ENCLOSED EMITTER+RMR FOOTPRINT

[314159]

I have not one but two shotgun mounts that fit the RMR footprint. Preferring to use an enclosed emitter style sight for a long gun what are my options?

Bonus points if the sight does not require some sort of intermediate adapter plate to make it work out. the lowest possible solution would be best here.

Thanks for any ideas...

[WobblyPossum]

Trijicon just released the RCR. It’s more expensive than the RMR but uses the same footprint and mounts with capstan screws.

[HCM]

I have not one but two shotgun mounts that fit the RMR footprint. Preferring to use an enclosed emitter style sight for a long gun what are my options?

Bonus points if the sight does not require some sort of intermediate adapter plate to make it work out. the lowest possible solution would be best here.

Thanks for any ideas...

As noted the new Trijicon fits the bill but I have concerns about the capstan screws used for mounting, especially under shotgun recoil.

Other options such as the ACRO and Holosun EPS /509 require an adapter plate.

[314159]

That saved me research which might have gone down some rabbit holes. Thanks.

[Lon]

That saved me research which might have gone down some rabbit holes. Thanks.

The new Trijicon is the only game in town that doesn’t require an adapter plate.

[1911Nut]

Can anyone explain the perceived advantage of a capstan screw to mount an optic on a weapon?

[1Rangemaster]

Can anyone explain the perceived advantage of a capstan screw to mount an optic on a weapon?

Not sure there are a lot advantages, except that this allows the unit to be direct mounted on an RMR cut slide. Given that the RMR cut was one of the first years ago, that means no retrofitting a plate or another slide/cut.
The system does not have a lot of exposure, and it remains to be seen if the screws can be torqued appropriately. Time will tell.

[HCM]

Can anyone explain the perceived advantage of a capstan screw to mount an optic on a weapon?

There isn’t one other than indulging Trijicon’s vanity.

It lets let you turn a screw from the side when top access is impossible. Such as a closed emitter optic using on open emitter footprint.,

Which is great until everything doesn’t work perfectly. good luck dealing with stuck broken or miss threaded capstan screws.

[JCN]

Which is great until everything doesn’t work perfectly. good luck dealing with stuck broken or miss threaded capstan screws.

Theoretically it should still be reasonable unless BOTH capstan screws fail at the same time.

The sliding notch on the unit means that if one side still works, the other side can slide the optic off even if broken or nonfunctional. Theoretically.

Also, if the cap broke off, then it would be even simpler to remove the optic.

If there were a partial cap compromise (unlikely failure mechanism) could use a washer in a collar to clamp a drill bit from walking and sliding and drill out the cap similar to how you would drill out the head of a traditional screw.

[Magsz]

As noted the new Trijicon fits the bill but I have concerns about the capstan screws used for mounting, especially under shotgun recoil.

Other options such as the ACRO and Holosun EPS /509 require an adapter plate.

Shouldn't the recoil bosses/lugs be taking the brunt of the recoil energy?

[HCM]

Shouldn't the recoil bosses/lugs be taking the brunt of the recoil energy?

On pistols, I’m more concerned with installation / removal issues, cross threading etc than shearing under recoil.

Shotguns tend to be harder on….everything.

[Magsz]

On pistols, I’m more concerned with installation / removal issues, cross threading etc than shearing under recoil.

Shotguns tend to be harder on….everything.

I hear ya. Having said that though, if there are recoil bosses, shouldn't we be ok? RMR's are holding up on CROM mounts on the 1301's just fine it seems.

[HCM]

I hear ya. Having said that though, if there are recoil bosses, shouldn't we be ok? RMR's are holding up on CROM mounts on the 1301's just fine it seems.

How many broken, cross threaded, stuck, broken etc optics screws have you seen ? Not to mention the wonky Torque procedure.

The more I think about capstan screws the less ai want to deal with them on anything.

[Magsz]

How many broken, cross threaded, stuck, broken etc optics screws have you seen ? Not to mention the wonky Torque procedure.

The more I think about capstan screws the less ai want to deal with them on anything.

I'm not an armorer so I don't have that data.

I've been running optics full time since 2016. I have never personally broken or stripped a screw. I have however seen a handful of issues and read about a zillion more so yeah, it's an issue.

I'm still confused as to why you're worried about recoil on a shotgun for this optic? Once again, shouldn't the recoil bosses mitigate this? I would imagine that a Capstan screw is probably harder to strip than a torx/allen? Do you disagree? You seem REALLY leery of this optic and i'm wondering why? I'm not really familiar with Capstan screws.

