Barrel Crowning

[tjsimmon]

This has probably been discussed but I just couldn't find it. I have  22Cal and 25cal Marauder that I am going to rebuild with JSAR components and I want to crown the barrels and would like some inf on the best way to do this? Any help and direction would be greatly appreciated.

[skorec]

I am using some Ball Shape Rotary Point Burs Bits

https://www.ebay.com/itm/7pcs-Diamond-6-8mm-Ball-Shape-Rotary-Point-Burs-Bits-for-Handpiece/142839896210?hash=item2141ebd892:g:CzYAAOSwTodbK7Oj:rk:9:pf:0

[Tucobenedicto]

Or you can do the classic way,a round head brass screw and a bit of Permatex valve grinding compound or something equivalent.

[Wayne52]

I've been doing it with the brass screw myself, works good like Fabio said. 

[csitas]

I agree with Wayne also. I use the brass screw and a small dab of valve grinding compound on a round head brass screw. Chuck the screw in an electric hand drill and wobble it around in the end of the barrle. This cuts nice and slow.  The trouble with stones and burrs is they cut tooo fast. Once you cut it too much, too bad.This will rival a pro job if you take your time.

[Jeff Marshall]

I agree with Wayne also. I use the brass screw and a small dab of valve grinding compound on a round head brass screw. Chuck the screw in an electric hand drill and wobble it around in the end of the barrle. This cuts nice and slow.  The trouble with stones and burrs is they cut tooo fast. Once you cut it too much, too bad.This will rival a pro job if you take your time.

As far as a burr, I would be afraid that it would catch or chatter.

A fine properly shaped stone used carefully at slow speed is great
if used with discretion. Unless the crown is really sloppy and actually needs reshaped, they are not necessary. Of course, finish up with
screw and grinding compound.

I have mostly used steel screws with valve grinding compound with great results just because that is what I had around.

[D-RIG]

The brass screw works great , I use JB Bore paste and then
I use the JB Bore Bright with the brass screw works great , It
does take 10 or 15 minutes to do the job .

[Verminstalker]

The best way to get a true and consistent crown is by using a muzzle chamfer and caliber specific arbors to keep it squared up while cutting. I've had excellent results with both 45 degree and 11 degree cutters.

[nervoustrigger]

Like others have said, a brass screw and J-B (or Flitz, rottenstone, etc.) will produce good results.  You don't want to remove much material, just enough to remove any burrs that may be present from the factory machining operations.  Here's a recent example I did...in this case, I had to start by cutting off a short section off the muzzle to remove some damaged rifling.  There's more detail in the barrel link in my signature.

[skorec]

YES  Bore inspection at the muzzle is veeeeeery important and as Jason sad it is necessary to cut firs barrel part with much damage bore .  Also lapping the barrel bore with grinding compound may fix not too deep damages. Lapping the choked barrel may also decrease the choking which can increase accuracy mainly  for extra heavy pellets.
After Crowning with mentioned diamond ball drills i always   do lapping of bore at muzzle.

[subscriber]

To achieve the .25 Marauder barrel crown shown below; read this post: 
https://www.gatewaytoairguns.org/GTA/index.php?topic=137096.msg1378450#msg1378450

[Slavia]

I have had good luck with a round head brass screw and abrasive.  I have read that the abrasive embeds itself more readily in the softer brass than in harder steel.  As has been mentioned, there are many abrasives that will fit the bill.  I currently use automotive paint rubbing compound, but I have even used toothpaste.  It all depends on how long you want to devote to the process.  Not all toothpaste is the same:  https://www.williamsonperio.com/wp-content/uploads/2014/07/Toothpaste-Abrasiveness-Ranked-by-RDA.pdf  It might even be advantageous to go to a garage or body shop and beg a tablespoon of abrasive.  A tub of paint rubbing compound at Walmart isn't all that expensive, but I now have enough to do about 10 gazillion crown jobs.

[Gear_Junkie]

Good info in this thread!

[Stinger177]

Good info in this thread!

I agree completely!! Where else can you get info like this but here?

Not all toothpaste is the same:  https://www.williamsonperio.com/wp-content/uploads/2014/07/Toothpaste-Abrasiveness-Ranked-by-RDA.pdf

I LOVE this place!!

[kzz1kaw]

The best way to get a true and consistent crown is by using a muzzle chamfer and caliber specific arbors to keep it squared up while cutting. I've had excellent results with both 45 degree and 11 degree cutters.

+1😎👍🏾

[tjsimmon]

Thank you all for the awesome help. I will post my results when I get it done.

[Wolverineshooter]

Great info.

[skorec]

The best way to get a true and consistent crown is by using a muzzle chamfer and caliber specific arbors to keep it squared up while cutting. I've had excellent results with both 45 degree and 11 degree cutters.

Where to buy muzzle chamfer at EU or China/e-bay ?

[Verminstalker]

The best way to get a true and consistent crown is by using a muzzle chamfer and caliber specific arbors to keep it squared up while cutting. I've had excellent results with both 45 degree and 11 degree cutters.

Where to buy muzzle chamfer at EU or China/e-bay ?

Peter, I think Ebay may be your best chance unless you have someplace in the EU that sells gunsmithing tools. The shipping and customs fees may be to costly if you bought it from the United States.