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 How can I counterbore a rifle?
kingfish  [Member]
11/1/2010 2:22:17 PM EST
I have one of those old yugo guns with a seriously shot out muzzle that swallows a bullet. Is there a way that I can counterbore it in a manner similar to that of the M44 that the russians did?
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LazyAndy  [Member]
11/1/2010 3:38:13 PM EST
Certainly. Counterboring is simply drilling out the barrel from the muzzle end until you reach good rifling. However, that is easier said than done. You would need some type of pilot to make sure you are keeping it concentric to the bore as you are drilling. Unless you are mechanically inclined, I do not think this is a job that should be attempted by the average person with a black and decker walmart drill. How far away is the nearest good rifling from the muzzle?
Milo5  [Member]
11/1/2010 5:29:05 PM EST
Three ways to do it.
1. Chuck the barrel in a lathe and use an end mill to counterbore muzzle.

2. Clamb barrel up through hole in a Bridgeport floor mill table and counterbore using the end mill.

3. clamp barrel in through hole of a floor drill press and use end mill to counterbore.

1/2" end mill should be sufficient, use lots of cutting oil and high speed/moderate feed.
cosmo05  [Team Member]
11/5/2010 12:33:16 AM EST
Originally Posted By Milo5:
Three ways to do it.
1. Chuck the barrel in a lathe and use an end mill to counterbore muzzle.

2. Clamb barrel up through hole in a Bridgeport floor mill table and counterbore using the end mill.

3. clamp barrel in through hole of a floor drill press and use end mill to counterbore.

1/2" end mill should be sufficient, use lots of cutting oil and high speed/moderate feed.


Just leave the square cut inside?

Milo5  [Member]
11/5/2010 3:57:00 AM EST
Burnish the cut if you like.
Remember to plug the barrel before making the cut.
If you want a more rounded cut at the bottom of the counterbore, use a bullnose end mill.
kingfish  [Member]
11/9/2010 7:50:36 AM EST
I dont have any of that stuff guys.
What I have is a crown cutter that has a 30 cal brass pilot. That obviously wont counterbore, but something just like it but with a narrower crown cutter (say .4" wide cutter with a 30 cal bore guide) might work
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