool must be well lubricated to prevent “burning” of the inside surfaces of the upper receiver. Commercially available lapping tools have a relief groove to prevent lapping compound from getting inside the upper receiver and removing metal from the wrong places.
Re-crowning the muzzle is a procedure I don’t do automatically. If I see a damaged or faulty factory crown I’ll clean it up, usually using an 11 degree cutter. If I have a rifle or carbine that isn’t living up to its potential and I haven’t touched the crown, I re-crown it and that normally provides an improvement. I say “normally” because a perfect crown won’t fix a dog of a barrel, but it can help a situation where the crown is contributing to inaccuracy. Although it’s a relatively simple procedure, I leave crowns of acceptable or above average performance guns alone.
The result of good parts selection, fitting/assembling and final accurization is realized downrange. An Olympic Arms heavy barrel and Geissele Automatics High Speed National Match trigger helped this V/M model group sub 1/2-MOA regularly. Hornady’s 55 gr. V-Max has consistently provided good factory performance in all guns I’ve built. Photo courtesy of Rifleman Consulting LLC.
As I write this, winter’s gray clouds are surpassed by the much darker prospects of life for gun-enthusiasts under the “change” government headed our way. I suspect by the time this article reaches print we’ll have seen the first shots across the bow of our Constitutionally-guaranteed and Supreme Court-affirmed rights to firearms ownership and possession. Perhaps no branch of the gun tree will be more savagely pruned than that of semi-automatic centerfire rifles and carbines. Wrongly categorized as “Assault Weapons”, these firearms have moved firmly into mainstream shooting. With nearly all AR manufacturers and custom shops offering versions suitable for target, competition, home defense and multi-game hunting, it’s clear to any honest shooter that the platform lends itself well to various pursuits. The timing is ironic here: Just when the industry is embracing the AR as another useful tool versus a mere weapon of war, the voting majority of Americans has set the stage for legislating these very capable arms right out of legal ownership. Of course I had no idea we’d be headed in this direction when I picked the AR platform to specialize in after retiring from service. Sour grapes? Yup. Poor timing? Double Yup. Worried about the future of American freedom? Off the Richter scale on that one.
If I’ve learned anything since starting down this road, it’s that selecting proper components, applying attention to detail in fitting/assembling and careful accurizing can yield very good shooting, semi-automatic rifles. I’m not sure what limit exists on AR accuracy, but I have several roads to travel in pursuit of the best practical accuracy I can achieve (i.e. without converting to single-shot, etc). I plan to dig deeper into hand-loading and building a .308 Win AR, assuming parts will ever become available. I’ve also got a set of unused bore-laps currently giving me the same look I get from my Lab when he’s tired of waiting. The fact that I’m already able to achieve 1/2 MOA or better without bedding blocks, ACRA-GLAS® or stocks replacement shows me just how versatile this shooting platform really is, and just how well-suited it is for sporting uses. I can only hope that the folks in Washington DC are honest enough to recognize that. I won’t hold my breath waiting for such candor though….
Midway USA, Inc.
Olympic Arms, Inc.
Steve Adelmann is a former SOF sniper with 21 years and 10 combat tours of duty in the US Army. He owns Rifleman Consulting, helping freedom-loving US citizens through writing, advising and AR-style rifle customization services. Go to: http://www.riflemanconsulting.com for more information.
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