How do you crown a cut down barrel?

[JimBrown]

Good evening,
How do I crown a cut down .54 octagon barrel after cut down.
Also who makes .50, .54, and larger crowning tools for muzzleloaders?
Jim Brown
also can e-mail
[email protected]

 

[John Taylor]

There are several ways to crown a barrel. I use a lathe but not every one has access to one. Some take a small ball slightly bigger than the bore and use emery cloth on it to work the sharp edges off but I have not seen one that looks good doing it this way. The whole idea is to take the sharp edge off to keep from tearing patches when loading. First would be to file any saw marks off. Then you might try a small grinding stone that has a 1/4" shaft that will fit in a drill, stone should have a 45 degree angle and be big enough to not go in the bore all the way. You don't need to take very much off, just a little past making the lands smooth with the bore. Now it needs to be polished. Emery cloth on a wooden cone worked by hand will do the trick. Some say a coned muzzle is easier to load but I have never done that to any of my rifles.

 

[MercerLake]

The method that I have used several times is to use the round head of an unplated carriage bolt chucked in an old hand power drill with valve -ginding abrasive. Clamp the barrel in a vise and check for the muzzle face being as square as possible to the flats with a layout square. Plug the bore with a patch on a string, push the patch and string down the bore about a 1/2" or so. You will use the string to remove the patch later when finished. Put a generous amount of grinding compound in the bore to fill the space above the patch/bore plug. Then rotate the bolt head with the hand brace while rotating the brace in arc. This will cut fairly fast and produce a smooth crown. If the tapered area around the bore appears to be larger on one side of the bore this indicates that the barrel is not faced squarely. This can be corrected easily with a flat mill-file by filing until the tapered area is even around the bore. Carriage bolts are cheap, the valve-grinding compound will imbed itself into an unplated bolt more readily than a plated bolt. This process takes only a few minutes and is fairly fool-proof, which is why it works for me! :grin:

 

[spottedpony]

The method that I have used several times is to use the round head of an unplated carriage bolt chucked in an old hand power drill with valve -ginding abrasive. Clamp the barrel in a vise and check for the muzzle face being as square as possible to the flats with a layout square. Plug the bore with a patch on a string, push the patch and string down the bore about a 1/2" or so. You will use the string to remove the patch later when finished. Put a generous amount of grinding compound in the bore to fill the space above the patch/bore plug. Then rotate the bolt head with the hand brace while rotating the brace in arc. This will cut fairly fast and produce a smooth crown. If the tapered area around the bore appears to be larger on one side of the bore this indicates that the barrel is not faced squarely. This can be corrected easily with a flat mill-file by filing until the tapered area is even around the bore. Carriage bolts are cheap, the valve-grinding compound will imbed itself into an unplated bolt more readily than a plated bolt. This process takes only a few minutes and is fairly fool-proof, which is why it works for me! :grin:

An old DIY gun repair book i have, recommends the same method for crowning except suggests a brass carriage bolt.
another thing suggested in this book, is drill a hole through a wood block, 3 inch or so thickness, of the appropriate diameter to clamp snugly around the barrel, cut it in half, and clamp around the barrel, at the muzzle, giving you a flat surface for a file guide to help square up the cut.

 

[paulvallandigham]

Caution: Using that block will square the muzzle to the OUTSIDE of the barrel, but not necessarily to the BORE of the barrel. Most barrels made today, are first bored, and then have the flats ground into the surface, so they are reasonably consistent, and the flats are square to the bore. This method will work with such barrels. However, I would be cautious trying this method on a barrel made in Europe on some of the cheaper guns, or on some old barrels you can still find being sold made here in the USA, when the boring was made to octagon stock. Runout was often a real problem, even as late as the 1980s.

 

[rkeltner]

i always used a machinists square and eyeballed it to get it squared in the first place.(sorry , i'm a machinist by trade, and have trained my eyes well over the years) once squared, i've taken to using a mounted grinding ball about half again bigger than the bore. using only slow speeds and enough oil to keep things slick, i've always gotten a good looking crown, and have frequently improved the accuracy of the rifle!!!!

 

[J.D.]

File the muzzle as flat as possible,using a machinist square to check for "square" as you file. This is a little harder on a tapered or swamped barrel, but it can be done.

The muzzle doesn't have to be perfectly square with the bore, but the closer to square it is helps to form a good crown.

John Taylors method to form the crown is probably the way to go, but I would suggest using a round ball grinding bit. Used with very light pressure and and low speed, and by rotating the ball as you grind, a good crown will be formed in only a few minutes. Polish with with fine grits embedded in a round end of a file handle, or glue fine grits of wet or dry paper to the end of the file handle. Or, back the paper with your thumb. All you need is some way to form a good radius that will allow easy loading.

If you are not satisfied with the crown, follow up with one of Joe Woods's coning tools.
J.D.

 

[Zonie]

While the carrage bolt and ball shaped grinding wheel will create a crown, IMO it's the kind that is good for breech loading guns but not very good for muzzleloaders.

A good muzzleloading crown will be a smooth radius which removes all of the sharp edges where the bore and rifleing meet the face of the muzzle and the best way I've found is to use 180 grit wet/dry silicone carbide sandpaper and my thumb.

By tearing off 1 X 1 inch squares and placing them on the muzzle and then pushing them downward into the bore with the thumb, rotate your hand back and forth while also rotating the barrel.
Try to maintain a constant amount of material removal and change the paper often.
Soon, what was a sharp edge will become rounded off with a fairly nice radius replacing it.

When all traces of sharp edges have been removed, change the paper to a 320 grit, then a 400 grit and finaly a 600 grit repeating the above method.

The 600 grit paper will wear out fairly fast leaving a nice polished surface.

This method takes a bit of time, but using this method my guns have always been very accurate and they never tear a patch from loading.

It also doesn't require any special tools. Just 3 or 4 dollars worth of sandpaper.

zonie