Cut and Crown with handtools ??? Long

HankL · January 8, 2001, 07:22 PM

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

James K · January 8, 2001, 11:05 PM

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

HankL · January 9, 2001, 07:45 PM

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.

James K · January 9, 2001, 08:45 PM

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

HankL · January 9, 2001, 09:12 PM

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

I'll let you know that you had the right idea later!

beemerb · January 10, 2001, 07:17 PM

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.

HankL · January 10, 2001, 07:44 PM

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

radom · January 12, 2001, 04:30 PM

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.

HankL · January 20, 2001, 07:34 PM

The Tools:

The Crown:

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.

DeBee · January 20, 2001, 11:52 PM

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...

HankL · February 4, 2001, 03:17 PM

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.

Jordan · February 6, 2001, 01:11 PM

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!

HankL · February 6, 2001, 07:55 PM

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

January 20, 2001, 07:34 PM	#9
HankL Senior Member Join Date: March 11, 1999 Location: The Sunny South Posts: 2,174	I had to give it a try The Tools: The Crown: 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. Last edited by HankL; June 25, 2001 at 07:07 PM.

February 4, 2001, 03:17 PM	#11
HankL Senior Member Join Date: March 11, 1999 Location: The Sunny South Posts: 2,174	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. __________________ Check 6

January 8, 2001, 07:22 PM	#1
HankL Senior Member Join Date: March 11, 1999 Location: The Sunny South Posts: 2,174	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

January 8, 2001, 11:05 PM	#2
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	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

January 9, 2001, 07:45 PM	#3
HankL Senior Member Join Date: March 11, 1999 Location: The Sunny South Posts: 2,174	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.

January 9, 2001, 08:45 PM	#4
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	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

January 9, 2001, 09:12 PM	#5
HankL Senior Member Join Date: March 11, 1999 Location: The Sunny South Posts: 2,174	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 I'll let you know that you had the right idea later!

January 10, 2001, 07:17 PM	#6
beemerb Junior member Join Date: October 2, 1999 Location: AZ Posts: 1,759	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.

January 10, 2001, 07:44 PM	#7
HankL Senior Member Join Date: March 11, 1999 Location: The Sunny South Posts: 2,174	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

January 12, 2001, 04:30 PM	#8
radom Senior Member Join Date: January 21, 2000 Posts: 1,357	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.

January 20, 2001, 11:52 PM	#10
DeBee Senior Member Join Date: October 5, 1999 Posts: 408	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...

February 6, 2001, 01:11 PM	#12
Jordan Senior Member Join Date: February 25, 1999 Location: crow pass trail head, Eagle River, AK Posts: 228	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!

February 6, 2001, 07:55 PM	#13
HankL Senior Member Join Date: March 11, 1999 Location: The Sunny South Posts: 2,174	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