How Hard is it to Crown Your Own Barrel?


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Ranger30-06
November 12, 2011, 12:14 PM
Pardon me if this is a really stupid question, but I have been thinking about this for a while.


My question is: How hard is it to crown a barrel yourself? I mean like take a Dremel and a pointed grinding bit, stick it in the end of the barrel as straight as possible, smooth it out with a polishing bit, then clean up the barrel with a normal cleaning brush. Isn't that all gunsmiths do? Am I missing something?

Thanks.

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gennro
November 12, 2011, 12:16 PM
Thats a good way to ruin a barrel right there.

rcmodel
November 12, 2011, 12:36 PM
Yep!!
No way you can do it with a Dremel and get even close to a perfect edge, which is the whole purpose of crowning in the first place.

The old gunsmith Tried & True way is:

1. Cut the barrel if necessary.
2. True it up perfectly square with a file and a machinists square.
3. Use a large round head brass screw in a drill with #240 valve grinding compound.
4. Rock and rotate the drill continuously while spinning it and it will lap a perfect crown.

rc

Ranger30-06
November 12, 2011, 05:06 PM
Wow ok that makes sense. Thanks guys!

Jim K
November 12, 2011, 05:46 PM
That "old gunsmith tried and true way" was never used by any gunsmith I know, and I am a bit surprised to see rcmodel advocating it. A really good crown job needs a good lathe, not a brass bolt which can cut into one side or another with no way to keep it in line with the bore.

If a lathe is not available, there are some crowning tools (Brownells sells them) that can do a good job if used carefully.

Jim

rcmodel
November 12, 2011, 07:06 PM
No less a gunsmith then Roy McFarland wrote a gunsmith book published in 1965.

In it, he writes about using a brass screw lap to cut a perfect crown, and how to do it.

I used the method on the first 03A3 Springfield sporter I built.
It shot 1 MOA then, and it still shoots 1 MOA now.
It worked then, and it will still work now.

A large round-head brass screw used in constant motion in all directions will not cut more on one side, or off center, because it can't.
It is self-centering in the bore, and the constant movement & rotation keeps it from cutting more on one side then the other.

At least it is a heck of a lot better then trying to grind a crown free-hand with a Dremel tool!!
Or even chucking a barrel in a 3-jaw lathe chuck instead of dial indicating it in a 4-jaw to center the bore!

If you don't have a lathe or know how to use one if you did?
You do with what you got.

If you haven't done it, don't knock it!

rc

JohnKSa
November 12, 2011, 10:10 PM
I redid the crown on my TC Encore .223 rifle because it looks like the tooling that Thompson used to do the crown was badly worn. I didn't try shooting it before the recrown, but after the recrown the barrel shot better than MOA at 100 yards.

I used a method similar to the procedure described by rcmodel which is, by the way, identical to the method recommended by James V. Howe, in his work "The Modern Gunsmith", published originally in 1934.

Howe recommended using "flour emery" and olive oil to create a home-made lapping compound and referred to the entire operation as "lapping the muzzle". He also gave general guidance on picking the specific screw-head diameter for a given muzzle size. What's interesting is that Howe recommended "lapping the muzzle" using the brass screw method even in the case where a gunsmith might have a lathe available.

Carl N. Brown
November 12, 2011, 10:29 PM
The method described by rcmodel was and is used by traditional gunsmiths without a lathe. It is hard to mess up. Round will seek the center of a cylinder.

Seedtick
November 13, 2011, 05:09 PM
Brownells sells crown laps.

POWER CUSTOM BRASS MUZZLE CROWNING LAP (http://www.brownells.com/.aspx/pid=855/Product/POWER-CUSTOM-BRASS-MUZZLE-CROWNING-LAP)

45 BRASS MUZZLE LAP (http://www.brownells.com/.aspx/pid=679/Product/45-deg-BRASS-MUZZLE-LAP)

I've never messed with a crown so I don't know it these work or not?

Seedtick

:)

rcmodel
November 13, 2011, 05:13 PM
Oh they work.

