View Full Version : No Lathe Muzzle Crowning

Ace of Spades
November 3, 2005, 10:04 AM
I was thinking about dressing up a few barrel crowns on some milsurps and adding a crown to a NAA Guardian.

I would like opinions as to if this is worth it and what tools are best. I've heard that the Manson cutter is best, but ~$400 makes that mostly unfeasible. Brownell's sells a piloted hand-cutter tool and Power Custom has brass laps that fit in a hand drill, both of which seem more within my budget constraints.

November 3, 2005, 12:50 PM
The Brownell's piloted tool is the best buy, and does a great job.

When using it, be sure to position the barrel with the muzzle DOWN.
One customer had a Ruger .22 77/22 Varmint rifle re-crowned by a friend who owned a Brownell's cutter.

He had it muzzle slightly UP, and a chip fell into the barrel and badly scored the bore.

November 3, 2005, 01:34 PM
on several (milsurp) rifles...Once you buy the squaring tool and cutter, you just need a pilot for additional calibers...One note however, USE CUTTING OIL, otherwise you'll get "chatter"..WD-40 works OK, but if you can get regular machine shop cutting oil, it's better. Shouldn't be able to damage the bore, no matter how you hold the gun, but I did all mine with bore horizontal (in a vise) which allows you to keep even (moderate) pressure on the tool...

Harry Bonar
November 3, 2005, 06:47 PM
Dear Shooter:
The good piloted muzzle facing, crowning tools are the most accurate and best way to crown a muzzle since you are aligning everything with the bore!
Harry B.

November 3, 2005, 11:09 PM
Dave Manson’s tools will have superior quality and probably be more inherently resistant to chatter. However, I bought the Brownell’s tools back in the early 90’s before Dave left Clymer to set up his own shop, and have been satisfied with them with the addition of an odd trick. I once started a crown on a sporter barrel that developed a chatter pattern I just couldn’t clear cutting by hand. Rather than risk chip scoring by going muzzle-up under the drill press, I adapted the cutter to an 8” long ¼” hex drive flexible extension shaft inserted into the chuck of my battery powered drill/screw driver set to low gear and run slowly. The flex shaft, slightly bent off axis, winds up just enough to jump the cutter across chatter grooves and so cuts the peaks and levels them until cutting smoothes out.

Military surplus barrels typically have funneled rifling at the muzzle caused by steel cleaning rods; particularly the segmented kind. I use a hacksaw to cut back the muzzle as much as is practical to remove the affected rifling, then use the 90° cutter to remove any error in squareness from the saw cut. Then I apply the final angle crown cutter (and chamfer the outside with a file). If you don’t square first before cutting an angled crown, aside from looking crummy, you will bias the cutter to one side, lean the pilot to its limit, and get a crown funnel that is slightly taller on one side than the other. This guides muzzle gasses a little unevenly as they escape around the back of an exiting bullet, and can cause measurable group size increase (see Harold Vaughn’s Rifle Accuracy Facts for why).


Ace of Spades
November 4, 2005, 08:29 AM
Thank you all for the info. I bought the Brownell's tools.

November 4, 2005, 10:32 AM
EGADS!!!! cutting fluid. As a machinist, I have used them all. May I rec Mike-O-Cut????????? Clean the bbl immediately because some of the cutting fluids are actually corrosive.

November 4, 2005, 12:55 PM
What I have found that works best for me and gives a smooth cut is common everyday honing oil. Nothing corrosive about it and it helps keep the tools sharp longer.

November 5, 2005, 02:07 PM
Honing oil or any other mineral oil works. A bottle of store-brand non-detergent 20 weight will serve, too, and is probably the cheapest approach. But I have another thought: Years ago a tool maker taught me the trick for tapping a blind hole was to pack it with Crisco. It not only lubes the cut but carries the chips up out of the hole as the tap displaces it. Packing Crisco around the cutter between the edges and the pilot would tend to keep chips from working their way in, so I would recommend this approach and will try it myself when an occasion next arises.


November 5, 2005, 03:08 PM
never used crisco, but have done that with lard. I normally use a white grease to do that even now.

Harley Quinn
November 5, 2005, 03:35 PM
Always use cutting oil to cut and lubricating oil to lubricate. One is for cutting the other is for lubrication.

I am not sure if that makes sense to a machinest as a rule, but he convinced me.


