AR Scope Mount Systems
Dr. John Woods 04.06.16
Crucial to an accurate pinpoint shooting AR is the scope mount. You have spent major bucks on a good AR rifle set up and then you stretched the budget for a quality optical scope to set the rig up just right. Now is not the time to go cheap on the scope mount.
AR rifle platforms by their very nature are the most accessorizable (is that a word?) weapons systems ever designed. If yours has a Picatinny rail on the top, then you have virtually unlimited options for adding sight systems to the rifle. The options are also many for putting a high quality, secure scope mount on the rail.
Options for scope mounting on an AR are basically of two types. These are single mount fixtures or double mounts. Obviously the single mount is a one-piece mount of either aluminum or steel. Take your choice here, picking weight issues over the inherent strength of steel.
I tend to lean slightly toward steel mounts as I have had less problems with them. Steel can and does rust, of course, if you do not maintain it. Aluminum does not rust, but it does scratch and mar easily. I have also had some issues with screws turning out in aluminum tapped threads. I prefer steel mounts with the blue screw lock glue on the threads.
One-piece mounts tend to be tricky in terms of scope heights and setting forward eye relief. The best part about a Picatinny system is that scope mounts can be moved back and forth in the rail grooves to adjust. You may find with some scopes that an extended mount works best. The single one-piece AR mounts by Nikon are already set up this way. They must know the issues. Other high quality 1-piece mounts are made by GG&G in Arizona. These come in bolt on or with adjustable quick-release levers.
There are many brands of two-piece scope mounts that fit the Picatinny rails. Some of the ones I have used with good success are GG&G, Leupold, and Midwest Industries. These also come in cross bolt configurations with heavy nuts to tighten with a socket and socket wrench, but use care in the torque you apply. I have never twisted one off, but it could be done.