EOTech mounting

[sanchezero]

OK, first, I know I should be at AR15.com but you have to have a real email acct and mine is not, so there...

Now.

I'd like to mount an EOTech on my bushy flattop and I understand that it cowitnesses fine from the flattop itself.

That's not what I want tho. I wanna use a swan sleeve or SIRS (if I can justify the expense ) and that'll put it higher.

Lemme know please. Hopefully, I've misinterpreted info somewhere and it mounts fine on the swan/SIR.

Thanks.

 

[sanchezero]

Anyone?

 

[hksw]

Does the Bushy flattop have the regular front sight or is it totally sightless?

For what purpose are you thinking of using the SWAN Sleeve for if you don't want to just use the #40 rear sight?

 

[sanchezero]

It does have the reg'lar front sight.

I'd like a SS cause I plan to mount it pretty far forward; I'll be getting a long one. The only time I used a red dot (cmore) it was mounted forward and I liked it.

Thanks.

 

[375nm]

Forward mounting Eotech

The Eotech won't co-witness with standard height irons if placed on an elevated rail. IIRC, mounting the Eotech in such a way will place the irons in the lower 1/3 of the HUD. When both are zeroed to the same distance, the reticle will not line up with the irons.

If you have flip up front and rear BUIS, lack of perfect co-witness probably isn't a big deal.

Another option would be to spend a little more and add a KAC Free Float (FF) RAS or KAC RAS II.

Either one of these would add a solid forend mounting surface for the Eotech while remaining the same height as the integral receiver rail. Well--The FF RAS would. The RAS II has that hump where it attaches to the upper receiver.

Bushmaster just came out with their own FF tube with integral rails. It's about $100 cheaper than the Knight's, but too new to find any reviews/evaluations on. Looks solid. If they're machining it themselves it's probably a pretty nice component.

I've tried my Eotech 552 (AA model) mounted forward of the upper receiver on a KAC M4 RAS--Made the rifle a bit nose-heavy, IMHO. Balance and ergonomics (access to the controls) is better *for me* with the Eotech mounted as far forward as possible on the upper receiver's rail.

RE: Eotech 2d reticles. Something that I noticed that I haven't seen anyone else mention--because it is a hologram, the Eotech reticle stays the same size regardless of the eye's distance from the reticle. This has the interesting effect of making the reticle appear to grow larger as the distance between the HUD and your eye is increased. As the HUD "shrinks" into the distance, the holgraphically projected reticle remains the same size, leaving less and less room between the 65moa ring and the outer edges of the HUD window. Probably not of much concern considering the range of distances available on an upper (even with a forend rail)--But something to keep in mind.

 

[375nm]

Forward mounting Eotech

The Eotech won't co-witness with standard height irons if placed on an elevated rail. IIRC, mounting the Eotech in such a way will place the irons in the lower 1/3 of the HUD. When both are zeroed to the same distance, the reticle will not line up with the irons.

If you have flip up front and rear BUIS, lack of perfect co-witness probably isn't a big deal.

Another option would be to spend a little more and add a KAC Free Float (FF) RAS or KAC RAS II.

Either one of these would add a solid forend mounting surface for the Eotech while remaining the same height as the integral receiver rail. Well--The FF RAS would. The RAS II has that hump where it attaches to the upper receiver.

Bushmaster just came out with their own FF tube with integral rails. It's about $100 cheaper than the Knight's, but too new to find any reviews/evaluations on. Looks solid. If they're machining it themselves it's probably a pretty nice component.

I've tried my Eotech 552 (AA model) mounted forward of the upper receiver on a KAC M4 RAS--Made the rifle a bit nose-heavy, IMHO. Balance and ergonomics (access to the controls) is better *for me* with the Eotech mounted as far forward as possible on the upper receiver's rail.

RE: Eotech 2d reticles. Something that I noticed that I haven't seen anyone else mention--because it is a hologram, the Eotech reticle stays the same size regardless of the eye's distance from the reticle. This has the interesting effect of making the reticle appear to grow larger as the distance between the HUD and your eye is increased. As the HUD "shrinks" into the distance, the holgraphically projected reticle remains the same size, leaving less and less room between the 65moa ring and the outer edges of the HUD window. Probably not of much concern considering the range of distances available on an upper (even with a forend rail)--But something to keep in mind.

 

[Cableman]

I mounted a Bushnell Holosight - same as the Eotech - on my Bushy 16" Flattop and it works great. I have the standard front sight and the Holosight does co-witness with the front sight. I just used the flatop rail and mounted the Holosight as far forward as possible. It works great and is light weight to boot.

 

[sanchezero]

I'm also toying with the idea of a SIRS setup. Money is certainly an issue, but I haven't ruled it out.

I guess I'll also have the same problem with it as the swan sleeve?

Thanks all .

 

[hksw]

I see.

For a cheap alternative, Fobus manufactures a replacement front handguard for shorty ARs. The particular handguard has a molded in Picatinny rail that you can mount various accouterment. Since the front handguards are split equally, you can actually replace both halves for a top and bottom rail configuration. Mounting an EOTech on the top rail should allow co-witnessing.

Now, I'm not pushing this option, but it is out there. I have seen samples at gun shows and the ones mounted on the ARs seem tight and sturdy and immobile. I have considered getting one for my DPMS Lo-Pro Classic as it would allow me to mount backup fold down rear and front sights in case my EOTech 551 lost power. (The Lo-Pro Classic is a flattop and doesn't have a front sight.) However, examining the handguards of the Lo-Pro, I'm not entirely convinced that if I put the Fobus on that it would be as solid as the ones I saw at the shows.

Like you, I've considered getting the SWAN Sleeve #38 Super Extended for the backup sights but then the flip up rear sight probably wouldn't co-witness with the EOTech. Maybe a #36 Super Extended with a #40 rear sight would raise it high enough to co-witness. The only problem for me is the nees for a short flip up front sight. Fulton is the only one I know that sells one but for a high price. By then, though, the entire sight system would probably be too high to shoot comfortably that it wouldn't be worth it.

 

[sanchezero]

Yeah...

I just saw that Fobus thing. I'm gonna stick with something other than plastic...

I can't believe that Eotech would put together a unit like they have and make it dysfunctional with what is seeming to be the standard in mounting.

 

[hksw]

I meant I have a 511, not a 551. Me + typing = not good.