Harry Bonar
November 5, 2005, 09:26 PM
Dear "crowners"

Take a small peice of denin (blue jean material) cut a hole for the pilot and make sure material goes under the cutter and that will stop all chatter. Maybe two thickneses!
Do the same when you're reaming a smaller hole with a drill bit - use two or three thicknesses.
Harry B.

November 6, 2005, 09:57 AM

If I understand you correctly, you are packing the cutting teeth. I've used chalk to load file teeth for years. It stopps pinning and achieves a smoother finish. Using denim or other cutter packing as a chatter damper hadn't occurred to me. Like chalking the file, it will likely slow cutting but improve surface finish. Chalking the cutter would probably work also. I'll have to try it. Thanks for posting the tip.


Lubrication allows cutting tools to apply more pressure to the cut without jamming the tool or chipping its cutting edges. It reduces chatter by preventing grabbing in the cut. It also reduces friction heating. So most any lube will at least help. If you search the web there are lots of examples even of dry lubes extending tool life and increasing cutting speed. Thinner cutting fluids (water solubles, for example) wash chips out more rapidly and cool better.

There is a tendency (I don't know the reason for this) for metal to cut more easily in the presence of some chlorinated solvents and other chemicals. You can actually feel a tap being easier to turn into the work if you use Tap Magic, for example. I have always assumed this was a weakening the metal bonds by chlorine radicals looking to react with iron? Mete can probably tell us if he sees this post. High sulfur cutting oil maintains its lube film through the pressure better than conventional oil. I don't know if acid radicals formed by the sulfur and trace moisture are doing some of the same thing the chlorine does or not? I know I don't want chlorine or sulfur left on a finished piece, because they will tend to promote corrosion under humid conditions, so I always flush them off and put a protective lube in their place. But for the fastest and smoothest cut, these specialized lubes do work better.


Harry Bonar
November 15, 2005, 06:36 PM
Yea, I've used chalk of my files (draw files) and it's great.
An old muzzle-loading gunsmith, Dave Taylor, of Little Hocking, Ohio told me about the denim for enlarging a hole, or "loading the teeth" as you say on a reamer, etc.
In the hand made muzzle-loading days the reamer was backed with a hickory scraper, and as it reamed the bore the wood wore slightly and caused the taper bore so desireadble in a rifle bore.
The milling machines I have (all but one) were the property of the Co., I worked for and I'm losing them now. I'm going back to my first and most precious days when I made muzzle-loaders, (I'm 70 now) and I think I'll just finish up with them - they are the most precious arms (and the most accurate) that exist, and the smell of black powder smoke is delightful.
With a faithful wife of 51 years, a warm shop, and a good dog I'm content to do this. :) Old "Brownie" my Australian Shepherd even comes on the bench and watches me work - God bless old dogs, good beer and guns!
Harry B.
P.S. I'm really finding peace with myself with this. It's pleasant to just work on muzzle-loaders for you use almost every craft existing (except playing cards or golf which I detest!) and going back to youth and old age at the same time - young people today that buy these so=called, plastic bubble packed abortions called muzzle loaders ought to build a real one - it is pleasant!

November 15, 2005, 11:17 PM

Yes. Nothing more satisfying than working with your hands. The word [I]manufacture[/] literally means "hand fabrication" which we colloquialize as "made by hand", though what is called manufacturing today has as little to do with that as possible. I've also taken great pleasure in reading the late David Gingery's books on how he built a machine shop from scratch, starting with the metal foundry. Reading them got me interested in scraping and the geometry of making flat surfaces and true right angles and parallels without any modern measuring tools. A fascinating business and rewarding activity in that it connects you with your ancestors in a curious way.

Your mention of Mr. Taylor's name sounded familiar. I live in Ohio. I think my father may have taken a class of his 15 or 20 years ago? It was someone teaching the hand making of muzzle loaders. I recall dad mentioned the method of drawing a spring to temper was, after the quench, to light the oil it was quenched in and let that burn out. I'll ask pop about it. At 84 he is still actively shooting.


November 16, 2005, 08:42 AM
Harry, I am hoping to one day be able to make my own muzzle-loader, I feel that it should be a very satisfying project.
I wish that here in AZ I could find someone that had the skills to learn from.
I do enjoy your posts, I find them very informative......
Thanks for posting