View Full Version : For those grumbling about upper+lower fit...

08-18-2006, 2:38 AM
I ordered an Accu-Wedge from MidwayUSA the other day, and just got around to installing it today. Since I've seen folks stressing on here about upper/lower fit, I thought I'd go ahead and post my experience with the accu-wedge. My gripless AR had a slightly irritating amount of play to it, so I decided to see what $3 worth of plastic can do.

This article's permanently located at http://www.thegunwiki.com/Gunwiki/ProcInstallAccuWedge - but I figured that I'd go ahead and post it here as well.

Installing an Accu-Wedge

Ever since I got into the AR-15 scene, I've seen a LOT of people expressing great concern about wanting their upper and lower receivers to fit together as tightly as possible. While some folks take this to the extreme of buying upper receivers until they find one that will fit tightly with their lower, I find that it's not THAT critical. However, it's a bit annoying to have a rifle where the upper and lower shift noticeably.

Enter the Accu-Wedge. I'm not sure whether it's rubber or some kind of polymer, but it's a spongy bit of red stuff that goes into the spot directly beneath the rear takedown pin on your AR. You insert the accu-wedge into the slot, then put the upper down on top of it, then put the whole thing together. I've installed it on one of my rifles with a very loose fit, and it went from very loose to only shifting a little.

The big thing which convinced me to give it a try was the price. From Midway, with a C&R discount, it's only $3ish. Nothing else that cheap will make as big an improvement in your rifle's ergonomics.

I will say, though that there are many people who should NOT invest in the Accu-Wedge. Namely, my fellow Californians who use pinned-magazine rifles. Of necessity, the accu-wedge makes the fit between the upper and lower receivers much tighter. This would translate to extra stress on the takedown pin when you're flipping the top open to load it. However, in a gripless, detachable-magazine configuration like mine, there's no reason not to use an Accu-Wedge to tighten up your rifle a little.

On the other extreme, we have people who want the utmost in tight fits on their receiver. For them, the best solution is the fancy tension pin solution from JP Precision. Their system fits into the takedown pin hole, then you use a tool to screw it in place - at which point it sort of mushrooms in the hole. You won't be removing it without an allen wrench, that's for sure.

Considering that the accu-wedge comes with no installation instructions, I felt like doing my own tutorial on what it does and where it fits. While I imagine that most folks who order one will figure it out in short order, I think these pics will help folks understand why they might want one on their rifle.

My M-16-oid

The Accu-Wedge itself

About to install the Accu-Wedge

Inserting it into the receiver

08-18-2006, 2:40 AM
Wedge in place

Wedge installed and ready to go

Closing it back up

08-18-2006, 5:34 AM
The only bad thing about the acuwedge is it is not a very good idea for FAB-10s or fixed mag rifles. I bet it works great for guns you don't plan on pulling the rear pin on 10 times in a range session.

08-18-2006, 7:03 AM
I use it and like the fit very much. One problem though, it doesn't fit Lauers. I don't know about other brands as well.

A good way to remove the rear pin with the Wedge installed is to squeeze the upper and lower together with your hand through the handle opening and your thumb on the top of the underside trigger well. The pin can be quite hard to remove as the wedge puts a nice bit of tension between the recievers.

Also, for those worrying about function problems, I have had zero. When you look at the buffer, you should see a ring where the carrier has worked down the finish. You should see a nice ring centered on the buffers face. There should be some clearance between the ring and the edge of the buffer. That shows you that the carrier hits the buffer nice and centered.