Ar15 Scope Mounts

Product Review: GDI ACOG R-COM E-Model Combat Optic Mount

In 1998, I bought my first Trijicon ACOG scope — a TA-11 with the “deadly donut” red circle reticle. My TA-11 served me very well on and off duty on my AR-15. Over the years I have used this scope through all the evolutions of my personal and issued patrol rifles — from fixed carry handles to flat tops. The same year I bought my ACOG, I purchased an A.R.M.S. #19 throw lever mount for it. At the time this was the best mount I could find that would allow me to quickly remove my ACOG and reattach it to the rifle and still maintain zero. My #19 has worked wonderfully for me over all these years.

During some recent testing I discovered that my #19 mount was not holding as tightly as I needed it to on some manufacturer’s rails. It holds solid on A.R.M.S. manufactured rails and most other brands, but on some it is too loose. This is most likely due to variations in manufacturing and tolerances between all the different companies now in the market as compared to the past. In any event, the issue remained the same: I needed a new mount for my TA-11 if I was going to be able to use it on as wide a variety of weapons as possible and that mount needed to be adjustable.

As I began my hunt for a new mount to deal with this issue, I found a product in the 2011 Tactical Assault Gear (TAG) catalog. It was an ACOG mount made by Global Defense Initiatives (GDI) called the R-COM. I looked up GDI’s web page and read up on the company and the R-COM. I learned that GDI was founded in 2002 and is a veteran owned small business out of Temecula, California. Originally, GDI provided security services and specialized training but they have grown to focus on the manufacturing of mounts for optics, lasers and other devices. The R-COM comes in two variations, the B and the E models. The B-model raises the height of the ACOG and allows the mount to extend over the top of a back up iron sight such as the Troy Industries  BattleSight.

This allows more flexibility for eye relief when setting up the scope on the rifle. The Trijicon TA-31 ACOG has a shorter eye relief versus the TA-11 and other models. The R-COM B-Model would be my choice with short eye relief versions of the ACOG. The E-Model places the ACOG lower on the rifle, but when used with a backup iron sight the entire body of the mount must be placed in front of the backup sight. This places the ACOG further forward and reduces flexibility when it comes to eye relief. The TA-11 has a long eye relief so I opted for the E-Model to get the scope closer to the bore.

Using AR 15 Scope Mounts Probably Genius

Because AR 15 rifles do not come with a way to attach a scope, you will need to buy separate AR 15 scope mounts in order to attach a scope. An Ar 15 scope mount attaches to the carry handle. Most AR 15 scope mounts are a rail like those that come on most machine guns.

When you buy an AR 15 scope mount, you need to make sure that you are getting something that will actually work for you. Some scope mounts for AR 15 rifles have screws that work themselves loose even under normal firing conditions. In fact, nothing more than the rifle’s recoil after shooting can cause the scope mount to come loose. Normally, when you have a screw that works itself loose due to vibration, you can use a lock washer to help the screw stay tight. However, if you add height to the screws by adding a washer, it may end up obscuring your iron sights. A better solution is to use some thread sealer to help the screws stay nice and tight.

Once you have secured your scope mount to your AR 15, you should be able to enjoy as much shooting action as you choose.

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