Gunsmithing Removing Barrel from AR, and free float questions

[Jester8]

First off rifle is a DPMS A3, 16" barrel, glacier handguards. I bought a FA Enterprises free float tube, and the DPMS action block. Got my ft lb torque wrench, and my AR wrench.

Now down to the question(s):


How much force is needed to loosen the barrel nut?


Do I need to put anything in the upper reciever to keep from twisting, besides the action block, if I do please elaborate?


Is there a specific torque setting that is condusive to better accuracy?


Thanks for the help

 

[nicholst55]

Re: Removing Barrel from AR, and free float questions

The action block <span style="font-style: italic">should</span> have an insert that replaces the bolt carrier to support the upper, seen here: http://tinyurl.com/yzp7khy. The barrel nut <span style="font-style: italic">should</span> be torqued to a minimum of 30 Ft-Lbs from the factory. IME, some ARs shoot better with the most torque you can use and still align the barrel nut with the gas tube hole in the upper. The problem is that the Armorer's wrench usually starts slipping and stripping teeth off the barrel nut once you get much past 30 Ft-Lbs.

I usually just use, and recommend, torquing to 30 Ft-Lbs for this reason. You really should apply a moly grease to the barrel nut threads, and torque the nut three (3) times like the TM says to, to insure proper seating. Don't use a grease that contains graphite, as it can cause severe corrosion of aluminum - just a moly grease. You can buy the grease at most any auto parts store.

 

[ARsR4ME]

Re: Removing Barrel from AR, and free float questions

I've been down the road of broken teeth on the barrel nut before when tighting and looseing. If all else fails you can use a pipe wrench but be very very careful not to break things. I've had to use it to align the gase tube holes before and remove some stuck nuts but please be careful.

 

[kilo7788]

Re: Removing Barrel from AR, and free float questions

Army and Air Force Manuals say min of 30 max of 80. Ensure you use proper tightening technique with lube. (tighten to tq then loosen then tighten then loosen then tighten) Not jerking you chain that is proper procedure confirmed to me by Chris Bartocci from Colt(autho of the black rifle II).

 

[Jester8]

Re: Removing Barrel from AR, and free float questions

I was going to order that block from Brownells but it was out of stock, so I ordered the DPMS one where the upper reciever actually pins into the block. I think that it actually goes far enough into the upper to not allow twisting. It will be here tomorrow, so I will have to check it out.


Will bolt lug grease work?

 

[frog5215]

Re: Removing Barrel from AR, and free float questions

Grease, tighten and loosen x3, torque on the 3rd time, >30LB, <80lb, to align gas tube.

 

[kilo7788]

Re: Removing Barrel from AR, and free float questions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: frog5215</div><div class="ubbcode-body">Grease, tighten and loosen x3, torque on the 3rd time, >30LB, <80lb, to align gas tube. </div></div>
What I said alot simpler.

 

[kilo7788]

Re: Removing Barrel from AR, and free float questions

It doesn't really matter what you use. The lubrication is to prevent getting a false reading of torque from the wrong friction. tightening and loosening 3x is to ensure there are no metal snags and ensure everything is smooth and in proper contact.

 

[Jester8]

Re: Removing Barrel from AR, and free float questions

Ok, thank you guys

 

[Johnsusername]

Re: Removing Barrel from AR, and free float questions

Hi,
Place a bucket under the action block.
Pour a cup of hot water onto the threads of the upper and barrel nut.
Loosen with the wrench.

The aluminum will expand at a faster rate than the steel barrel.


John

 

[LoneWolfUSMC]

Re: Removing Barrel from AR, and free float questions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jester8</div><div class="ubbcode-body">I ordered the DPMS one where the upper reciever actually pins into the block. </div></div>

That is the one I have. It works fine.

 

[Jester8]

Re: Removing Barrel from AR, and free float questions

Got it off no problem, one little turn and that's all she needed. Thanks for the help guys.

 

[ARsR4ME]

Re: Removing Barrel from AR, and free float questions

Glad to hear it. Any pics of the new free float installed?

 

[Jester8]

Re: Removing Barrel from AR, and free float questions

Waiting for it to come it, was suppose to ship Monday, but now it's on backorder. I'll take some pics when I get everything together.