The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > The Smithy

Reply
 
Thread Tools
Old September 25, 2006, 03:40 PM   #1
westphoenix
Senior Member
 
Join Date: November 15, 2002
Location: Phoenix, Arizona
Posts: 582
Crowning for cheap....... Yugo SKS

I have a Yugo SKS I am modifing.
We don't need to get into the legal issues of this.
I am just looking for help on muzzle crowning.
My first idea was to remove the barrel and turn it on a lathe.
But there is a lot of pins that are pretty suborn and I decided to do it by hand or with a hand drill attachment.
I would like to keep the tool cost under $50 if possible.

I have already cut the barrel.
I'm going to do some filing to get the muzzle straight.
The 11 degree counter bore cut seems popular.
Which I am considering.
But what other options do I have?
Where to buy the tooling (remember I want to keep it cheap, I will probably only use the tool once)?
Is it best to do this by hand or with a drill?

Would I be better off (cost wise) taking it to a local gunsmith to have the crown cut?
What is the estimated cost of this?

Thanks,

EDIT:
I also heard of using a brass screw, thoughts? expierences?

Last edited by westphoenix; September 25, 2006 at 04:14 PM.
westphoenix is offline  
Old September 25, 2006, 04:26 PM   #2
sleeping dog
Senior Member
 
Join Date: March 2, 2000
Location: MI
Posts: 536
I did it to one rifle, cut the barrel from 26" to 22". I used a grinder to get it as square as I could. Then a ball-shaped stone, 1/2" dia, to grind an indentation at the muzzle. Then a brass screw in a drill with valve-grinding compound to polish it.

It shoots great. A "real" muzzle tool would probably have done a nicer job and done it faster, but this worked.

Quote:
We don't need to get into the legal issues of this.
If you think you have legal issues, don't even think about taking it to a gunsmith. He doesn't need the aggravation. If he thinks he has to choose between his license and your ass, then adios ass.

Regards.
sleeping dog is offline  
Old September 25, 2006, 04:48 PM   #3
westphoenix
Senior Member
 
Join Date: November 15, 2002
Location: Phoenix, Arizona
Posts: 582
No I know what I am doing is legal, I just didn't want the conversation to turn into what I need to do to the Yugo to be legal. I want to keep it on the muzzle crown issue.
westphoenix is offline  
Old September 25, 2006, 07:51 PM   #4
Unclenick
Staff
 
Join Date: March 4, 2005
Location: Ohio
Posts: 10,221
I prefer lapping a crown. See my first reply post in this thread for a description. Not a free lunch in terms of bother, but not a big expense, either. The main thing is the muzzle needs to start out truly squared with respect to the bore for it to work accurately, and that means doing more than just eyeballing it.

Since the Brownells tool that squares a muzzle is outside your budget, you can take a 1/4" brass rod that goes all the way down the barrel and buy a bronze shoulder bushing that slips over it, shoulder against the muzzle, and use that and Magic Marker or match smoke or high spot blue to see where the shoulder rubs? This tells you where to scrape or file. If the rod is all the way through the barrel, its error angle will be pretty small, but you can use tape to bring the fit still closer. The object is to get the bushing shoulder to touch evenly all around the muzzle for as far out as the edge of the crown is to go.

Don’t get too worked up about muzzle crown angle. Harold Vaughn tried a bunch of different ones, and as long as they were symmetrical about the bore axis, it didn’t make any difference to accuracy what angle they were. As an aerodynamicist, he suspects the 11 degree number comes from a mistaken notion that because an 11 degree angle is the greatest departure a bullet’s boattail can make without incurring more than laminar flow drag against its sides, that this angle would somehow be helpful to bullet exit ballistics. Just pick something that recesses far enough so the edge of the bore is protected from minor bumps and dings. That’s the purpose of a crown, anyway. Otherwise, the square cut would be king.

Nick
__________________
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Benefactor Member
Unclenick is offline  
Old September 25, 2006, 10:15 PM   #5
T. O'Heir
Senior Member
 
Join Date: February 13, 2002
Location: Canada
Posts: 3,193
Getting a flat surface with a file takes a great deal of skill. Proper crowning tools run $600 from Brownell's. Take it to a smithy.
T. O'Heir is offline  
Old September 26, 2006, 03:03 PM   #6
dfaugh
Senior Member
 
Join Date: January 17, 2002
Location: Upstate NY
Posts: 1,715
Quote:
Getting a flat surface with a file takes a great deal of skill. Proper crowning tools run $600 from Brownell's. Take it to a smithy.
SAY WHAT? I bought my crowning tools from Brownells. The initial cost (I bought a "squaring cutter" and an 11 degree crowning cutter), then you just buy the pilots for the appropraite caliber. As I recall, it cost me about $120 for the initial setup (the 2 main tools, and one pilot). But, additional pilots (I now have half a dozen) only cost a few dollars. So, if you even THINK you might want to do another gun in the future its worth it to get the right tools.

I've seen all sorts of "home grown" methods for doing re-crowning, and after many years of metalworking (some work, some play) I find it REAL dubious that anyone can get REALLY good results, without the proper tools. Might work, more or less OK, but not gonna give the best possible accuracy.
__________________
"If you Listen to Fools, the Mob Rules"

"No one has the answer, but one thing is true.
You'e got to turn on evil, when its coming after you.
You've gotta face it down,and when it tries to hide,
you've got to go in after it, and never be denied.
Time is running out...Let's roll.
Let's roll for freedom, let's roll for love.
We're going after satan, on the wings of a dove.
Let's roll for freedom, let's roll for truth.
Let's not let our children grow up fearful in their youth."
dfaugh is offline  
Old September 26, 2006, 05:05 PM   #7
westphoenix
Senior Member
 
Join Date: November 15, 2002
Location: Phoenix, Arizona
Posts: 582
This is my first time doing this and need to do it for cheap.

Let me make sure I understand this:
I should be using a squaring tool, this tool will have a pilot that is inserted into the barrel and the cutter will cut the muzzle square with the bore.
Then I should using a crowning tool, to cut the crown. The crowning tool will also have a pilot that is inserted into the barrel to center the crown.

I may need to do this to another SKS in a few months to a year.
If I decided to spend a few extra bucks now (keep it under $100) what tools should I buy? Remember this will probably be used once or twice.

I wish I could rent these tools.
westphoenix is offline  
Old September 27, 2006, 12:53 PM   #8
8milimeter
Member
 
Join Date: January 3, 2005
Posts: 41
re-crown

I have used this technique on several rifles with great results. If you take your time you can make it look like a factory job.

http://www272.pair.com/stevewag/muzzle/mz.html
8milimeter is offline  
Old September 28, 2006, 12:34 PM   #9
westphoenix
Senior Member
 
Join Date: November 15, 2002
Location: Phoenix, Arizona
Posts: 582
8mili thats actually what I planned to try.
Ill let you guys know how it comes out.
westphoenix is offline  
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:01 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2014 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.08040 seconds with 9 queries