View Full Version : Muzzle Crowning
muzzlepatch
01-26-2007, 19:18
My new Glock 19 is a disappointment when it comes to shot grouping. A close inspection of the muzzle shows what I believe to be a rather roughly finished crown. This is of course a factory barrel; and only FJM has been fired through this gun. I of course didn't purchase this gun for a target pistol, but its grouping simply pales in comparison to everything else I own. I've achieved better groups with a snubby, quite frankly.
I'm certainly competent enough with general gunsmithing, but crowning is a machining process, and I might be better off having an pro do it for me.
Suggestions, my dear armorers?
you can do it yourself if you have some mechanical ability and a drill press or equivalent
get a 40 or 45 cal ball bullet and some valve polishing compound from auto store [want fine grit not coarse]
set the barrel up in a padded vise on the drill press table so that the barrel is vertical and centered on the press axis mount the bullet in the chuck with the ball profile down and align the barrel with the chucked bullet apply some compound to the bullet and set press to medium speed lightly lower the coated bullet into the muzzle to polish the crown do small passes and use only very light pressure - add compound often and check crown often
it isn't hard but takes some equipment and patience
A 1-1/2" or 2" round head brass screw works great. Get one large enough for your 0.355" barrel. Probably one with a head width of around 1/2" or larger. I've never looked for one that large but they're probably available in the specialty fastener drawers at your local hardware or home store.
For my Garand and old 10/22 I chucked the appropriate sized screw in a cordless drill, slopped on a bit of JB Bore Bright and worked it arond in a random/ circular motion for a minute or so. Continued until I got what I wanted.
If you haven't shot it in a ransom rest or had several experienced Glock shooters try, don't assume it's the barrel.
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