Installing a new handguard on rifle with front sight

bcsteve

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Question for the AR gurus/builders. I have a stock Stag Model 2 AR (16" barrel, regular handguard with front sight) and I'm thinking of modernizing it with a BCM KMR (probably the 13") or similar. What will it involve exactly? Can I get away with cutting down the front sight or will it need to be replaced with a low profile gas block? Thanks.
 
Midwest offers a 2-piece drop-in keymod handguard which allows you to keep your existing delta ring and front sight post.

http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_ID=1204

We haven't gotten them yet, but hope to have them in January 2015.

BCM KMR and almost all of the other free-float KeyMod handguards come with their own proprietary barrel nut which requires you to strip down the barrel and replace your gas block with a low profile one.

You could chop down your front sight block, but you have to make sure you have the clearance. The KMR only has an internal diameter of 1.2" to 1.3".
 
You can cut the gas block down, if it fit underneath the hand guard. That's how I have my 10.3 Stag with a YHM Diamond spectre length set up. Pinned gas blocks are stronger then set screw type.
 
You will have to remove the FSB by knocking out the 2 taper pins. Remove the original barrel nut and put in the new barrel nut proprietary to the KMR.

You can shave down the original FSB with a dremel tool until it fits under the KMR. If I am you I will just shave it down, or get a smith to do it if you want it to be prettier.
 
You need proper punches to get the 2 pins out on most AR's... Start off with a taper punch, somebody holding the upper on a front sight block and use a SLEDGEHAMMER (no joke).. Once you get the pins moving, get a straight punch and finish the job.
 
You can cut the sight off, it will work, since you are going to taking the whole barrel assembly off any ways, might well do it properly.

A low profile gas block is a $50 part, cheaper if you buy it off EE, it is even better when you flip that front sight block on EE to recoup the half the cost.
 
I shaved my FSB down to a low profile. Took me an hour with a hacksaw, a file and a piece of sandpaper. Knock out the taper pins and go to work. Then hit it with some Blue and oil it up.
 
Just cut the gas block down and shape it.

i3s8qx.jpg


And shape it into a low profile gas block.

Gas_Block1.jpg


All Troy industries rails and some Fortis and Samson rails use standard barrel nut.

Example Fortis Rev:

REV-14-E-640x480.jpg
 
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