[Hambo]

. If there were a partial cap compromise (unlikely failure mechanism) could use a washer in a collar to clamp a drill bit from walking and sliding and drill out the cap similar to how you would drill out the head of a traditional screw.

If you're saying that you can drill the cap from the side, that's going to be far more difficult than drilling the head of a traditional screw. There's not a lot of room, and I think it would take a good setup in a milling machine to not hit the optic. I agree that it's unlikely to happen, but there's always an idiot who can fuck up anything that has been engineered.

[JCN]

If you're saying that you can drill the cap from the side, that's going to be far more difficult than drilling the head of a traditional screw. There's not a lot of room, and I think it would take a good setup in a milling machine to not hit the optic. I agree that it's unlikely to happen, but there's always an idiot who can fuck up anything that has been engineered.

IMO it wouldn’t be bad.

I have this jig but you could make something similar pretty easily.

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Spring loaded punch the cap head and clamp jig to slide wearing optic.

Dremel or drill press with carbide tip.

I’ve done similar things when I was drilling ports in a barrel while it was still in the slide, through the slide cut windows.

[WDR]

Doesn't the RCR require milling the recoil bosses flat (IE: removing them completely) to mount to the RMR footprint?

[WobblyPossum]

Not that I’ve heard.

[Hambo]

IMO it wouldn’t be bad.


I thought we're talking about accessing the screw here:

110178

Then drilling/milling the head through that opening.

[JCN]

I thought we're talking about accessing the screw here:

110178

Then drilling/milling the head through that opening.

We are.

So think of the following.

1. If there’s a fracture or screw failure, the cap head is going to be loose and just slide out with the tip still stuck in the slide. Then it’ll be no different than any other optic removal and screw extraction with vampliers.

2. The mounting of these is you hand thread one screw with the optic off and the slide the body on. You won’t cross thread both sides. If you cross thread one side, the optic won’t tighten down because it won’t be flush angled and you can cut or saw it from below. But you won’t be able to get to that point realistically.

So basically you won’t get to either of those failure points that makes extraction worse than a traditional optic.

BUT…. let’s say for the sake of discussion you did fuck up royally and you need to extract the screw.

I don’t think it would be a big deal.

Spring loaded punch to dimple here in green and then jig or drill press with a 2mm carbide bit.

110180

[JCN]

Also will point out that if you hand thread the first side and slide the optic on… it’ll hold the other side screw in alignment so cross threading will be very, very unlikely.

There’s not much space in the optic body for the cap head to tilt and cross thread if the other side is already partially seated. It would function as a guide to help alignment.

[HCM]

I'm not an armorer so I don't have that data.

I've been running optics full time since 2016. I have never personally broken or stripped a screw. I have however seen a handful of issues and read about a zillion more so yeah, it's an issue.

I'm still confused as to why you're worried about recoil on a shotgun for this optic? Once again, shouldn't the recoil bosses mitigate this? I would imagine that a Capstan screw is probably harder to strip than a torx/allen? Do you disagree? You seem REALLY leery of this optic and i'm wondering why? I'm not really familiar with Capstan screws.

I’m leery of this optic’s mounting system in general based on past experience with screw issues.

I’ve also spent some time using a Steiner MPS and find the the thick top resulting from the top mounted emitter less than optimal visually but that’s a separate issue. I think that might be less of an issue on a long gun.

[Hambo]

We are.

So think of the following.

1. If there’s a fracture or screw failure, the cap head is going to be loose and just slide out with the tip still stuck in the slide. Then it’ll be no different than any other optic removal and screw extraction with vampliers.

2. The mounting of these is you hand thread one screw with the optic off and the slide the body on. You won’t cross thread both sides. If you cross thread one side, the optic won’t tighten down because it won’t be flush angled and you can cut or saw it from below. But you won’t be able to get to that point realistically.

So basically you won’t get to either of those failure points that makes extraction worse than a traditional optic.

BUT…. let’s say for the sake of discussion you did fuck up royally and you need to extract the screw.

I don’t think it would be a big deal.

Spring loaded punch to dimple here in green and then jig or drill press with a 2mm carbide bit.


Gotcha. I was thinking of an end mill centered in the opening, which would put it over the junction of the head and threads.

Either way, someone would really have to put the pieces of the puzzle together wrong to need such a solution.