finally got ofRiver Ar my butt and did it

ok , have the Bushmaster DCM , and then fell into a Colt Match Target HBAR , the HBAR was lacking some of the improvements that the DCM was sporting most notably the A2 Free Float system , so purchased it from Rock River Armory , the plan is to dress both out equally with the same "addons" , leaving the basic rifle as is to see which is the better rifle

my process is to move the project to the bench and think about how/what i need to do to get it done , usually starts with dipping my toe in something easy , for instance the K98 Faux sniper project is in this stage i started lapping the high turret mounts to the receiver and receiver bridge

got off work early on a friday like 3 or 4 weeks ago and said today is the day and jumped in , on getting the FF system done on the Colt , that turned out to be a bad day , barrel nut refused to budge , i was using a Wheeler armorer tool and the 3 pin was the only one that matched the B Nut , snapped a pin on the wrench trying to get it off , after a tyrade of cursing that im sure was bad enough to open a portal to hell , i ordered a Real Avid (awsome choice BTW)

while waiting for that to arrive i declared the barrel nut boogered due to when the wrench snapped it boogerd a couple teeth on the nut , so i slapped a cut wheel on the dremel , cut the D ring off , and then scored the nut in 2 places half way through being very cautious not to go all the way through because thats the receiver threads , slapped a pipe wrench on and with very little pressure it broke free and spun right off

scoring the nut like that allows the two halves you are creating to "flex" in turn breaking the grip it has on the threads without the un necesarry stress on the receiver , Colt applied ZERO nut butter on the threads , they did use nut butter on the barrel shank , no wonder the barrel nut refused to budge , no nut butter and possible torque on the high end of parameter

had a spare barrel nut and D riing assemble , wrench arrived and all else went according to plan

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if you are wondering about the sling swivels , they are no longer attached to the front sight tree , you must cut that one off in order to be able to return the front sight tree back in place , the new swivel is mounted to the Free float tube , i dremeled it off and used a sharp fine file and worked it flush , then sprayed some Alumihyde II epoxy resin gun kote into a bottle cap and painted it with a artist brush

as for the new swivel , what i do with those is i have a piece of 3/4 flat stock i use as a anvil , place a thin rag over it and position the rivet on the anvil , i start with a punch that has a conical point that is about 2-3 times larger than the rivet , and start tapping the hole side of the rivet keeping the punch straight as to spread the rivet evenly, whne i get about half way i then swtch to a flat punch and start to flatten being mindful to stop just before flush with the swivel base

I built a couple match AR's last year, an A4 and an A2. The trick is to use a dab of nickel anti-sieze on the barrel nut threads. Likely the last person to attach your barrel must have forgotten that step. If you didn't do it, go back and do it again. If you shoot a lot and think there will be a likelihood of a barrel change in the next couple decades, you'll thank yourself.
I have that wheeler wrench and I'm not a fan. The one I use all the time is from a guy on eBay that makes them, but I don't think he's selling them anymore. I did have to open it up a bit since the OD of the free float tube is larger than a standard barrel nut.

here is the grease i use , on both the barrel shank and the threads , ive popped the barrel of one or two after using this stuff , easy peasy , the barrel on the colt is a Colt marked barrel , so either its the original barrel or was replaced with a Colt Barrel , my guess is Colt never nut buttered the threads , here is a pic of the Real Avis wrench , the pins are molded with the wrench , no way it will sheer , but next time i get a problem child like this Colt was i will jut cut the D ring and score the nut like i did here , i have extras from takeoffs when replacing handguards with proprietary barrel nuts

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Unbrella Corp , i call it zombie grease , if you are a gamer you will know what i mean,lol

I also start my torque wrench at [TM 05538/10012-IN], back the nut off, increase to [TM 05538/10012-IN], back off... and so on until I achieve alignment with less than 80 ft.lbs. The principle is to ease in to set the softer aluminum threads into the steel ones without any damage or galling.

torque specs are 30-80 ft lbs , i set it to 35 and do the tighten loosen 3 times to marry the threads if you are starting at 50 that doesnt exactly give you a ample window to align the nut

Quote:

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Originally Posted by micmacman

do the tighten loosen 3 times to marry the threads

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That's what the books on this describe. Third time you line up the castellation nut to the gas tube notch.

I shall correct myself, and I should have looked it up before I typed, but I guess my foot tasted pretty good at the moment :). I will delete/modify my previous post to not be incorrect (sorry too, grammar police, for the double negative).
If you are watching your nut as you sneak up to snug, the torque spec isn't the most important part (except for the "do not exceed 80 ft.lbs"). The nut will align exactly once in the specified range.

USMC Maintenance manual TM 05538/10012-IN

Again, the important part is "not to exceed 80 ft*lbs". It also says to start at 30 to work the threads as we have mentioned. I've never seen one align at 30, and in my experience alignment usual happens after 50. But again, the number doesn't matter. The instructions in the manual are "Marine proof" because in practice, once you see alignment in the window, you will not see alignment again unless you go over 80, so the double caution in big bold letters in the manual is meant to say don't bother trying.

i agree , never had one align anywhere near 30 , and no need to apologize , i was more worried that was misinformed about the torque specs , and i could careless about grammar , im a hillbilly indian so i was doomed at birth as far as grammar goes and we're in a forum chat ,not writing the great american novel ,lol