Chumly from United States, MI Public Profile

I purchased the AR-15 version of this tool because it provides alignment support to the upper receiver and barrel during maintenance. This tool relieves the barrel locating pin to upper receiver alignment notch from taking the rotational force generated as the barrel nut or muzzle device is tightened or loosened. It also can be used as a gauge to see if a previously assembled upper receiver and barrel are properly aligned. Some have complained that the tool won't slide into the upper receiver and into the barrel extension, this is most likely an indication of an alignment issue and not a fault in the tool. I have used this tool with two 1980's vintage Colt A2 uppers. One upper was the dual push pin style while the other was the Sporter version with the double screw head. The tool worked properly with both of those uppers with no problem. One barrel was a Colt while the other was a Bushmaster and again no problem. FYI, I also tried this AR-15 sized tool in my Rugar SFAR in 7.62 NATO and it fits that rifle as well. While certainly costly for only occasional use by a hobbyist, this is a well made and finished professional grade tool that can prevent damage that is more costly than it's price.

I purchased this co-witness mount for use on a Colt carbine with a standard height front sight and an EOTech 512 holographic sight. With the A2 rear sights and non-F front sight base I was not able to get a co-witness view of both front and rear iron sights through the EOTech sight. I was left with the rear sight obstructing the view through the bottom third of the EOTech while any view of the front sight was below the EOTech sight window and blocked. I ordered a Picatinny rail 0.5" QD riser and that got the EOTech up where I had an unobstructed view through it. The PRI base itself attaches with a knurled head steel bolt that passes through the hole in the top of the carry handle and screws into the aluminum PRI mount. The bolt head has a plastic surface on the face that bears against the underside of the carry handle to prevent gouging and scratching of the carry handle. Positioning the mount in the carry handle and starting the bolt threads is more difficult than it need be and this attachment method and hardware is the area that could be better. You start by aligning the threaded hole in the mount with the hole in the top of the carry handle. There is no physical stop to assist you in doing this by feel, you either have to fumble around trying to start the bolt into the mount with the mount slightly separated from the carry handle or get a view of the holes by looking at the underside of the carry handle to align them. Having more than two hands is also helpful her

This mount seems well made, nicely machined and the package says it fits Picatinny and Weaver style rings. While a Weaver ring does fit, it seems as if the mount is wide and the ring clamp plate is only gripping about half of the dovetail. Burris Zee series Weaver rings will not fit on this base at all. The base is too wide or the the ring is too narrow you can take your pick as to who is at fault but they don't work together so save yourself some trouble and avoid this combination of mount and ring.