AR15 rail/BUIS questions..

[CMEBoston]

So I just picked up a bushmaster with a bushnell trophy scope. I want to add a BUIS in the rear. Because of the size of the scope I don't have the room for a BUiS so I want to add a rail / riser. The only rails I have found are the GGG scout and Hahn precision. Hahn makes a scout rail with a BUIS and a BUIS cut rail(like the GGG)

Are these my only options? Anyone have an opinion on either of the products listed or have any other reccomendations? Also will the riser give me 2/3 cowitness? I'm not sure I like the absolute cowitness now anyway.
First pic is my rifle,
Second is one I found online with the same optic and a BUIS, but the optic is not grabbing the whole rail.





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[Independence Arms]

I would change out the fore end, with a quad rail, and move the bushnell forward to accommodate the rear BUIS.

If your interested, I just changed mine out to a rifle length YHM, and I have a spare Troy Ind. carbine length rail that would look nice!

 

[CMEBoston]

I would change out the fore end, with a quad rail, and move the bushnell forward to accommodate the rear BUIS.

If your interested, I just changed mine out to a rifle length YHM, and I have a spare Troy Ind. carbine length rail that would look nice!

I am resisting a quad rail like the plague!!!! I really want to keep the handgaurd that is on it. Aesthetics play ah huge role for me with my Firearms.....just look at my M14 in my avitar, the slotted HG is not very practical but it looks sexy!!!!

No seriously I would like to keep the existing handgaurd and A2 sight post.

 

[Independence Arms]

Ok, just a suggestion.

 

[CMEBoston]

Ok, just a suggestion.

I appreciate it, but I dont plan on mounting a Myriad of accessories on her. I may put a section of rail along the bottom of the HG to facilitate a bipod or forgrip.

 

[P-14]

I used the GG&G Scout Riser on my first AR project to move the Millett DSM 1-4x red-dot forward so I could add a BUIS and have proper eye relief. This build also had an A2 fore end. The riser added significant weight to the rifle, but did the job. Eventually, I replaced the fore end with a free-floating quad-rail fore end that had a "bridge" to the upper rail. This reduced the weight and improved the accuracy of the rifle. In addition, I have put the optic where I wanted (more forward) and the BUIS at the back of the upper.

YMMV.

 

[CMEBoston]

I used the GG&G Scout Riser on my first AR project to move the Millett DSM 1-4x red-dot forward so I could add a BUIS and have proper eye relief. This build also had an A2 fore end. The riser added significant weight to the rifle, but did the job. Eventually, I replaced the fore end with a free-floating quad-rail fore end that had a "bridge" to the upper rail. This reduced the weight and improved the accuracy of the rifle. In addition, I have put the optic where I wanted (more forward) and the BUIS at the back of the upper.

YMMV.

What was the co-witness like? Weight is not really an issue, the rifle is heavy as it is (Hbar, solid stock with storage) so I don't think a few more ounces is gonna kill meson you still have the rail and is it for sale?


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[P-14]

I did not co-witness the BUIS. I opted to quick release the optic and use the sights without it present if needed. I still have the rail, but am not ready to part with it at this time. Sorry.

 

[CMEBoston]

thanks, that was the other question, will the sights still co witness with the riser? Right now I have absolute co witness but would perfer 1/3. I just cant figure out how far I need to go to get 1/3 ..... or figure out how to QD the bushnell if its possible. as you cn see I am quite green to optics on an M4 platform.....Last AR had a fixed carry handle, and my Colt has a detachable that I use.

 

[P-14]

I have an A2 front sight mounted on the rifle as well and with the riser, the front sight was 1/3 lower when the optic was on 1x. Because of the length of the Millett, I could not use the BUIS unless I removed the optic. It was what it was. That's why I eventually moved to the free-float fore end.

 

[CMEBoston]

I have an A2 front sight mounted on the rifle as well and with the riser, the front sight was 1/3 lower when the optic was on 1x. Because of the length of the Millett, I could not use the BUIS unless I removed the optic. It was what it was. That's why I eventually moved to the free-float fore end.

Great thanks! so I am on the right track, the GG&G will do what I need it to........

 

[CMEBoston]

So a follow up, I actually order a YHM riser/extender and a Magpul MBUS rear sight (gen 2) but found out along the way that the bushmaster sight post is too short to use with a BUiS, so I needed to order one that was .040 taller than the original...


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[MassMark]

Even though that Bushnell is a 1x, it has an identical physical profile to an ACOG. I think co-witnessing that optic is going to be a challenge, if not downright impractical. The optic as it is, looks high enough to tuck a folding BUIS underneath it and raising it further, will in my opinion, deliver proper cheek-weld issues. Generally with an optic like this, BUIS are added in case your optic goes down and you can shed your optic and use your irons. In most, (if not all) co-witnessing set-ups the BUIS are used to co-witness an optic like an Aimpoint.

