Filed muzzle crown

[D. Taylor Sapergia]

For some time I have been anxious to file out the grooves on the crown of my rifles, but I've been too much os a chicken to take the chance on destroying the accuracy.  I took the leap. 
Don Getz said to me that the ball must exit the same muzzle every time, and every time does it the same way.  So how could it effect accuracy?  I just took a round needle file and went at it, filing as evenly as I could by eye, the round bottomed grooves in an already perfect crown.  I haven't shot it at paper off the bench yet, but all shooting thus far is just fine.  I won second place in the Alberta Bullseye shoot at Heffley this year with the rifle, and I have yet to do as well with a rifle in that match, so something must be working.  Here's the before and after...the rifle brand new, and now.

[Leatherbelly]

Hey Taylor,
 That's real nice! Now go ahead and put the "V" notches on the lands!

[bob in the woods]

That looks really good to me. I tried one, but filed the lands with a small round file. Looks like yours, but different, sort of. Don't ask me why..I read something in either Muzzleblasts or Muzzleloader about doing it that way. The barrel still shot ok, so I guess it worked. Sure made it easier to load.

[hanshi]

I wouldn't want to trust myself with a file, just too shaky.  I have two rifles that need a better crown; would sandpaper (coarse followed by fine) work well enough?  I'd thought about wrapping the paper around a wood or rubber cone or ball for uniformity.  Think this would work?

[D. Taylor Sapergia]

To make a standard styled crown, I usually just use some 180 grit abrasive cloth about 1 1/4" wide, and push it with my thumb into the bore.  Then I rotate the rifle back and forth about fifteen times. 
Then rotate the rifle 180 degrees and do it again.  This puts a rounded even crown on the barrel that does not cut the patch when loading tight combos and makes starting easy.  I finish it with some 320 wet/dry paper on my thumb the same way.
But the original crown as in the first picture was the barrel as it was received from Barbie, and I assume the way Rice sent it out.

[Daryl]

Here is a crown done the way Tauylor described it, uisng your thumb- in this case, my thumb. This is the way I do all crowns, even when using a lathe, after cutting the shallow bevel, like shown in Tayor's first picture.  This crown, newly machined, is too sharp on the corners of the lands and grooves and is difficult loading a very tight combination. The crown on my 14 bore as pictured, allows easy loading with a pure lead ball only .006" smaller than the bore and a .030" denim patch.  The rifing is .012' deep, so you see, I have about .020" compression at teh bottom of the grooves. Just in case you think this combination will deform the ball and cause innacuracy, it still puts them into 1 1/2" at 100 meters and 1 1/2" x 3 1/2" at 200 yards.

Note that the corners at the tops of the lands, and bottoms of the grooves are smoothed, ie: with a gentle angle.  I call this a radiused crown.  It allows easy loading with tight combinations, combinations that allow unlimited shooting without having to wipe as well as producing the best accuracy a non-target rifle can provide.  I have the same crown on every one of my rifles, 2 of which use oversized balls (larger than the bore) and a .018" denim to .020 twill patches.

[jamesthomas]

Those are some very good pictures guys. The crown on my rifle takes a rather sharp turn as it hits the rifling, not enough to cut my patches but enough that i can't load a .495 rd with a .18 or .20 patch. I'll be doing what daryl has done to his rifles to my rifle before i go to the range this weekend. then we'll see about those .18 and .20 patches.

[D. Taylor Sapergia]

On my Virginia rifle, I did not change the original crown on the Rice barrel, just as it came from the source.  When I did the filing, I only exaggerated the grooves with a round file.  I loaded .023" patches before the filing and still use them.  They load even easier now.  And to my great delight, the filing did not alter the rifle's inherent accuracy.

[longcruise]

I wouldn't want to trust myself with a file, just too shaky.  I have two rifles that need a better crown; would sandpaper (coarse followed by fine) work well enough?  I'd thought about wrapping the paper around a wood or rubber cone or ball for uniformity.  Think this would work?

Hanshi, I have done it that way with good success.  OTOH, what Taylor and Daryl do would seem to give the same results and not involve making tools, etc.  My finished crowns look near identical to the one Daryl shows.

Daryl, please send your thumb so I can give it a try.

[Daryl]

HA! - any old thumb will work, as long as it's just like mine - rounded on the end which is what goes straight into the bore, 7/8" wide at the nuckles  and 2 1/2" long.

