How I fix a bad crown

[cwlongshot]

I have had need to do this when chopping a barrel. Or just fixing a worn muzzle. Sometimes todays guns have issues here. My friends new S&W 10 mm is an example.

https://youtu.be/VPCTJDhaQKs

Hope ya enjoy.

CW

[LAGS]

Posted on the thread for Bubba barrel repairs in the muzzleloading thread is a barrel I recrowned and the tool I made out of a ball bearing.
I do have the hand tools I bought 20 years ago from Brownells also.
I have the 90° cutter.
The 11° cutter as well as the 45° cutter.
Plus plenty of pilots to fit the bore.
But I mostly use that ball bearing to polish out the crown inside the bore.
And I bought a 45° lapping tool from Brownells and an outside crown cutter from them too.
I use to do a ton of barrels for Sporters and custom rifles.

[DougGuy]

I don't use NOTHING on a muzzle unless it is PILOTED. Everything else is guesswork. I'll pass.

All the ball bearings, brass balls, carriage bolts, all they do is make a home where there is the least resistance. No guarantee of concentricity whatsoever.

My crown cutter is a 20 degree Neway valve seat cutter for small engines with carbide blades. I use a Manson double expanding mandrel that centers on the lands and the cutter is sleeved and honed to concentric and it slides down over the mandrel and is turned with a drill motor or by hand, the newly cut crown is then polished with a piece of 180 grit cloth backed abrasive held against a 20 degree aluminum lap that centers on the mandrel, and finally shined with fine scotchbrite held against the lap.

[sparky45]

Enjoyed the video CW; thanks.

[sniper]

Wow! Great video! Thank you for posting this! One problem I have always had...cutting anything square with a hacksaw, and filing square, too,, even with a large "Dratsab" file.
I did manage to pass my High School Machine shop class, tho.
But...I did go to Home Depot and bought some round-headed brass bolts in various sizes,"just in case", and I bought the McARBO lapping tool when I got the spring and polish kit for my GP 100. So far, none of my crowns have needed any attention, which may be a Good Thing!. But...If it ain't broke, give it here for a minute!

[cwlongshot]

Your very welcome guys!! CW

[ebb]

I had a guy who is a national champion benchrest shooter thread, install, chamber, and crown a barrel for me about 15 years ago. I asked how he crowned the barrel, he replied that he did it in the lathe. I asked if crowning using a round headed brass screw would work. He said that he had won national championships doing it both ways. I was surprised at his answer.

[cwlongshot]

Yes sir ebb!! It aint rocket science!! ♥️♥️

[JCM45]

Great info, CW. Thanks.

[FrankJD]

Good video. I've done 3 .22LR bbls using round head brass screws and valve grinding compound. All bbls turned out to be extremely accurate.

[PopcornSutton]

I would go along with DougGuy. I do rifles and the only way to cut a crown is in a lathe, indicated in to as small as possi ble with your setup, then pull the cuts from the bore to the outside.

[cwlongshot]

I would go along with DougGuy. I do rifles and the only way to cut a crown is in a lathe, indicated in to as small as possi ble with your setup, then pull the cuts from the bore to the outside.

You aint wrong! But it is NOT the only way.

Enjoy,
CW

[Kosh75287]

THanx for posting the video, Sir.
Most edifying to a "mechano-dilettante" such as myself. I'm still at the "makes up for lack of skill with caution and determination" level of (non)proficiency, and the clip you posted helped clear up much confusion.
I HAVE used the "glass marble + fine grit abrasive in heavy grease" method, not to CREATE a crown, but to de-burr an obviously "burred" crown. I'm not sure I followed all the "holy rules of gunsmithing" in the process, but the old bolt action returned from "minute of grapefruit" to "inside a shot glass" at ~100 yards.
I harbor no illusions about my "making" the rifle more accurate. It was a tack-driver before the muzzle burring. All that I did was remove some obstacles untimely inflicted on an otherwise fine piece of ordnance. It felt good to change it (back) for the better, though.
Mercifully, I have wrecked no firearms, up to this point. May it ever be thus.

[Kosh75287]

THanx for posting the video, Sir.
Most edifying to a "mechano-dilettante" such as myself. I'm still at the "makes up for lack of skill with caution and determination" level of (non)proficiency, and the clip you posted helped clear up much confusion.
I HAVE used the "glass marble + fine grit abrasive in heavy grease" method, not to CREATE a crown, but to de-burr an obviously "burred" crown. I'm not sure I followed all the "holy rules of gunsmithing" in the process, but the old bolt action returned from "minute of grapefruit" to "inside a shot glass" at ~100 yards.
I harbor no illusions about my "making" the rifle more accurate. It was a tack-driver before the muzzle burring. All that I did was remove some obstacles untimely inflicted on an otherwise fine piece of ordnance. It felt good to change it (back) for the better, though.
Mercifully, I have wrecked no firearms, up to this point. May it ever be thus.

Wow! Great video! Thank you for posting this! One problem I have always had...cutting anything square with a hacksaw, and filing square, too,, even with a large "Dratsab" file.

Yer SINGING my SONG, friend. More often than not, I make that dude on "Home Improvement" look like a friggin' mechanical GENIUS! I sometimes wonder if my business card shouldn't read: "Bowling balls and Anvils wrecked while you wait."

[ebb]

i had a guy locally put a Shilen on my 25-06 and i got a contoured blank from midway. He installed it to its maximum lenght and it was just too long and i didn't have any soft cases it would fit in. i was very unsure that i could get it straight enough to crown so I bought the Brownell's tool. It cleaned up my hack saw work and made it very square but it looked rough so the brass screw came out again. I totaly get doing it in the lathe if it is such you can get in a lathe without a bunch of work.

[6string]

I don't use NOTHING on a muzzle unless it is PILOTED. Everything else is guesswork. I'll pass.

All the ball bearings, brass balls, carriage bolts, all they do is make a home where there is the least resistance. No guarantee of concentricity whatsoever.

My crown cutter is a 20 degree Neway valve seat cutter for small engines with carbide blades. I use a Manson double expanding mandrel that centers on the lands and the cutter is sleeved and honed to concentric and it slides down over the mandrel and is turned with a drill motor or by hand, the newly cut crown is then polished with a piece of 180 grit cloth backed abrasive held against a 20 degree aluminum lap that centers on the mandrel, and finally shined with fine scotchbrite held against the lap.

This makes the most sense to me. Use the bore itself as the reference for crowning the muzzle or simply making sure a shortened barrel face is perpendicular to the bore.

[pworley1]

It could more esthetic than actual. https://rifleshooter.com/2018/03/do-...fect-accuracy/