Let me start by saying this one was on me I knew better, I have a Stag Arms AR-15 and getting it to where I want it payday to payday. Well it's a flat-top and Im a firm believer that any electronic sight can screw up and with my luck it would be when SHTF. I started looking at diff iron sights for back up and they run between $120.00 up to $280.00 a set. I was in a local gun store and found a pair that seemed to be a good heavy made sight they are GM-FRS1 put out by Global Military Gear (Mil Spec) for $60.00 bucks so I picked them up and put them on my AR. Front sight went on good back sight started out a little tight then after a few stiff turns it freed up and tightened down on the rifle good and tight. Upon getting the sights on I inspected both front and back sight, front sight perfect back sight was cracked at the base. The gun shop told me they couldn't replace it contact the company. I did so talked to a guy in NY who said that was a first just E-mail him my address and he would put a new sight in the mail the following morning. I told him I would send the back sight back to him as soon as I got the new one. Two weeks passed no sight so I sent a second E-mail told the guy if he changed his mind about replacing the sight E-mail the part number and I would order and pay for just the rear sight. Week three still no contact I talked to a couple other guy's at the gun store had the same problem with the sight system and got the same top notch service I did. So if you are looking for AR parts avoid this company and remember you pay for what you get.
I hate technology. And it seems to me like having a battery powered battle rifle is about as dumb as a guy can get. With that said . . . I bought an Eotech and put it on my AR because it IS fast Anyway my point is mounting a battery powered optic on my AR means (to me anyway) that I MUST HAVE backup sights. These were cheap and I figured I'd destroy them, so cheap was good. MBUS® - Magpul® Back-Up Sights 'couple of years later I have beat the crap out of these plastic sights and they still work just fine, and have never needed re zeroing.
You should give these a try if you have a rail up front. You turn the drum out to 400yds but also accurate up close with the "v" notch. I also have an HK91 and find having the same sights on both guns comforting. If you have some type of optic and you want to co-witness, you'll have to check out the mount height. 416 Front Rear Sight Picatinny for HK 416, HK 417, MMR416, MMR417, P416, AR15, AR10, RTG Gun Parts
Well for sure don't put any plastic (polymer) sights on that gas block rail. I've seen that not work out for several . . . slow thinking shooters, in carbine classes. . . .I know; you are smart enough to know better than to do that. But you saying that makes me remember the looks on the faces of the guys who didn't think it through far enough and found their front sights "wilted". Classic "WTF!?!?!"
Those aren't the actual sights I have, but the cheapest I could find. I think mine are made by LaRue or Troy Ind. The front sight folds away but the back is set. Centurion also makes a set but they're pricey. Here's what the co-witnessing should look like. You can't really see it, but the red-dot will be exactly on the front sight pin.