[hanshi]

I would suppose that as long as you rotate the rifle every 15 thumb rubs it should produce a very uniform crown.  I have sandpaper ranging from very, very fine to fairly coarse and some very fine steel wool.  What success could I expect using these on-hand materials?

[Daryl]

I'd try the fine paper first - like you say, rotate often and the 'concentricity' will be perfect - can't be otherwise.  If it is cutting too slowly, try something a big more coarse. I like to finish with red crocus cloth(emery). It is listed as being 800grit, but seems finer than that.  Crocus, on a tapered soft wooden plug, driven by an electric drill, will comress to the shape of the throat you've 'sanded in' and will polish it perfectly.  I rotate the electric drill ina a mild oscilating pattern.

[hanshi]

I'll show the extent of my ignorance, now.  What exactly is crocus cloth?  I've heard of it before but never seen it as far as I know.  What do you look for when you go to Lowes to know you have the right stuff?

[Acer Saccharum]

Taylor, if you want the ball to shoot to the right, file a little more crown on the right. If you want it to shoot higher, file a little more off the top of the crown. But the effect will be consistent, shot to shot, as Don Getz sez.

[Randy Hedden]

I'll show the extent of my ignorance, now.  What exactly is crocus cloth?  I've heard of it before but never seen it as far as I know.  What do you look for when you go to Lowes to know you have the right stuff?

Crocus cloth looks like sandpaper, but it is a coated with iron oxide and is very very fine.  It is actually for polishing a finished piece rather than sanding.  I doubt you will find any at Lowes, but you can order it over the net.

Randy Hedden

[Stophel]

Taylor, I've filed a couple of barrels like this...but I ain't got the guns done yet, so I haven't shot them!  I can't imagine that it could possibly hurt anything, so long as it is smoothly done (they don't change from shot to shot).  I have seen so many old guns done this way.  It is almost universal on German rifles.  You have a narrow bevel crown, plus each groove has its own little crown.  

I just filed them with a little fine half round file about the same radius as the grooves.

I've tried it with a square groove barrel...with not so much success.  Doesn't quite work the same way.

[billd]

Like RAndy said, crocus cloth is like very fine sand paper but it's not paper backed. It's cloth backed like emery paper. I've seen it in our local Ace Hardware.

Bill

[Daryl]

I thought any hardware store would have crocus cloth that carries emry cloth. It's just a very fine grit with a red colour and generally dark grey or blue backing.  It's an excellent polish for steel - even carefully used, can be good for revolver barrels.  25 strokes through a S&W .38's 6" bl. rendered it just as or more accurate and no leading in a 2,500 week long round torture test.   

[Daryl]

Taylor, if you want the ball to shoot to the right, file a little more crown on the right. If you want it to shoot higher, file a little more off the top of the crown. But the effect will be consistent, shot to shot, as Don Getz sez.

Acer- filing the muzzle to direct the ball was used in the States mostly on double rifles made there. There are a number of antiques so filed in existance.  however, I believe your directions are poplar opposite to the results obtained by doing this. As the projectile leaves the muzzle, the gas first escapes on the side filed and thus directs the projectile in the opposite direction.  I belive this is the manner of the result.

[roundball]

I loaded .023" patches before the filing and still use them.  They load even easier now.

DTS, given the fairly common threads seen about folks crowning muzzles, its always puzzled me why barrel manufacturers don't take their crowns a little further than they apparently do...if they're already into that step of the manufacturing process, the barrel is already into the crowning process, it wouldn't take but an extra second or two to make the crown larger/deeper, so I can't see where there would be any additional manufacturing costs...any idea why barrels are not crowned to a greater extent than they seem to be?

[Daryl]

Polishing the crown with a bit of emery on a finger while the barrel is still in the lathe would be a 15 second job.  Easy to do, but it's still an extra step for them.  Lack of knowledge might be the only stopper to that job, or them paying for that extra 15 seconds might be the only reason.  I think not enough people complain or - they just don't know any better.  My Goodioen barrel supposedly had a 'perfect' crown, not needing finishing - according to them. They still left sharp edges or corners at each land and groove. It didn't take long to fix it and that's a job I really don't mind doing - it's fast and painless.  I've been doing this for years.