My AR-15 rebuild is temporarily SNAFU. I got my Daniel Defense MFR rail and I really like it (kind of wish I’d gotten the 13.5″ instead of the 10″ though). Like I’d hoped, the barrel nut is the same as the RIS-II. Good so far – no need to remove the gas block. Well, except… oops. When I thought I might have to take it off, I went to DD’s site to find out what kind of Loctite it uses for the screws. Major problem It won’t work with my gas block, which is also from Daniel Defense:
“* Does not fit within the MFR XS”
In my defense, I bought the gas block before the MFR rail was on the market. It’s pretty low profile so I had no reason to think it wouldn’t fit. No problem, I’ll just get a different gas block. I’m sure their Mk12 gas block will work, right? Wrong. OK, I’ll get a new rail. Geissele and LaRue both make quality stuff, they probably have a rail. Nope, at least not one as nice (or light) as the Daniel Defense MFR. So back to looking for a new gas block. Contacted Daniel Defense and they recommended one from SLR Rifleworks. It has two set screws and can also be pinned to the barrel. I’m not a big fan of set screw gas blocks. I don’t feel they’re as secure as the clamp-on style. Also, for this gun I don’t want to drill the barrel for a pinned block. So I guess I’ll order the gas block and dimpling tool and go from there. Not my first choice but it is what it is…
Maybe a new rail?
I did notice on DD’s web site that they have an XL version of the MFR rail that’s just a little fatter than the regular MFR. Maybe it is fat enough to work with the DD gas block? If so it will be tempting, but I already have too much money in this gun and I don’t want to drop another $279 for another rail. Besides, what would I do with my existing MFR? Sell it for a loss? I guess I could use it on an upcoming pistol build if the length is OK. Ah, the joys and frustrations of black rifle disease…
The Sept/Oct 2017 Backwoodsman Magazine had a good article on the AR 15. It’s nice to see them being open to the AR platform. I think the AR 15 is ideal for the Backwoodsman or Backyardsman. The article was positive, but the author left out the biggest point: How easy it is to build, repair, or reconfigure an AR 15. Just about anyone can do it, with no expensive tools (i.e. lathe) or specialized skills required. If you have average or better hand-eye coordination and you can follow simple instructions, it’s easy to work on an AR 15.
My AR 15
My AR 15 is one I built myself about 3 years ago. I put it together not really knowing what I wanted. The lower is configured as an A2 (fixed stock). I’m OK with that, but I flubbed the upper. Barrel is a Black Hole Weaponry carbine length HBAR. Heavy. Rail is a Daniel Defense RIS-II. Heavy. Flash hider is a BE Meyers 249. Heavy. The scope and mount are also on the heavy side.Because of all the heavy parts, the gun itself is heavy – not what I really want. The problem is I bought my parts without thinking about what I really wanted.
How to reconfigure an AR 15
Luck for me, it’s really easy to reconfigure an AR 15. My main goal was to reduce weight but keep the Black Hole barrel. Adding up the weight of things I could reduce gave me a total weight of 40.5 oz. (RIS-II 14.1, BE Meyers 3.1, LT104 7.1, and Viper PST 16.2). I started looking for lighter replacements. A Daniel Defense MFR is 8.4 oz. A plain A2 flash hider is 1.1 oz. lighter than the BEM 249. Aero Precision’s ultra light AR 15 scope mount is 3.3 oz. I can’t afford a new scope just yet, but Nikon M223 scope is an ounce less than my Vortex and gives twice the magnification.
Changing out the scope mount and flash hider is easy. The only potential issue is replacing the rail. Most of the time you’ll have to pull the gas block and tube to get the barrel nut off. In my case I hope it’s not an issue because my new MFR rail uses a similar barrel nut as the RIS-II. This is kind of a big deal to me because I used red Locktite to put the gas block on, and I don’t really want to take a torch to it. We’ll see when the MFR gets here later this week…
So what will I gain? Replacing the rail, flash hider, and scope mount take 10.6 oz. off the gun. That might not sound like a lot, but it should really change the feel and balance of the rifle.