M*CARBO Brotherhood

Co witness red dot w/ M-Carbo rear peep and sight mount?

This is my 1st post.

I have never owned a firearm before. I’m new to all this so please bear with me through some of my questions. They may seem dumb to you but hey… if ya don’t know, ASK.

I have the M-Carbo rear peep sight on my S2K. I also have the flip up optic mount.

I now have 2 optics and just purchased a 3rd. I’m trying to get this right.

1st optic was a cheapo amazon reticle sight.
(HIRAM 1x22x33 Holographic Reflex Scope Sight with 4 Reticles Red and Green Dot with Red Laser)

Surprisingly enough, the Hiram reticle sight worked! Mounting the sight on the S2K rail, I was able to absolute co witness. I was NOT able to close (fold) the gun.

I purchased the rear peep and optic mount from M-Carbo as well as a few other goodies from them.
With the flip up optic mount, the reticle optic is too long to fit and the optic is too high to even see the S2K sights.
This optic did not work out on the Hi Point .45 Carbine. It was way too high for the factory sights but not OVER the sights.

I then purchased a Feyachi RDS-22 Micro Red Dot Sight - 2 MOA Compact Red Dot Scope 1 x 22mm

This seems like a much better sight and I got it because of it’s low base. I mounted to to the optic mount and it sits too low. It’s usable (I think) but it’s really low. The factory iron is close to the top of the optic.
This optic "as is’ fits great on the Hi Point .45 Carbine with great absolute co witness. (Might be its new home)

I purchased a Sig Sauer Romeo5 (has not arrived yet). I got the lower priced one with the low rise mount included.

Will this work?
Will this do what I’m looking for which is absolute co witness on the flip up mount?

Like i said…
I am new to all this so please bear with me.

Thanks in advance.


Have you considered a low rise mount for your optics. Front site posts vary in length, not much, but there can be variance. UTG makes a good low rise and its inexpensive. What I would like to see is maybe a flip up front site post option by MCarbo. This might mean that a different handrail would have to be developed that would still allow the S2K to be folded.


I saw them online and thought about getting one. It would have been waaaaaaaay less expensive than buying the Romeo5

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This is what i got and it works great for low profile red dot sights plus it gives you a qd lever.


I, and many others, have the Romeo 5 on the sub 2000. It works very well.

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@DJCity … welcome.

Have you backed up far enough to figure out the “why” component of the “cowitness” you seek? I don’t doubt that you have; however, it’s a trendy pursuit and many folks are dissapointed once they achieve their cowitness’g. The topic has been discussed and considered from many angles.

The sub 2000 front sight takes a healthy bite out of a cowitnessed sight picture so you can read several stories about folks struggling to get their sight picture back.

The little magnifying glass icon at the top right of this page is the search feature. If you search cowitness and co witness and red dot and … you’ll get a chance to share a variety of experiences.


Thank you.

The “why” in a nutshell is because i have no experience otherwise.
I’m brand new to this.
My train of thought is an optic will be a very helpful tool and the sights that come on the weapon should be able to reference the red dot and vice versa.

I will continue to research but I’m pretty much learning all this on my own.


I thought " lower 1/3 co witness" was a desirable standard until i saw how it looked. I hated it. The riser my romeo came with gave that lower 1/3 right when mounted on top of the sub. I bought the exact quick disconnect riser @iamrodo shows above, and i now have a clear view through the Red dot sight with nothing in the way!


Unless the optic has a reticle that stays visible when not powered, my feeling is iron sights and an optic should be treated as separate animals. Absolutely get the irons zeroed before you mount the optic, then zero it on its own. Anything mechanical can fail, so the iron sights MUST work every time and a QD mount is a requirement.


I got the 0.5" UTG mount. It raises the optic too high.
Is there a riser mount less than 0.5?

I should be receiving the Romeo5 sometime this coming week. I hope it sits well and does what I’m looking for.


I bet not, but “full disclosure” , im just too lazy to double check. :wink:


This is the optic without the riser.

Sight is too close to the top of the optic for my liking.

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Thst just makes the red dot downright pointless.


Does the Romeo5 Co-wittness with the S2K front sight and M-Carbo rear peep sight while mounted to the M-Carbo optic mount?

Does anyone have a pic looking down the sight so I can see what I should be looking at with the Romeo5 in this configuration?

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I just got my Romeo5.
I’m happy so far. With the low mount, the co witness is what I wanted it to be.



Hope this help’s

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Anyone tried the vortex sparc 2 ar ?

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@DonRozon, I have tried the spark II. I thought it worked great. It has multiple riser options for whatever you like. I’ve never tried the space ar though.

For what it’s worth, I have switched to the bushnell lil p. It’s the smallest prism sight I’ve ever seen and the glass is crystal clear!


While I have little experience your particular firearm and am pretty much a lurker on this message board, I did want to say welcome to the world of firearms. There are no dumb questions, especially when it comes to firearm handling. I see lots of good answers in this thread and hope you find what you’re looking for in an optic. No one has mentioned their optics yet but you might want to look at Primary Arms selection. I have one of their MicroDot first generation red dot sights and have been very pleased with its performance. I run it at 1/3 co-witness on one of my ARs. Once again, welcome, keep calm and carry on.

I co-witness my Romeo 5 off the top of the front post sight. Using the peep sight to co witness isn’t as accurate,IMO. The dot is basically the same diameter as the front post,I just sighted it in where the dot sets on top of the front sight post and it’s dead on out to 75 yards. That’s the farthest that I’ve shot it,but I can keep all shots on a 8" steel plate at that distance shooting off hand.