Best way to recrown barrel

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  • Last Post 06 April 2009
GBertolet posted this 25 March 2009

I have 2 guns I would like to recrown. One is a Rem 788 in 30 -30 and the other is a S&W mod 18 in 22 cal.The Rem has pitting at the muzzle but no other visible damage. The S&W has a very light burr on one of the lands. The accuracy is disappointing on both guns.

One person said to use a 9mm fmj bullet in a drill with lapping compound, and run it against the muzzle until it cleans up. Others say get a crown cutting tool with a pilot and T handle from a gunsmith supply, which would run about $100 and do it that way. Which way is best? I have heard of guns shooting poorly and when all other corrective measures failed, a recrown improved accuracy, even when the muzzle looked fine beforehand.

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JeffinNZ posted this 25 March 2009

I am inclined to believe the only way to recrown with complete confidence is in a dependable lathe.  I had my .380 Rook recrowned when I bought it.  My man of choice is a local benchrester and very clever machinist.  It took him twice as long to set up the job as to preform the job but man oh man, the crown is perfectly square.

Cheers from New Zealand

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TomG posted this 25 March 2009

"G"   The really best way to recrown a barrel is to set it up in a lathe in a 4 or 6 jaw chuck and indicate it on center off the top of the lands.  Then cut the crown with a very sharp HSS tool.  Making a very, very, very light cut on the last pass.  

If you crown it by wobbling a lap around the crown you will get a crown but who knows how concentric it will be to the bore. 

The next better way is to use a piloted crown cutting too.   It will pilot off the bore with a pilot that is small enough to fit ANY bore.  There will be some slop and a chance the tool will chatter and wipe burrs off the sides of the lands. It doesn't even come close to the accuracy of a properly done lathe job.

When I was doing them for customers who wanted benchrest accuracy, I would usually finish it up with a brass lap held in a tailstock that was exactly on center to the headstock and lap the ends of the lands to the point that it just broke the base of the lands.

If there is a small burr after a lathe cut, a brass brush passed thru the bore will take it out. Also, it will be shot out with the first shot thru the barrel. Any precision gunsmith who is worth his salt will now have a Hawkey borescope and can look at the crown with it and verify that he did a good job for you. 

If you want a so-so job you can get that by wobbling a lap against the end of the bore.

Tom Gray

 

 

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AMMOe posted this 25 March 2009

Brownells sells barrel crowning kits. They are pricey and the pilots are sold by caliber. I used on on my Winchester .222 after the previous owner had bulged the barrel and it cleaned up nicely and the gun shoots 1/4MOA with about anything.

I have owned several 788 30WCF's and some of them wouldn't shoot, period. Or I should say, gave mediocre accuracy... even after I recrowned them in my lathe. No guarantees there.

I'm guessing that unless that ding in the S&W crown is very pronounced it is not your problem. There are a fist full of things that will ruin accuracy in a revolver before you work your way that far forward. The forcing cone on my 17-2 was so far off center the bullets were splashing lead all over the cylinder face and the targets were dismal. I recut the forcing cone square with the bore and the gun became a tack driver.

Just a thought....~AMMOe

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CB posted this 26 March 2009

AMMOe wrote: Brownells sells barrel crowning kits. They are pricey and the pilots are sold by caliber. I used on on my Winchester .222 after the previous owner had bulged the barrel and it cleaned up nicely and the gun shoots 1/4MOA with about anything.

"Best way to recrown barrel” ?

I have been using the same outfit for years, hand reamer cutter with pilots. I did my championship shooting Savage and it'll shoot 1/3MOA. I use the reamer on all the 22rf re-lining jobs I've done and they can shoot down to .2” groups at 50yds. There is nothing wrong with hand reamers.

Like most machine work, the skill aspect still needs to be considered, both lathe work or reamer work, careful, considerate and precise attention. Reamer chatter can be stopped by dead-heading the pilot against a rod inserted from the action end and secured.

Like Tom, I don't mess with the cutting job once it is cut, just knock down the light burr some and quit...............Dan

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Ed Harris posted this 26 March 2009

The piloted crowning tools sold by Brownells are simiiar to the ordnance corps versions used at second level maintenance in repairing the Springfield, Garand and M14 rifles. They will do a concentric job without a lathe if you have the correct fitting pilots and are careful.

If it is necessary to cut off the barrel first score the barrel all the way around with a tubing cutter, to give you a circumferential guide all the way around the barrel. From this you can go around the barrel slowly and carefully pulling a hacksaw to you and get the cut reasonably square. From there true up with a mill b** file, checking frequently by eye using a carpenters square, then use the Brownell tool to finish the cleanup.

I have cut many .22 rimfire and .30 cal. barrels using this method, and even without the Brownell crowning tool you can do a completely satisfactory job for hunting rifles doing the job carefully by eye and finishing them up by hand using Brownell's revolver ball burnishing tool, or a large round-headed brass screw, using AA clover paste in a hand cranked drill. But I do agree that a lathe is best, if you have one.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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R. Dupraz posted this 26 March 2009

1st choice--good machinist that knows what he is doing with a lathe and cares enough to set it up right.

2nd choice-- which is what I do with muzzle loader barrels is to use the Brownell's facing and crowning tools with a T-handle because I don't have a big lathe. And I turn pilots for the various bore sizes that I need. These are turned just undersize enough so that a slip of one of my former business cards when wrapped around the pilot with a drop or two of oil, snugs it up nicely in the bore. No play or chatter.

So far all the ML's have put five shots in an inch at 50 yds. That target that I posted on this forum a while back was shot with  my .45x2.4 Shiloh and PP after the muzzle had been faced off and recrowned with the above tools.

If I didn't fool around with this stuff and wanted a crown or two fixed, I'd just take it to a smith with a lathe.  

 

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KenK posted this 26 March 2009

My little brother has always been fearless when it comes to stuff like this.  He also never doubts his decisions and is very capable with tools.

He cut off several rifle barrels using exactly Ed's method when we were still in school and they shot just as well as with the factory crown.

I worked in the tool and die business for a good while. This kind of thing can be done by hand by some and can't by others.

However; if you try and fail, you have only lost but a tiny bit off the end of your barrel so why not give it a shot?

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GBertolet posted this 06 April 2009

An update on the 788 Rem. I found another burr about 1/4 in inside the muzzle, it happened to have a sliver of lead stuck on it. I don't have a bore scope to see if anything else is damaged. Since the rifle was free and there is a chance the barrel is junk anyway I would like to try cutting about 1/2 inch off the muzzle. My question is could I use my 14 inch chop saw to do this with? It has its own vice and cuts square. If I go slow things shouldn't get too hot.  Does anyone have any experience trying this or am I crazy for even considering this method over the hacksaw?

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Antietamgw posted this 06 April 2009

Maybe a few passes with a new bronze bore brush or some J-B compound will clean up that sliver. Push a nice white patch in from the breech to just short of the sliver, take a look with a little magnifying glass and your mini-mag light, it's surprising how much more you can see. If you decide to cut it, I believe a chop saw would be a last resort. Things go wrong quick under power and since your barrel is tapered, I think you would have a better chance of staying close to concentric to the bore with the tubing cutter method above than guessing the taper and trying to offset the barrel in the vise on the chopsaw. Good luck with it, be a shame to have to cut the barrel on a 788 in .30-30.

Keep your plowshare and your sword. Know how and when to use them.

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GBertolet posted this 06 April 2009

There is definitely an edge or step in the rifling. I can feel it using a toothpick as a probe. You have a point about the tapered barrel, so a hacksaw seems in order. If I screw it up, I have only cut off a half inch and can take it to a gunsmith to make it right.

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