Front A2 sight base"F" marked question?

[george_995]

I am currently looking to install an A2 front sight base .750" for my maten build.

http://www.bravocompanyusa.com/AR15-Front-Sight-F-Marked-p/front%20sight%20base%20-%20f%20750.htm

Bear with me because I have a two part question. I know the item I have linked needs to be reamed and pinned, "permanent".

First off I have a 18" select barrel from Rainiers w' .750" at the gasblock, I have a jp 15.5" forearm forearm mounted covering the gas block. I am going for the dissapator look w/ my rifle and I know I am going to use irons mostly. Question is will there be a problem mounting the sight base forward on the barrel were the diameter is .730"(confirmed by caliper)?

Part two, is most bases I have researched are 1.870" long, I measured available space left on the barrel and found that 1.870" is a hair near the crush washer for the flash hider. Any ideas?

My other option would be jp's a2 style sight base, but is expensive and not permanent.

http://www.midwayusa.com/product/413559/jp-enterprises-gas-block-with-adjustable-a2-front-sight-ar-15-lr-308-standard-barrel-750-inside-diameter-stainless-steel-matte

Caliper set at 1.870"

more pics.

Ultimately this is what I am looking for with my rifle. This is not my rifle, found in search on BrianEnosforum.com.

better pic in link.

http://www.brianenos.com/forums/index.php?showtopic=141084

[carbon9]

I would just go with the clamp on JP A2 front sight or the Armalite version for a bit less $$$.  Also, I personally wouldn't pin it.  I have ran several setups like the BEnos pic and haven't had any of them shift even after getting tossed into dump bins or snagged on ports.  The Armalite you may have to shim it with a beer can or other shim to avoid stressing the legs too much when you tighten it down.  The JP you may have to grind the slot between the leg screw holes wider so it will clamp tightly enough on that thin of a barrel but it is solid and a bit better built then the Armalite.  The JP can take the stress of being tightened without shimming.  Realistically I would be comfortable with either one it just depends on aesthetics and your wallet.  The JP is 1.88" long, I am not sure on the Armalite.  You can run it right up the lip of the threads no problem and worst case scenario you can grind or notch your handguard a touch.  Or get one of the CarbonArms.us carbon fiber tubes that fit the JP Barrel Nut and cut it to length.  This is gonna be a good looking rifle. <thumbsup>

ETA:http://www.armalite.com/ItemForm.aspx?item=EU0240NMPKIT&Category=07033031-2a2e-439c-a701-edf0d7327c93

[george_995]

Thanks man. I used the link provided <thumbsup>. One thing though, the link provided has no detail on bore diameter for the item. Will have to call before ordering, that being said I am going with the armalite because it is less expensive. I cross posted this and some mentioned notching the handguard, this isn't an option for me. I would rather grind on the $40 sight base than the $180(roughly) handguard. <lmao> . Not loosing any sleep over this. I appreciate your insight. Thanks :ecs:

[Robocop1051]

Don't do a standard A2 with taper pins. The project will cost more than the parts you are installing.

Personally, I like the A2 style flip up sight

Why put on a fixed sight? Especially when there are such high quality flip sights available. I'd get the A2 above and switch out the front sight post.

I just did this exact task for my 300blk. The difference between .750 and .730 is considerable. The beer can shim worked for me, but I was able to hide the shim under the gasblock and inside the handguard.

Here is the plan I had if the shim didn't work:

1. Get a 3/4" wooden or metal dowel from the hardware store.

2. Buy a clamp on style gas block.

3. Remove the tightening screws from the GB.

4. Place the dowel in the GB, then tighten the GB onto the dowel in a bench vise.

5. Use a metal saw or rotary tool, and saw a 1/32" gap (about the with of the blade) where the two halves meet.

6. Check for fit, repeat if necessary.

[survivalshop]

Why not just go with a BUIS ? 

The MBUS I have on my 16" 308 work just fine & there are a bunch of other brands available . Unless you just like the look of the A2 sight tower , the inch or so longer sight radius , will not make much difference between the two .

[george_995]

Why not just go with a BUIS ? 

The MBUS I have on my 16" 308 work just fine & there are a bunch of other brands available . Unless you just like the look of the A2 sight tower , the inch or so longer sight radius , will not make much difference between the two .

Basically what you have stated. I am going for something different, and with my rifle I am gonna use irons 90% of the time. So shadows being cast w/ optics is not a concern. I have a troy gas block mounted sight on one of my ar15's. I originally was going to get another gas block w/ rail (jp ent. .750")and mount it in same place, but got to thinking it would look bulky/stupid.

I purchased the armalite clamp sight base. We will have to see were this goes when I receive it. I appreciate everyone's input.

[george_995]

Don't do a standard A2 with taper pins. The project will cost more than the parts you are installing.

Personally, I like the A2 style flip up sight

Why put on a fixed sight? Especially when there are such high quality flip sights available. I'd get the A2 above and switch out the front sight post.

I just did this exact task for my 300blk. The difference between .750 and .730 is considerable. The beer can shim worked for me, but I was able to hide the shim under the gasblock and inside the handguard.

Here is the plan I had if the shim didn't work:

1. Get a 3/4" wooden or metal dowel from the hardware store.

2. Buy a clamp on style gas block.

3. Remove the tightening screws from the GB.

4. Place the dowel in the GB, then tighten the GB onto the dowel in a bench vise.

5. Use a metal saw or rotary tool, and saw a 1/32" gap (about the with of the blade) where the two halves meet.

6. Check for fit, repeat if necessary.

I book marked that sight I have seen it before, pretty bad ass. When the time comes to mount the sight base I am referencing this post. Thanks.