But I can't see paying $14.00 bucks for something a $1 brass Round Head screw ot bolt from the hardware store would do as well.

rc

mike.h
November 13, 2011, 05:57 PM
A brass screw, flour and olive oil, ...sound so good I may have to try it:)

W.E.G.
November 13, 2011, 06:05 PM
Zippety doo-dah....

http://i227.photobucket.com/albums/dd7/rkba2da/WECSOG/02_dremel_muzzle.jpg

http://i227.photobucket.com/albums/dd7/rkba2da/WECSOG/03_almost_cut.jpg

Zippety ayyyy....

http://i227.photobucket.com/albums/dd7/rkba2da/rifle%20pics/FAL/izzymuzzle.jpg

W.E.G.
November 13, 2011, 06:07 PM
I did "true it up" with a file and some sandpaper before cold-bluing.

Ranger30-06
November 13, 2011, 06:42 PM
W.E.G. What is that in the second photo??

JohnKSa
November 13, 2011, 08:00 PM
A brass screw, flour and olive oil, ...sound so good I may have to try itEmery flour, not just flour. It's a very fine abrasive powder.

egg250
November 13, 2011, 08:22 PM
I have a .303 British SMLE that needed some crown work. I took it to a gunsmith to be recrowned. He charged me $25.00 and it looked like he took a Dremel tool to it. I could see the grinding marks and the crown was lopsided. I took my case chamfering tool and reworked the crown with it. After about 20 minutes the marks were gone and the crown was even. I haven't shot it since, but I am looking forward to seeing what the improvement might be.

Howard Roark
November 13, 2011, 08:45 PM
Dave Manson makes a a great piloted hand turned crowning tool. Here is a youtube video of him using it: http://www.youtube.com/watch?v=-Xpzv1Spsnk

The only way to get a perfectly square crown is parallel off the bore and this tool does that. I've used this tool and it works great if you don't have a lathe or can't get the action chucked up in the lathe. That said, the price of this tool is high for a one-off job.

Elkins45
November 14, 2011, 09:04 PM
The Brownell's gun smithing book advocates the brass screw method, so that's a pretty credible recommendation.

Striker Fired
November 15, 2011, 10:22 AM
I'm lucky enough to be able to all my barrels in to work and chuck them up in the lathe and make everything perfect,I usually put a recessed target crown on them. Several of my handguns the before and after groups were quite different,so now it is one of the first things I do when I get a new gun.

FTG-05
November 15, 2011, 12:51 PM
I use this: http://www.brownells.com/.aspx/pid=628/Product/79-deg-MUZZLE-CROWNING-CUTTER

And then follow it up with the brass screw and lapping compound.

Ranger30-06
November 15, 2011, 01:03 PM
I use this: http://www.brownells.com/.aspx/pid=628/Product/79-deg-MUZZLE-CROWNING-CUTTER

And then follow it up with the brass screw and lapping compound.
I guess that cutter fits into a lathe then?? Do they make ones for use in a power drill??

rcmodel
November 15, 2011, 01:15 PM
You turn it by hand.
It says in the item description:
"-20 thread fits Brownells muzzle chamfering handles.
http://www.brownells.com/.aspx/pid=25439/Product/RIFLED-SHOTGUN-MUZZLE-FACING-PILOTS

Or, you can buy this for use in a drill.
http://www.brownells.com/.aspx/pid=1032/Product/MUZZLE-FACING-CROWNING-CUTTER-DRILL


BTW: Be sure to use plenty of cutting oil!

rc

Ranger30-06
November 15, 2011, 01:25 PM
Derrrr shoulda read a little more there :banghead: Thanks though.

Jim K
November 16, 2011, 06:43 PM
I have and have read those books. I still wouldn't (and didn't) use a brass screw to cut a crown. I did have the luxury of a lathe with a hollow headstock which makes things a lot easier.

Jim

W.E.G.
November 16, 2011, 06:47 PM
W.E.G. What is that in the second photo??

http://i227.photobucket.com/albums/dd7/rkba2da/WECSOG/03_almost_cut.jpg

That's the barrel cut almost all the way through.

http://i227.photobucket.com/albums/dd7/rkba2da/WECSOG/04_cut_threads.jpg

Strykervet
November 16, 2011, 07:56 PM
The cutter goes in a lathe. I've done it by hand with the tool and a handle and it turned out okay, but I wasn't doing it on a very expensive rifle. It was a beater Enfield I sporterized, and I crowned the barrel using the proper tool a machinist buddy gave me, but I did it all by hand. It took a while, but I got it done. The end result was just as fine had it been done by machine, and it shot just fine, but I may have been lucky, and I wouldn't think of doing this to a nice barrel or a nice rifle, especially one that shoots sub MOA.

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