View Full Version : Assitance with AR Build

July 2, 2012, 01:26 PM
Greetings all, I am presenting the following question to the forum. I am replacing a AR A2 upper with a flattop upper. Not a problem. The rifle had a rail system on it that attached in to the carry handle. Upon removing the rail system, I noticed the delta ring and spring are not present. The front sight is a fold down and the gas block is not the same on the standard A2 rifles. What I am in need of is a rail hand guard that will fit this rifle without any further modification. Any suggestions? I have pictures I can send to anyone who may be willing to help, if my description is not clear. Thank you.

July 2, 2012, 01:31 PM
Sounds a mighty lot like you have a free-float tube type fore end. You'll need a free-float wrinch and a strap wrench, I believe, to get these parts un-from-together. I don't know what type of gas block you have there, but it's either staked/pinned or screwed on in some fashion.

Since you already have the free-float thing going on, might as well stay with it. They're actually pretty good, and they make the corn cob looking rail tube which would probably come with it's own complete assortment of mounting parts that screw in.

July 2, 2012, 02:06 PM
Thank you I have attached a pdf that shows my problem area, I just need good direction of what kind of rail hand guard will fit this barrel. The previous rail hand guard, held on place by the carry handle and a half moon pieces tighten around the barrel nut.

July 2, 2012, 02:26 PM
Man, I hadn't looked at free floats in a long time and didn't know they'd gotten so expensive. Take a peek here: http://www.brownells.com/.aspx/pid=27474/Product/DIAMOND-PATTERN-FREE-FLOAT-HANDGUARD It looks like they come with everything you need to stick a new one on.

Also, remember to index and hold your front sight/gas block (which is made by YHM too) 7/32" off of that bbl shoulder so your gas holes will line up.

July 2, 2012, 02:45 PM
OK, so I am getting ready to order this Yankee Hill Forearm and End Cap, so this should allow the installation of a rail handguard on the existing weapon without any further modifiction and the the front of the handguard is compatabilte with the fold down sight that does not have a traditional handguard end cap? Thank you so much, I have been pulling my hair out with this.... I will post when I get it put together.

July 2, 2012, 04:41 PM
The top rail of the handguard should line up/be level with the flat top rail on your receiver.

Ok, I re-read your post, and yes, you are correct. If you get the correct length handguard that corresponds with your barrel and gas system length- you will be fine.

July 2, 2012, 07:02 PM
It's not that tough. Knock the stake pin out of the tube, loosen the two 10-32 screws on the bottom of the block/sling attachment, slide forward to free the tube.


July 3, 2012, 03:37 AM
From what I gather you had a free float tube type hand guard that had its own proprietary barrel nut. If that's the case and you want to go to a different hand guard then you will have to change the barrel nut to either a standard barrel nut or use what ever barrel nut comes with your new hand guard choice. Midwest Industries has a two piece free float hand guard that uses the standard barrel nut.

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July 3, 2012, 07:03 AM
That YHM hand guard well come with the barrel nut and all attaching hardware. You do not need to remove the gas tube from the YHM folding sight. Just unscrew the sight and slide the two off as one unit.

You may need special tools to remove the existing barrel nut/hand guard.

Install the new YHM hand guard and barrel nut, the barrel nut must be aligned so the gas tube fits through the slot on the barrel nut. You should have between 30 and 50lbft of torque on the nut, use moly grease on the threads. You may not be able to use a end cap with this setup. The end cap may not clear the gas tube. The end caps are normally used with low profile gas blocks that are covered by a long hand guard.

Google search this "ARMY TM 9-1005-319-23&P" Download the .pdf file.

This is the military manual on maintaining the AR rifle. It well have everything you need to know and spells everything out step by step. Lots of illustrations.

It well not have info on the floating hand guards or other aftermarket accessories.

July 4, 2012, 03:53 PM
Really like the YHM Diamond free-float handguard. You don't need a strap wrench, just torque the barrel nut until it's in the correct position as mentioned above.

Ditto on forget about the end cap...

July 5, 2012, 06:10 AM
A few hours after I made to above post I received my Midway order, a Yankee Hill Machine Todd Jarrett tube. I ordered a rifle length for a 16" build I had going.

The YHM barrel nut well except a GI barrel nut wrench. Mine lined up at about 40lbft of torque. The tube fit over my low profile gas block and has two anti turn screws that center the tube and then you tighten the lock ring.

The end cap is available in two different inside diameters, I ordered the smaller of the two. This well slide over the A2 flash hider and dresses the end off very nice. It shows the tube is perfectly centered, something that you don't always get with tubes and end caps. You need to use the supplied thread locker to secure the end cap, or you could buy a set screw for one of the four threaded holes near the end of the tube. The end cap can be used with a FSB and the gas tube well pass through it. You just install the FSB and gas tube after the hand guard and end cap.

I suppose it could be a oz or two lighter but I'm very pleased with the quality and over all look. Topped it off with a set of LMT irons and a PA micro on a AD mount.