Chopping and Crowning a Barrel

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Hi, I am planning to cut down and recrown a Mosin Nagant barrel as part of a sporterizing project. What tools do I need to recrown the barrel?

I am looking on Brownells and they have a muzzle crowning cutter and pilots. The cutter is shown here: http://www.brownells.com/gunsmith-t...utters/79-muzzle-crowning-cutter-prod628.aspx. Do I want the 1/2" or 3/4" one?

Also, I think there should be a handle or something to attach to the non-cutting end. Where can I find this as I'm having trouble finding it on Brownells.

Thanks!
 
A hacksaw, and machinist or small carpenters square, a fine cut file, a brass round head screw & valve grinding compound, and a drill motor of some sort.

Saw the barrel off, file it perfect square, and lap the crown with the brass round-head and grinding compound.

Any half decent home shop will have the hacksaw, square, file, and drill.

You may have to buy a brass screw and grinding compound.

Total outlay should not exceed $10 bucks.

rc
 
RC, can you please describe in a little more detail how to crown the barrel with those items? I understand how to cut the barrel off with the hacksaw and file it square. However, I get lost with the whole brass screw and valve compound part. If you have pictures or a video link, that would definitely be beneficial. I'm like your idea as the tools that I was looking at from Brownells will likely cost as much as a Mosin. Haha.
 
Lapping the crown on the barrel is a good Cheap way to do it, but if you want an accurate rifle, you should crown it with the hand crowning tool like from Brownells.
I have the SET that came with the 90 degree cutter and 45 degree champher cutter, a pilot for my caliber, plus I got the 79 or 11 degree target cutter ond several different pilots for different calibers.
I think it is listed under Champher and facing one caliber sets, and the handle comes with it.
But if you order one, do yourself a favor and make sure you order one pilot in .30 cal, and one in .311.
The MN barrels are not always true or well worn being an original .310 bore.

I do lots of barrel cutting and sporterizing, so all the tools are worth it to me.
But use your best judgement if you only intend to do only one barrel.
But Squaring an lapping is good enough for general range and field use.
 
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If the barrel is tapered, getting it hack sawed and filed true square by hand can be a bit of a task.
 
chopping and recrowning are easy. the thing to watch out for is the BORE which should taper slightly at the end for accuracy and should definitely not open up. so if you cut off the tight portion, it could screw up your accuracy. not sure how to measure that though
 
Taliv you are correct but I doubt most commercial barrels have choke in them unless you have a really high dollar rifle or a high dollar replacement barrel.

Ross Seyfried wrote and article about firelapping barrels many years ago and he mentioned that if done correctly you could add a choke to the end of a barrel. But it happened because you slightly opened the bore and by the time the bullet reached the end of the barrel the lapping compound was used up for the most part. This would give you muzzle constriction. As think as long as the muzzle end isn't bigger you are okay for a sporting gun.
 
I am not going to say they are not out there.
But in all my years of working on barrels, and slugging them at both ends, I have Never run across a Barrel that was Choked at the muzzle.
Maybe on High dollar target rifles ?
But I do not think I will ever get one of these that needs shortening.
And to check for a choked or restricted barrel, this is how you would have to check it.
You run a lead slug into the barrel muzzle only 1" and then back out, then do the other end of the barrels bore, and compare the diameters of both slugs.
You do that too to check for Muzzle wear or wear right in front of the freebore.
 
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Witchhunter -- there is a famous video or illustrated article out there where a fellow took a good hunting rifle, shot base line groups with it, and then proceeded, step by step, the absolutely DESTROY the crown. At each step, he shot another set of groups with it.

There was virtually no change.

And I mean he DESTROYED the end of that barrel. He banged it, hacked it, cut it, did just about everything you could think of to it.

That gave me great solace when I hacksawed my Mosin Nagants (and I couldn't even cut straight). [Easier way to do it is with a chop saw, BTW] and then cut them square and flat with a Lee case trimmer shimmed up with McDonalds's straws to fit the bore....and then beveled just slightly with valve grinding compound in the gap of a big brass screw hand held in a 3/8" Black and Decker electric drill.

My groups got markedly better.

Give it a whirl!
 
The first barrel cut down and recrowning was done on a Mosin Nagant back in the 70's.
I cut the barrel with a Hack saw, filed it square as I could, and then cut a 45 degree bevel in the end of the barrel with a Rosehead Countersink that is used for recessing screw heads, spun in a Cordless drill motor.
I then polished the lip inside with a Ball End Hinge pin off a Antique door hinge and some Chrome cleaner, again spun in the drill motor.
The crown came out great, and was very accurate.

If I find any of those old Hinge pins laying around at yard sales and such.
I grab them up, and use them for polishing crowns, as Many of them were made of brass and are the perfect size for a crowning tool.
 
Thanks for the link Doc, that was interesting, but I'm not messing with the Gods of Accuracy. I have had two barrels recrowned by my smith, (on a lathe) both shot better after. Both rifles had opened up to an inch or so and both benefited from the work. One made it through another year and a half of prairie dog shooting, and a rebarrel is coming, the other one is still shooting around 5/8".
 
Sounds like you made up your mind Witch hunter, but there is no ju ju with crowning like there is with other gun smithing.
I have cut and crowned two milsurps: a Mosin and a No. 4 Enfield. For both of them I filled the end of the barrel with twisted paper towel, then I snugged the barrel in a padded vice, making sure the barrel was level. I then cut with a hacksaw right against the vice jaws. Next I filed the end good and flat and used a Dremel with a flexible sanding disk and water to clean it up good. When the end of the barrel was nice and smooth, I took a 3/8", round headed Dremel grinding bit and started my crowning using water as I went about it. I didn't go in far; about 1/16-3/32". I finished it of with some 400 grit wet and dry sand paper and a felt polishing bit with jewelers rouge. Looks factory.

Don't forget to clean out the paper towel and any polishing crap!
 
I cut a Savage barrel with a hacksaw, some files, and a dremel bit (used BY HAND). Shoots and looks just fine. Just keep checking to see if it's square when you're filing, and you can use anything you want to finish the crown. The important part is to make sure the end of the rifling is smooth, and there are no burrs. And cut a half-inch or so further out than you planned to... leave some room for you or a 'smith to fix it should you do something wrong.
 
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found the reference: http://www.longrangehunting.com/arti...le-crown-1.php

shot 3/4 MOA and wait'll you see what it looked like!
Click to expand...

If this study can be independently repeated and confirmed a whole lot of theory about what makes an accurate rifle will have to be modified. I've never questioned that the muzzle crown was "critical" as I was taught to protect it from day one.

Maybe a fan request to Mythbusters is in order.
 
All this talk about re-crowning your rifles, and using the most unprecise methods.
But then most guys FREAK OUT if you try to clean a rifle from the muzzle end ,even with an Aluminum cleaning rod for fear they will ruin the crown if the do that even once.
Or the guys that have a bad day at the range, and send there rifle in for recrowning.
The Best crown is NO Crown, with the barrel cut perfectly square, and only the cutting burrs removed.
But that crown being so sharp, it is subject to damage right away.
Crowning is installed to protect as best we can the sharp square edge to the bore for the exit of the bullet from the barrel.
That is why some say the 11 degree crown is best, but it doesnt provide the best protection for a field rifle.
 
Crowning is installed to protect as best we can the sharp square edge to the bore for the exit of the bullet from the barrel.
Click to expand...

The article linked suggests that even notches and burrs don't matter once the burr has been shot away! Unless the article is totally BS fiction, it really flies in the face of all conventional shooters wisdom -- which is why I'd love to see the results independently confirmed.
 
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