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How important is AR-15 Upper/Lower Receiver fit? Is the Accuwedge of any benefit?

by Clint McKee

AccuWedge Installation

Part I:

There have been a number of questions lately about looseness of AR-15 upper/lower receiver fit, Accuwedge, etc. Here's my response:

First of all, does looseness or tightness of fit make a difference in accuracy? Maybe, maybe not (how's that for sage advice!). Some say yes, some say it does not matter. In some rifles, it may make a difference, in others, we do know they still shoot well, even though the receivers "flop around."

Personally, I find a rattle trap very annoying, whether it be a rifle, pistol, car, etc. So, at least we do know that the Accuwedge does not hurt accuracy, and eliminates the rattle trap syndrome!

Second, it seems to me that since the sights are on the upper receiver, and you hold the rifle primarily by the lower receiver (pistol grip), that if the upper moves relative to the lower, then the sight picture can move, relative to the hold!

Thirdly, all the engineers & physicists on this group know that when things can move freely, they will, when subjected to a force. If the upper & lower receivers are dancing all over town each & every time the recoil energy is transferred, then is it not unreasonable to assume that the upper & lower receiver take down pin holes are getting an unreasonable amount of wear from being shocked up & down, back & forth, left & right? The pins are steel & the receivers are aluminum. Guess who loses the battle over time?

Now, it is true that we sell the Accuwedge for the Princely sum of $4.95, and, so yes, we are tainted by the rather substantial profits we will record should you purchase one of these from us (BTW, some sell it for less!) However, for about 5 bucks, I would not build, ship or shoot one without it. Why would anyone?

Part II:

What we have here is a matter of magnitude.

At worst, loose fitting upper/lower receives can cause malfunction, though this is rare, in the scheme of things. What is often lost in this debate is that all U.S.G.I. M16's have loose

upper & lower receivers. It's the way they were made! And for good reason. But that's another story, and the M16 is a machinegun.

At best, loose fitting upper/lower receivers have no impact on functiuon, nor even accuracy! Inherent accuracy that is.

Try shooting for points when the upper is moving (held in one hand) relative to the lower (held in the other hand). Your sight picture & hold will most certainly suffer, and thusly, your "accuracy" will be diminished. You are at a severe disadvantage, all other things being equal.

The accuwedge should be installed on every AR15 (Colt installs them routinely with every factory rifle), unless, one uses the JP rear tensioning pin, which is the best solution, albeit a lot more expensive.

In addition to the "accuracy" question, there is another area often missed.

The accuwedge "buffers" the violent, though momentary, shock to the front & rear takedown pins. When things can get a running start, as you get with loose fitting parts in motion, inertial energy will exacerbate and even accelerate the wear to any parts it is subjected to.

So, at the least, get a $4.95 Accuwedge, OK?

--Clint McKee

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