 

[CMEBoston]

Even though that Bushnell is a 1x, it has an identical physical profile to an ACOG. I think co-witnessing that optic is going to be a challenge, if not downright impractical. The optic as it is, looks high enough to tuck a folding BUIS underneath it and raising it further, will in my opinion, deliver proper cheek-weld issues. Generally with an optic like this, BUIS are added in case your optic goes down and you can shed your optic and use your irons. In most, (if not all) co-witnessing set-ups the BUIS are used to co-witness an optic like an Aimpoint.

thanks for the heads up, currently the Optics "dot" is just about on the FSP, and when my eye is a little above the optic the dot is below the FSP, obscuring the target. so in order for this setup to work for me as it is ( no riser) i have to put my head down to the stock alot further than is comfortable. that is the main reason behind getting the riser. Basically the optic is too low for my fat head and uncomfortable to shoot. are you implying I will not get an sight picture with the irons through the optic with it risen 1/2"? I would just want to use the Irons when the optic fails, and this particular optic has no QD. could I get a QD for this Optic?

 

[MassMark]

thanks for the heads up, currently the Optics "dot" is just about on the FSP, and when my eye is a little above the optic the dot is below the FSP, obscuring the target. so in order for this setup to work for me as it is ( no riser) i have to put my head down to the stock alot further than is comfortable. that is the main reason behind getting the riser. Basically the optic is too low for my fat head and uncomfortable to shoot. are you implying I will not get an sight picture with the irons through the optic with it risen 1/2"? I would just want to use the Irons when the optic fails, and this particular optic has no QD. could I get a QD for this Optic?

I think it will be a challenge. I don;t honestly know if I'd invest in risers and QD attachments for the optic you have. It's easy for me to spend other people's money, but I'd sell that Bushnell, or save it for a .22, get one of these and be done...It's set up to be co-witnessed, (the Bushnell is not and I really don't think it was ever intended to) and is solid, reliable, (battery life left on is something like 3-years):

http://www.laruetactical.com/aimpoint-pro-patrol-rifle-optic-w-mount

I think forming the Bushnell into something you want it to be, or making it perform outside it's intended purpose my be frustrating....

 

[CMEBoston]

I think it will be a challenge. I don;t honestly know if I'd invest in risers and QD attachments for the optic you have. It's easy for me to spend other people's money, but I'd sell that Bushnell, or save it for a .22, get one of these and be done...It's set up to be co-witnessed, (the Bushnell is not and I really don't think it was ever intended to) and is solid, reliable, (battery life left on is something like 3-years):

http://www.laruetactical.com/aimpoint-pro-patrol-rifle-optic-w-mount

I think forming the Bushnell into something you want it to be, or making it perform outside it's intended purpose my be frustrating....

I don't intend the Bushnell to be any kind of combat optic, nor do I intend my Bushmaster to be a combat rifle ( that's what the Colt is for) perhaps I am not fully understanding the situation. I dont mind the bushnell, but it is uncomfortable for me to shoot the rifle as the optic is to low for my liking, hence the riser.
I am not about to put a $400 optic on a $500 rifle.........................
the bushnell came with the rifle, i like the optic and am just trying to get it to work for me, not trying to make it something it is not. Actually every review I have read on the bushnell has been positive, it is intended for a shotgun so I would think it could handle 5.56 with a muzzle brake. my other thought is to ditch the A2 front sight the in wont be in my FOV, but I also like to use the carry handle sights for CMP shoots. my question remains, if I raise the optic 1/2" will it be too tall to use iron sights? if so I will just use the riser to get the optic high enough to fit me comfortably and not have the A2 sight obscure my target.

 

[MassMark]

I don't intend the Bushnell to be any kind of combat optic, nor do I intend my Bushmaster to be a combat rifle ( that's what the Colt is for) perhaps I am not fully understanding the situation. I dont mind the bushnell, but it is uncomfortable for me to shoot the rifle as the optic is to low for my liking, hence the riser.
I am not about to put a $400 optic on a $500 rifle.........................
the bushnell came with the rifle, i like the optic and am just trying to get it to work for me, not trying to make it something it is not. Actually every review I have read on the bushnell has been positive, it is intended for a shotgun so I would think it could handle 5.56 with a muzzle brake. my other thought is to ditch the A2 front sight the in wont be in my FOV, but I also like to use the carry handle sights for CMP shoots. my question remains, if I raise the optic 1/2" will it be too tall to use iron sights? if so I will just use the riser to get the optic high enough to fit me comfortably and not have the A2 sight obscure my target.

Okay...Short answer: Get a 1/8 riser and it should co-witness the bottom 1/3. The BUIS will be packed against the rear of the scope, but if that's fine with you - then it's fine with the rest of the world...Cheek-weld should be interesting, but it looks doable....

 

[CMEBoston]

So 1/2 is way to tall, and the optic base will block the rear sight ? Obviously I can't get the rail to cantilever over the HG with 1/8, so the BUIS will be under the optic requiring removal. That sucks, and what I was trying to find out, thanks.


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[CMEBoston]

A follow up, I got the MBUS and riser today, you can align the iron sights but it is close to the bottom of the optic picture. I like the extra 1/2 inch and the cheek weld with my big head is fine.



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[CMEBoston]

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