AR Rookie Needs Guidance

Glockster

CGN Regular
Rating - 100%
27   0   0
Okay I want to install a flat top receiver, and a free floating front rail on my Armalite AR15A2 (factory carry handle and hate the high optics mounting), most likely one of the NEA models from Farmboy. Never done any work on the AR platform before. Mostly the Vz series, M305's and bolt guns. So as a DIY project what do I need for tools, and where is the best place to access the tools? I know Brownells, but what about Canadian sources? DVD's a good idea or books. Please advise. Thanks.
 
Tools you'll need:
A decent bench mounted vise. A 5" or 6" model is good.
A set of barrel blocks for the vise.
An upper receiver vise block.
A decent pin punch set.
Barrel nut wrench ( Brownells has both a combo tool and a dedicated spanner that mounts to a 1/2" or 3/8" drive - If you plan on doing any amount of wrenching on ARs, get them both, otherwise the combo tool is OK).
Snap ring pliers.
Brass hammer.
Needle nose pliers (to hold those pins you need to pound back in - I use the small vise grip ones).
Small blocks of wood for propping work while you bash pins - I use bits of 3/4" plywood I've made into jigs, but the Brownells delrin blocks are decent.
Any other tools you'll need for the float tube - most likely Allen wrenches.

Anything less than the above and you are flirting with Mr. Murphy.

You can buy tools alone from Brownells with no fear of the ITAR nonsense, and you will pay less then anywhere else.

There are decent write ups on Brownells and AR15.com.
The only big things that are of concern is a) don't over tighten the barrel, and ensure the gas tube is alligned properly so as not to bind with the carrier key on re- fitment.
 
Assuming you don't want to ruin the carry handle upper when you remove it, you'll unfortunatley need purpose-made receiver blocks.

There are ways to do without when you have a flat-top, not so much with the carry handle versions.

Some other things you'll want:

-grease for the barrel nut threads for the barrel re-install. I like lubriplate, but basic lithium grease, wheel bearing grease, etc. will do.
-blue loctite 242 or similar for your free float tube fixing screw threads
-a set of alignment parallels to align the float tube (assuming it is railed) with the top of your new upper
-an appropriately sized spanner for your muzzle brake. the cutout on the armorer's tool isn't ideal IMHO.
-roll pin punches if you plan to change the upper receiver parts kit over to your new upper (if you get a stripped upper).
 
The Brownells upper receiver block has notches for standard forged A2 and flattop models. Where you will run into problems is with billet uppers.
I personally would not use grease on the barrel nut threads - it cooks off and leaves a mess. A better option is a very, very slight coat of anti-seize, but to be honest, you're barrel should not be tightened on there enough to need it.
 
Moderate abuse? I'm disappointed in hearing that.
You're right though with mag law such that they are, I doubt a good grease would get hot enough to cook off.
I guess old habits do die hard.
 
FWIW, the US DoD technical instructions for the M16 say to use lube on the threads for assembly...

ARMY TM 9-1005-319-23&P AIR FORCE TO 11W3-5-5-42 CAUTION Do not apply pressure to the receiver. REASSEMBLY 1. Position barrel nut (1) by sliding it to the rear of rifle barrel assembly (2) as far as possible 2. Slide handguard slip ring (3) over barrel nut (1). 3. Press slip ring spring (4) from both sides and insert It Into handguard slip ring (3) 4. Install retaining ring (5) against slip ring spring (4) using retaining ring pliers Snap retaining ring (5) to barrel nut (1). NOTE After cleaning, apply molybdenum disulfide grease to threads of barrel nut assembly before Installation.

But probably the DoD is wrong. Just skip the lube because people on the internet are telling you to - that's as good a reason as any.
 
Just a point on tools. Buy good stuff. Don't skimp on tools. Here's a few recommendations:

SEI USMC AR M16 Barrel Wrench - Best on the market, hands down. Other brands (bushmaster, NC Star etc) don't hold up and eventually slip.
USMCBarrelWrench-1.jpg


Spike's M4 Stock Wrench - Another great "must have" tool. Pure quality.
SpikesStockWrench-1.jpg


Delrin Action Block (DPMS) - Better then the plastic Brownell's one. Works with any and all receivers and rail systems, unlike the clam shell designed ones. Spike's makes a really nice Aluminum one as well, but it's a little more money.
DPMSActionBlock-1.jpg


Check out this series of posts on ARF.com, it covers AR15 Assembly:

http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782
 
Last edited:
Delrin Action Block (DPMS) - Better then the plastic Brownell's one. Works with any and all receivers and rail systems, unlike the clam shell designed ones. Spike's makes a really nice Aluminum one as well, but it's a little more money.

I wouldn't use the DPMS action block to install a barrel. I doubt it would take the torque of the barrel nut. I think it was only designed to assemble the uppers receiver. ie forward assist, ejection port cover
 
Last edited:
FWIW, the US DoD technical instructions for the M16 say to use lube on the threads for assembly...

But probably the DoD is wrong. Just skip the lube because people on the internet are telling you to - that's as good a reason as any.

:rolleyes:The point I was making is that you need very little if any. If you peel your nose away from pamphlets and manuals you might understand the use of a lube is to prevent galling and potential stripping of the threads on the aluminum receiver. The barrel does not need a lot of torque...in a lot of cases much less than the spec'd.
Don't take my word for it...gain some knowledge by wrenching and shooting them for a few decades.:HR:
 
Delrin Action Block (DPMS) - Better then the plastic Brownell's one. Works with any and all receivers and rail systems, unlike the clam shell designed ones. Spike's makes a really nice Aluminum one as well, but it's a little more money.

I wouldn't use the DPMS action block to install a barrel. I doubt it would take the torque of the barrel nut. I think it was only designed to assemble the uppers receiver. ie forward assist, ejection port cover

It takes barrel nut installs fine. I torqued one to 65 and it didn't budge. Maybe if you were doing 10 barrels a day I would use a receiver block.
**gun techs and armorers use them all the time for barrel work
 
It takes barrel nut installs fine. I torqued one to 65 and it didn't budge. Maybe if you were doing 10 barrels a day I would use a receiver block.

It isn't the block you should be worried about, but the upper receiver. 65 ft/lbs is a lot on the receiver, especially if it isn't supported. The clamshell and the Insert are designed to support the receiver walls from becoming distorted from the torque being applied to the barrel.
 
True, the clamshell would offer more support.
using the minimum 35 foot pounds to finish a barrel nut with alignment is rare, getting the next hole to line up usually pushes it up to 55-65.
80 is the max foot pounds in the AR15/M16 manual.

Some US armourers have put 100 foot pounds on them with no disasters. (deployed weapons). I cringe at that.....

The DPMS claw offers inside support but having the clamshell is double the support (inside and out). I suggest getting both ;)
 
Back
Top Bottom