View Full Version : Polishing a Turd aka: Question about my issued RRA Carbine
operator81
03-21-12, 19:11
I'm issued a RRA Carbine at work. It is a flattop model that has the rear sight attached to a section of picatinny rail that covers the entirety of the flattop receiver. Here's a link to the rear sight/rail thingy (http://rockriverarms.com/index.cfm?fuseaction=category.display&category_id=318). I can't remember what uber fancy tactical sounding name they have assigned to this particular model.
We are allowed to install a non-magnifying optic so long as it is either an Aimpoint or an Eotech. I'm leaning towards an Aimpoint and would prefer to have a lower 1/3 co-witness. Can anyone tell me how this section of picatinny rail attached to the rear sight will effect the height of an optic?
I have seen some lower 1/3 mounts for the Aimpoint Micro's but am worried that with this rear sight set up my optic will ride too high. I guess another option would be to just set the optic up as you normally would for a direct co-witness and deal with the little bit of extra height the rail provides.
Thanks
To attempt to answer your question, I don't know how much the height the RRA sight adds to the rail on the upper receiver, so I don't know what mount height would be correct for the particular optic you choose.
Does department policy allow you to change the rear sight? I'd personally want the flexibility that a standard rear sight (like a Daniel Defense A1.5, Troy rear sight (fixed or folding), LMT, LaRue, or KAC) would offer. That way you're not dependent on your rear sight to determine how your optic co-witnesses with your irons.
Battle*Hound
03-21-12, 19:46
What a drag...Good Luck Though
Check out the Larue combo deals. They have 3 different heights. If you call them Larue can probably tell you exactly which mount will work best for you. It's what they do.
I just got a 2MOA T-1 from them. Perfect, as usual.
H
operator81
03-21-12, 20:38
Steadyup: Dept policy does not allow us to change anything. I can't even add a light...at least not yet.
Halmbarte: didn't think about Larue, I'll have to give them a call.
Failure2Stop
03-21-12, 20:51
I would go with a mount that would normally put the optic at absolute cowitness. The built in riser will bump it a little higher.
I don't know exactly where your irons will be, but they won't be cluttering up your dot and should still be contained within the optic tube.
Those mounts were originally used with absolute cowitness EoTechs to provide a buis and a riser in one unit.
Don't lose sleep over having a RRA.
Good buddy of mine has worked for the Capitol Police as a firearms instructor for a long time, and they were using RRAs (at least as of a couple of years ago). I only know of one that had chamber issues (though their contract specified 5.56 chambers, so it appears that one slid through) with M855.
operator81
03-21-12, 21:02
Thanks for the info F2S, I'll give that a shot. Worst case scenario I try a mount and can exchange it if it doesn't work. Not worried about the RRA as a whole. Mine has been fine thus far, I'm just a tad of a gun snob and the State doesn't think I should be ;).
Try to get your armorer to sign up on here!
You should be happy you are being issued a patrol rifle. The Department I work for is still screwing around with the lawyers to try and get rifles into the hands of the officers. They've been argueing for 3+ years now with no end in sight.
The Dominator mount uses a GI-type A2 rear at the standard height. The mount is optimized for use with Eotechs. Eotechs without the integrated riser are absolute co-witness. As noted on the RRA site, the Dominator raises the Eotech slightly out of absolute cowitness. Another absolute co-witness optic/mount combo could be expected to perform similarly. Whether it would be a true lower-1/3 I don't know.
My first choice in optic would be an Aimpoint T1 or H1. For co-witness, in an LT751 mount.
Unless they've changed, the Dominator mounts held a long rail on with only a couple of screws. I would verify stability. I'm also not keen on stacking mounts in general. If you do, loctite the screws, torque it good, make witness marks, and watch them closely.
Hope that's helpful.
operator81
03-22-12, 11:18
The Dominator mount uses a GI-type A2 rear at the standard height. The mount is optimized for use with Eotechs. Eotechs without the integrated riser are absolute co-witness. As noted on the RRA site, the Dominator raises the Eotech slightly out of absolute cowitness. Another absolute co-witness optic/mount combo could be expected to perform similarly. Whether it would be a true lower-1/3 I don't know.
My first choice in optic would be an Aimpoint T1 or H1. For co-witness, in an LT751 mount.
Unless they've changed, the Dominator mounts held a long rail on with only a couple of screws. I would verify stability. I'm also not keen on stacking mounts in general. If you do, loctite the screws, torque it good, make witness marks, and watch them closely.
Hope that's helpful.
Thanks for the help, and as you said, my mound is held by 2 screws at the rear only. That being the case I'm guessing it'd be better to mount the option closer to rear of the rail.
The FBI's Hostage Rescue Team still uses the Dominator mount with an EOTech, as far as I know. They must find that combination acceptable. RRA says the Dominator was developed specifically at the behest (exactly the word RRA used) of the FBI.
I wouldn't worry about the short clamping area, if I were you. The YHM EOTech riser is the same, as is, I believe, the LaRue riser.
A Google image search for "FBI HRT" will yield pictures of their carbine set-up, if you care to see.
The Larue mount for the Aimpoint C/M/ML 2&3 series places the center of the optic 1.7 inches above the rail. Subtract the height your Rock River rear sight rail is above the upper receiver's rail from 1.7 and that will tell you what height your mount needs to be to the center of the optic.
I too prefer Aimpoints and use C-3 2 moa for duty. I do not plan on submerging my optic in more than 10 feet of water, so I don't need an M or ML series.
ForTehNguyen
03-23-12, 08:00
an alternative is to use a rear flip sight. If you were to get an Aimpoint Micro, Daniel Defense makes a H1/T1 mount that already provides the correct height for a lower 1/3. Sight picture is a lot less cluttered when you have a flip rear sight.
Failure2Stop
03-23-12, 08:56
an alternative is to use a rear flip sight. If you were to get an Aimpoint Micro, Daniel Defense makes a H1/T1 mount that already provides the correct height for a lower 1/3. Sight picture is a lot less cluttered when you have a flip rear sight.
Steadyup: Dept policy does not allow us to change anything. I can't even add a light...at least not yet.
Halmbarte: didn't think about Larue, I'll have to give them a call.
Answers lie within the thread.
Sent from my phone using Tapatalk because my wifi blows.
This just in: Dominator mount raises the rail approximately ~1/4".
Larue has four different heights for the T1 mount, call them and ask them which is a 1/4" shorter than the 1/3 one. Maybe the HK660 would be good?
Either way you can't go wrong with the Larue and a T1. I'm sure Larue will be able to get you set up.
So doing a little more research a HK416 is .27 inches higher. So the Larue HK660 would give you a 1/3rd co witness that is only .02" off. Thats pretty damn good.
operator81
03-26-12, 21:07
Sorry for the late replies, was out of state for the weekend. Thanks for solving that for me, you guys are awesome. I'm about halfway find-wise to an Aimpoint.
I mounted one of the RRA http://rockriverarms.com/index.cfm?f...ategory_id=318. to my Flat top with a fSP and it co-witnessed the red retical on the EOTECH just above the front sight post.
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