RMR on ACOG Mounting Options (00:00)
If you want to add a close-range or backup red dot to your rifle that has an ACOG equipped, you have a couple options. You can do an offset red dot on, you know, either side of the gun, whether you're righty or a lefty and run a mini red dot that way. Or you can use a piggyback option using the two mounting locations on the two different types of ACOG out there to put a RMR or other similar miniature red dot up above the optic. So by raising your head, there you go. You have a high-rise optic.
Fiber Optic vs. LED ACOG Models (00:29)
So what we have here is the traditional TA31 ACOG that will mount an RMR or other mini red dot in the back. And then we also have the TA02. And the primary difference to this particular ACOG is it actually mounts the RMR—or other mini red dot—actually at the front of the optic. Now I much prefer this. It's not quite as traditional as the TA31 style. And what we're gonna do is we're gonna talk about both and we're gonna show the install process for the RM35. The RM35 model, and it's kind of confusing, but the RM35 is the one that goes on the TA31. And the RM66 is the one that will go on the battery-powered TA02, and they are not cross-compatible. So make sure you pick the right one for the right ACOG that you have.
Installing the RM35 Rear Mount (01:11)
The RM35 comes with all the necessary screws to mount the plate to the optic and the RMR to the plate itself. But the first thing we're gonna do is we're gonna have to remove two screws that they include on the ACOG that protect the threads in the rear. Now that we have those screws removed we can take the plate—it already has the two screws, the primary mounting screws already indexed—we'll just line those up. And for these, we're just going to do hand tight and a little bit. It stops in there though. You really can't over-torque it.
And then what's included are two little… Basically, these are tiny little screws that are going to punch through in the top of the plate itself. And they're going to rest—gently, I might add—on the main body of the ACOG. This prevents the entire thing from tilting forward, either as it's being bumped through trauma, blunt trauma, I should say. So we're going to go ahead and index these. We're gonna hand tight them to get 'em started. Now it's important that when you're tightening these down, you stop right when it touches the optic body. If you keep going, it's actually going to lift the entire plate up and that's gonna cause elevation issues with the RMR when it comes to zeroing. So we don't wanna do that. Plus it causes strain to the bolts in the back. So we just wanna make sure it touches and does not actually screw into the body. Touches. And touches. And those shouldn't move. They have loctite. So those are good to go. So now this is a very stable base to now accept the RMR or other type of red dot.
So we're gonna unscrew the screws that it comes with for the optic. We're then going to take our RMR. Place it on top on the front bosses. And these are already loctited. So we don't have to worry about that. We're gonna do hand tight plus a little bit. And there you go. You've got the ACOG with the RMR mounted to the rear, all traditional like, and now it's ready to mount to the rifle.
To demonstrate how high the RMR is sitting. It is up there. You know, the height over bore is definitely something you're gonna have to train and get used to. But it is still a very viable setup at close range. And with training you'll know exactly what you need to do with it. And you'll be good to go.
Zeroing the RMR (04:16)
As far as zeroing the RMR or the optic that you put on top of the gun, you could match the zero distance to the ACOG, which is probably a 100 meter, or 100 yard zero, which I do recommend, especially on a gun like this. This is a 16" Colt. So for the BDC to all line up, that's what the ACOG was originally intended for. But what I've done is I'll just do a 50 / 200 meter zero. I'm probably not taking the RMR out past a hundred realistically.
And what I do is I take our rifle zero target, and I literally just shoot for… I can do my standard 50 / 200 offset, and then I can confirm with 50, or I can just go straight to confirming with the big box itself. Or if I decide to do a 100, because I do want it to match the ACOG—just so everything's the same and it's not confusing—I'll just end up shooting either box at a hundred and walking everything in, using the grid of the target. And I will be good to go.
Which Setup is Best? (05:04)
Now, as far as which set up to choose, you know, which ACOG, which RMR position, you know, in the rear or the front, there's a lot of advantages to the TA02 that puts the RMR up front for gas mask use and also for night vision, especially for night vision use. And also seeing just more around the optic, versus the entire basically being in your eyeball. But if you're, you know, maybe a GWAT vet, and this is what you use, this exact rifle right here. And this is what you want to go with, obviously, you know, you might want to do that. Or if you already have a TA31, or you picked up a super salty one on eBay or something, an old government issue one, and it's only going to accept the RMR in the rear well then, that's kind of the only option you have to go, you know, forward with.
I recommend the TA02 setup, if you do wanna run an RMR on top, I think it has a lot more advantages compared to the fiber optic model with the RMR in the rear. But that's gonna come down to your decision and your preference, what you want to choose.
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