Red dot on ar with fixed front sight

[DSmith78]

My ar has fixed front sight with flup up rear. I want to put red dot scope on it but keep the fixed sight on the front. What height mount you recommend? Any links to a goid mount be helpful also

 

[Bigtanker]

I don't remember the exact height of my riser but I prefer to have it co-witness dead center.

Most are offered as a "lower 1/3 co-witness". The lower 1/3 co-witness riser that came with my red dot, the front post was barely in view. Looking at other offerings, it looks like it depends on what sight you use. This is from a quick search.

Geissele is 1.41" for co-witness and 1.57" for lower 1/3 (based on an email response I received from them). ADM is 1.52" for co-witness and 1.69" for lower 1/3.

 

[CraigAPS]

I have the same setup--Magpul rear, A2 front. I have a .83" height riser and it gets me absolute cowitness, which what I prefer.

 

[Ggreen]

I don't remember the exact height of my riser but I prefer to have it co-witness dead center.

Most are offered as a "lower 1/3 co-witness". The lower 1/3 co-witness riser that came with my red dot, the front post was barely in view. Looking at other offerings, it looks like it depends on what sight you use. This is from a quick search.

Depends on the dots housing too. Most dots use aimpoint micro mounts, but holosun are slightly different dimensionally. Generally the dot has enough adjustment to compensate for the differences in aftermarket mounts.

Lower 1/3 let's you have a clearer view, and generally easier to aim with ear pro on.

Absolute basically puts a dot on your front sight post.

What red dot do you want? Id just get a dot with a mount you like.

 

[DSmith78]

Looking at the sig red dot

 

[Forkmylife]

Trijicon MRO with a Lower 1/3 mount is my favorite.

 

[nipprdog]

Looking at the sig red dot

if its the romeo 5, it will be absolute co witness.

 

[Hookeye]

Leupold rds is absolute cowitness.

 

[firefighterjohn]

if its the romeo 5, it will be absolute co witness.

I agree, got several Romeo5s and they work great with fixed front sights. They are relaible, light weight, and the MOTAC feature is very handy.

 

[Ruger_Ronin]

Absolute co witness makes zeroing a breeze too. Numerous times have I removed an optic (Eotech) for rifle maintenance and maintained zero after reinstalling. The lollipop trick as it were. As long as irons are good, you'll be within a click or 2 at worst. I prefer an A2 fsb over flip fronts anyway.

Rear: MBUS pro
Front: A2
Optic: Eotech 558 w/ Vortex vmx-3t

 

[avboiler11]

I personally like absolute for my RDS.

 

[Hohn]

ALso depends on your FSB. If you have a true A1/A2 height it is slightly different than a flattop ("f" marked) FSB. The nweer F marked units are taller and would required less height in a RDS mount to give true absolute cowitness.

 

[climber1218]

I simply cut off the front sight and went with 45 degree offset backup sights since I like my red dot to sit as low as possible for a consistent cheek weld!

 

[climber1218]

My other option would have been to replace the gas block/front sight completely, but that would have involved spending money!

 

[Ruger_Ronin]

I simply cut off the front sight and went with 45 degree offset backup sights since I like my red dot to sit as low as possible for a consistent cheek weld!

 

[Ggreen]

This is the original low pro gas block. Still a valid choice on a pinned barrel

 

[Jones1776]

The sig romeo will be a absolute co witness just center the dot in the middle of the post and right on top of it and you will be really close to being dialed in if your sights are already sighted in

 

[Fixer]

I second the Low Pro gas block. One can be had for about $20. I currently have 45 canted flip up sights and a Vortex Strikefire 2 set up on one of mine. The canted sights are more natural to use than I expected. I didn't want the front sight to obscure the red dot sight picture. Just my preference.

 

[Zephri]

I personally prefer a fixed front and folding rear for anything home defensy but maybe I'm a traditionalist at heart . These are both absolute cowitness.

 

[palerider0485]

The two above pictures are both nice outfits. I like my eotech on my rifle with fixed front sight. If you co witness keep both eyes open. You won’t notice the front sight is there.