Cut and Crown with handtools ??? Long

H

HankL

New member
I have a pre ban AR-15 barrel that I would like to mate with a post ban lower. You already know my problem is the threaded muzzle. What if I were to clamp the barrel {while assembled to a pre ban lower of course} in my rifle vise and thread a nut to within a hacksaw blades width of the shoulder on the barrel to use as a guide and use a solid hard blade to very carefully cut the threaded portion of the barrel off. I would think that after doing this some lapping and cold blue should make the job complete. Any suggestions would be greatly appreciated.
Thanks, Hank
 
It might be more satisfactory accuracy wise to file off the threads, polish by hand with emery cloth to clean up the area, then cold blue. It will not look as good, but playing with the crown with hand tools can have a less than desireable effect on accuracy.

Jim
 
Thanks for the reply Jim. I had thought about doing it the way you describe but had wanted to make it look a little better. If I can pull off a square cut by the aforementioned method and get the burrs out of the bore shouldn't it work? I can spend some money with Brownell's and get one of their crowning tools if need be.
 
All I can say is that you might luck out and get it right with hand tools. But it is iffy. Actually, you might be better off to sell that pre-ban, since they are much in demand, and buy a post-ban barrel without the threading. Try asking on http://www.ar15.com and see what the folks there think.

One idea mentioned here, which I have never tried, is to chuck a round head machine screw in a drill, put emery paste (valve grinding compound or something similar) on it, and run it onto the muzzle. Other ideas are to run in a large 1/2" drill bit, making a triangular crown.

It seems to me that with hand tools, none of these ideas guarantees a perfectly square point at bullet exit, which is the purpose of the whole thing. If one side of the muzzle is higher than the other, one side of the bullet leaves the barrel first, and the gases escaping past it will tip the bullet in the other direction. This is never consistent and the result is inaccuracy.

Jim
 
Thank you Jim :) I know the theory and I do have a brass lap and some compound. If it doesn't work out I can send it to "Billy the Smith" I don't want to sell the barrel as I have never sold a firearm or any of one's parts as far as I can remember. Thank you for the input! :) He said with hacksaw in hand :D
I'll let you know that you had the right idea later! :(
 
If you are going to do the cut take a pipe cutter and use it to scribe a mark on the barrel.It will give you a sguare line to follow.
 
Bob, I'm thinking that the slot that I leave between the step on the barrel and the nut I thread onto it should be square. I haven't done the deal yet, still considering Jim's input. I really don't want to show up at my favorite gunsmith's shop with one of those???
Thanks
 
Replace the brake with a screw on non-military replacement and have it silver soldered on (high Temp solder). The GI issue brake could be welded on but it would need some work on the slots and diameter to make it legal to solder on. Cutting a chrome lined barrel can lead to a chrome flaking problem or so I have heard.:)
 
I had to give it a try

The Tools:
View

The Crown:
View

The only thing left to do is take it to the range. :)
Even if it doesn't work out as planned it was a fun project.

Editied due to loss of server. :p
 
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Wilson's makes a good looking post ban compliant muzzle brake for 80 bucks permantly installed on your threads finished to match.

After ordering the tools from Brownells and doing all the filing and bluing and running the risk of buggering up the chrome lining you're probably better off sending the upper to them...
 
Everything turned out fine! After sighting in, the little AR turned in a 100 yd. 5 shot group of .441 vertical x .543 horizontal measured from outside to outside. Not too bad considering that I was the nut behind the buttplate :)

I did drop some money at Brownells but I still have the tools to do this again if need be. It's always fun for an old dog to learn a new trick as well.
 
You're my hero Hank! I always thought that self-sufficiency was a hallmark of gun owners. I can't believe what jobs some people will helplessly hand over to a gunsmith (or plumber, or mechanic, or etc).

Great job with that barrel!
 
Thank you Jordan but I would suggest that you speak with some folks who know me before letting me be your hero. I am the plant manager of a company and some of our equipment is old and very cranky. Sometimes you just have to figure it out. I can plumb and steam fit with the best of them but once steam or water has been through the line I call the pros fast. Hank & Old Plumbing don't mix at all. The only thing that had me a bit worried was the chromed bore but I figured by slowly facing back the muzzle after the hack saw job and using plenty of cutting oil during each step that I would be fine. I also figured that I could afford the price of a new barrel if need be at the getgo :)
 
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