M*CARBO Brotherhood

Front and rear sight removal sub2k

I have long been an iron sight guy. I always want irons as back up. the sub2k and mcarbo optic mount dorve ne to make a bold choice.

The optic mount is one great piece of kit . In my humble opinion the only viable solution for quick deployment of optic on sub2k.

I have been one of the unfortunate to have my irons canted to the left with my holosun HS403B

I have tried the shims and that was a less than stellar outcome. I also wanted to have 1/3 rd cowitnes option which I was never able to find.

Finally I just realized that the sight picture was to cluttered for .my eyes.

In a final attempt to get the best solution I removed the front and rear sight.

Now, I have a very clear field of view that is quick to acquire targets and get off accurate snap shots.

I am still a bit nervous about not having back up irons but I think with training decent shots out to 50 yards should be easily attainable.

I am much happier with this configuration.


I have left my irons on for backup, but do normally fold down the rear sight when using my HOLOSUN on the Mcarbo Optic mount. It did take some trial and error to get my Holosun on the optic mount centered with the irons, but I did it.


How? Did you get that accomplished?



How did I accomplish what? Folding down the rear sight? That was the easy part, bought the MCARBO rear sight. As far as centering the optic, that was a little more tricky. I had to put spacers in the top two holes where the optic mount mounts to the forend and then get longer screws. I used small washers totaling about 1/32 thick. This centered the optic left to right with the iron sights. As far as height, it is not a true cowitness. The irons are just slightly higher than dead center of the optic when using the short mount that came with the Holosun. Probably closer to an upper 1/3 cowitness. Here’s a couple pictures, but really can’t see much because this one is a 65MOA circle/2 MOA dOT sight. This is the head of an IDPA practice target I shot today @ 25 yards with it.


A pic with the rear folded down. It’s actually better than it looks. I’m having problems getting the camera in the right position for the pic.


Yes I meant getting the optic centered. I guess I should try the 1/32 washers. Did you get them from lowes or home depot?




I had set up my recent 22 Custom AR Platform with a Sig Saur Romeo 5 and co-witness. I am adding iron sights as a ‘back up’ myself. If it doesn’t work out, I am sure that they will find a ‘new home’ on my next AR 15 Pistol Build. I am sure that I will come up with that ‘same challenge’ when it comes time to building that sub2k??? @ChrisNelson better get with R and D soon and start designing that 80% kit soon! I am starting to get an ‘itch’ to add it to my arsenal…:grinning:


@Silverback i got em from ACE HARDWARE Paul, more of a selection in thickness, and i can buy as many or as few as i need. 1 or 1000.
on the keep. remove BUIS question I always refer to the same meme, somewhat silly , but the picture gets the point across. I have busted, fogged, bounced way more scopes, and never banged a iron sight to where it was off…


Good point. I’m going with red lion foldable front sight. It will give me clear sight picture thru red dot , dont have to worry about correcting left cant of optic mount , standardized ar style front sight and buis as needed. Thanks for the push to keep the irons I feel better now.

Now I think I need new firing pin. I have been experiencing some light primer strikes recently.



I am so glad your post convinced me to dig a bit further and get the red lion front sight.

Super quick shipping. Excellent high grade product. Easy to install. Well worth the price. Sure I would like it to be cheaper but you can see and feel the quality.
Now I have clear red dot view ad quality AR ike function front sight.

I am taking it to the range tomorrow getting them sighted in.


You can also snip the ears that unfold the rear sight when you open the Sub up. That lets it stay folded out of the way until you want it deployed


Thanks but I already have mcarbo rear peep installed. I can just push down when deploying optic.


@Silverback Hit the range yet Paul?


Life got in the way yesterday.

Just got back from range today. Great fun.

The red lion sights are so much easier to use. The ar sight tool provided also fits the lateral adjustment holes so it really makes getting it dialed in a pleasure.

Dialed the redot in to.match irons then folded them down and went to town.

I would like tonbe.more accurate at 100 yards but minute of bad guy is good to go.

I am sure if I had fix power scope hundred yard groups would have been better.

25 and 50 yards nice and tight.

Super happy with this set up.

Perma grin


It may be blasphemy to mention a competitor’s product in the MCARBO forum but I replaced the OEM front sight with a Red Lion Precision Gen 2 Sub2000 Folding Front Sight and the OEM rear sight with the MCARBO folding back sight. They matched up with zero adjustments necessary, I used the shorter mount for my Holosun red dot for full co-witness. Both iron sights folding away and out of the picture when I use the optic.


Exactly my experience


@Cobbler00 @Silverback I run the same on my Gen 1, except my Red Lion is a fixed position only( the fold-able sight wasnt out yet.)
now im trying to figure out how to Run the HK style fold-able sight on my Gen 2 SUB
I have the Troy industries one on my 300 Blackout,
and I really Like that style with a tritium insert…


I haven’t taken my 300 blackout yet. I have been so busy setting up my other guns.

I am beginning to wander off it’s even worth it. …
Wait did I say that out loud?


Cant wait to spend time with it.
10 inch barrel with deadfoot arms folding stock.

You can shoot while folded. Special bolt setup. Lifetime warranty GI owned company.


Sorry I didn’t get back sooner. I got the washers from a little local True Value hardware. Actually used a lock washer, smaller O.D. Lowes and Home Depot didn’t have anything small enough.


I’m kind of the opposite. I prefer an optic on my rifles (except for the Milsurp ones). The Sub2000 I still have factory sights since I don’t see using it past 50 yards and the factory sights will be good enough to handle that distance.