Muzzleloader barrel crowning?

[Lastmohecken]

I have seen pictures on here, if I remember right, and also original rifles at gunshows, with really strange crowns on them. They usually are quite rough and look almost like a star, which was filed out, leaving a very rough groove, it seems, leading out from each groove in the rifling.

How can these be accurate? But it must be fairly common, can someone explain this practice to me? History, and did they really shoot? Just curious, as it seems like if they really are accurate, then it would seem like any kind of barrel crown would be about as good as the next.

[Three Hawks]

Years ago the NRA did a series of tests of muzzle crowns starting with barrels simply cut off by hand with a hacksaw, then that barrel deburred only with a pocket knife to the same barrel trued in a lathe and deburred only, then having a mil. spec. crown on it, then having the barrel cut and deburred at five degree increments.

All cuts were tested at 100 yards from a machine rest  ten shots. It wasn't until the cut off barrel got to about 20 degrees that accuracy suffered measurably.   The rifle used  was a Springfield M-1903 fitted with a Remington 2-Groove barrel.  

Anyway since I read that article, I quit worrying about crowning barrels I cut off.  I square the cut end with a machinist's square and a file, then deburr the bore with a sharp 82 deg. countersink, and go on with my life.   Since I'm not competing in 300 yd bench matches where a difference of group size of .001 will win or lose I figure that minute of soda cracker or NECCO wafer will do me just fine.

I too, have seen many muzzleloader barrels with decorative muzzles and crowns.  I like 'em but I'm too lazy to do one.

If you need a perfect crown take a round  brass screw or bolt head bigger than the bore you're crowning, apply valve grinding paste to the head and turn it at moderate speed in the bore of the cut muzzle until the edge of the muzzle has been visibly polished all the way around.  Since a sphere which contacts a cylinder evenly all the way around means that cylinder edge is exactly square to the centerline, you'll have  perfect crown whether or not the muzzle is cut perfectly square to the centerline of the bore.   Then you can clean up the cut surface of the muzzle and call it good.

I just eyeball it and call it good, never had a problem either.    

Not anal retentive ol'

Three Hawks