Question about a lightweight build

[AR-10]

Hey guys, I have a question about a build I am considering.

A guy I shoot with wants to trade a complete Colt 6520 for one of my handguns.

The reason why I am interested - I want to take that barrel, cut it down to 14.5" and pin a Vortex to it. When it all goes back together, I'm going to replace the A2 upper with a flat-top.

So my question is, can a 6520 barrel be cut down and re-threaded or is the profile too small behind the already existing threads?

Please advise, thanks in advance.

[rob_s]

Most skinny barrels like the 6520 bell out slightly at the end just before the threads to provide enough shoulder for the crush washer and flash hider. It's not that you *can't* cut it but I wouldn't.

Check into the Daniel Defense 14.5" lightweight barrels. I have one coming soon. BCM is also rumored to be doing lightweights soon.

[HeavyDuty]

I was under that impression too, Rob - until I saw closeup pics of a BM Superlight that ADCO cut to 14.7 and pinned. The crush washer was the perfect size to provide the missing taper.

I asked ADCO directly about it and was told that cutting and threading a .565-.570 barrel left plenty of meat for timing a muzzle device using a crush washer.

I'm planning on having my A1's Superlight cut and pinned after my DD pencil upper is up and running - the barrel is in transit back to me right now after pinning.

AR-10, I agree with Rob - you might do better to build what you want rather than modify the Colt. The DD 14.5" pencils look to be superb, I can't wait to get mine out shooting!

[Quib]

Randall at AR15 barrels does this type of work. I’m not sure though of his current work load, it’s been awhile since I’ve seen him surface on any of the boards.


Barrel Threading with a step-up bushing added $75
This is done like normal barrel threading with a couple exceptions. Lightweight barrels will usually measure about 0.6" at the muzzle. When I turn that down to 1/2" for 1/2-28 threads, it only leaves a 0.05" shoulder. This is too small to properly torque a muzzle device against as most flash hiders have a generous chamfer at the entry of their threads, this chamfer ends up right against the square corner of the lightweight barrel's shoulder and it's not a good situation. This service includes threading the muzzle an extra 1/4" back and making a threaded tapered bushing that will seat against the small barrel shoulder and provide a more proper shoulder to tighten against. The bushing and threads will be finished with touchup bluing.

http://ar15barrels.com/services.shtml

[AR-10]

Good info, and it is appreciated.

I did not know about DD or BCM's lightweight barrels.

Good to see you QUIB, I remember you from another forum that I used to read.

[Quib]

Good to see you QUIB, I remember you from another forum that I used to read.


Welcome to Weapon Evolution. [:)]

[AR15barrels]

Randall at AR15 barrels does this type of work. I’m not sure though of his current work load, it’s been awhile since I’ve seen him surface on any of the boards.

http://ar15barrels.com/services.shtml

I'm alive and well.
I'm still doing service work, but I got out of making barrels from scratch.
I'm shooting a lot more now that I don't take on so much work.

[Quib]

Good to hear from you Randall!

[Stickman]

Good to see you QUIB, I remember you from another forum that I used to read.



Quib is an asset to any board he is on.

[Quib]

Quib is an asset to any board he is on.


Thank you Sir.