Author Topic: Easy Way to Recrown a barrel  (Read 6150 times)

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Offline Huffmanite

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Easy Way to Recrown a barrel
« on: February 09, 2010, 11:47:01 am »
A year or so ago I bought an old military surplus rifle that had been sporterized.  Previous owner had shortened the original barrel and done a so called bubba job recrowning the muzzle.  I'd taken the rifle to range a few times and its accuracy was rather poor and I blamed its inaccuracy on the bubba crown job.  Curious how bad, uneven the crown was, I took my Lee reloading tool for hand trimming brass and with the best fitting spindle on it, I inserted it in the bore.  Of course the spindle was loose in the barrel.  So I used a piece of aluminum cut from side of a beer can, wrapped it around the spindle and reinserted it in the muzzle.  Nice tight fit and the aluminum protected the rifleings.  All I really wanted to do was to lightly twist the case trimmer and check for how level the crown had been cut.  It worked, I could now see the scratches from the trimmer's 4 cutting edges, easily revealing the uneveness of the homemade crown.  Knowing the steel in the Lee trimmer tool to be a lot harder than the metal in the barrel, I decided see if I could use the Lee tool to recrown the barrel by hand turning it with a steady pressure.  About 15 minutes later, I had a pretty nice looking flat crown.  Then I took a carriage head bolt, coated it with a fine valve grinding compound, put it in my electric drill and lapped the edge of the muzzle bore.  Took rifle to range and discovered the accuracy of the rifle had improved considerably.  

Shortly after this, I mentioned my use of the Lee case trimmer to recrown a muzzle in the chat room of Surplus Rifle . Com, showing them some pics I'd posted on Photobucket of my experiement.  Guys in chat room thought it was neat and they suggested that I post it in the gunsmithing forum of Surplus Rifle, which I did with pics included.  My idea of using the Lee Case Trimmer to recrown a muzzle was warmly received, tried successfully by others, and soon my post was made a sticky at the top of the gunsmithing section.  Of course, a gunsmith took exception to using a $8 or less Lee case trimmer to crown a barrel that he charged $75 dollars for doing.  LOL, can't blame the gunsmith for that.

Anyway, this morning I just used my Lee Case trimmer on a M1917 30-06 sporter crown that needed some work.  This is my 4th time to use a Lee case trimmer to recrown a barrel and like my first three times, I expect the rifle to shoot more accurately.  Just thought I'd share this recrowning method to you.


Offline Tommyt

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Re: Easy Way to Recrown a barrel
« Reply #1 on: February 10, 2010, 07:52:56 am »
Thank you
Years Back I was asking how to re-crown a old 30-30 I had and from using it as a leaning post I damaged it
Jack Belk at that time was visiting the board Jack sent me a note that I think turned to a post not a Sticky
But any way He told me Just as you said LESS the Trimmer which now I'll add to my list
He said to use a Brass Slotted screw and valve grinding oil
He also I think this was him?? said you can use many things to clean them like a burr
So I did in fact try the burr tool as I didn't have the grinding oil
I used motor oil while I re-crowned and some how
I came out with a Good Reborn 30-30
Wish He was still posting some where
I did a search for him just a week or so ago
Thanks for the Great info

Tommyt
"Not everything found on the internet is accurate"
Abraham Lincoln

Offline Huffmanite

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Re: Easy Way to Recrown a barrel
« Reply #2 on: February 10, 2010, 11:07:32 am »
Tommyt,  You are right about using a Brass sloted screw to do what I did with a carriage bolt.  I just prefer to use the rounded head of a carriage bolt since they are easier to find than a brass sloted screw that has a large enough head.  Of course the grit in the valve grinding compound would embed into the softer brass aiding the removal of metal from muzzle.  Use of a Lee case trimmer kinda produces what is called a target crown.  Lee trimmer will leave a rim around outer edge of muzzle, flat area, and then the beveled area of the carriage bolt/slotted screw.  Here are a couple of pics from first time I used the Lee tool. 

Offline Badnews Bob

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Re: Easy Way to Recrown a barrel
« Reply #3 on: February 10, 2010, 01:11:48 pm »
Wonderful ideal, I have cleaned up a couple crowns with a brass screw and cut one once with a ball stone in a dremal on a old mauser. The old barrel throat was shot out and we shortend it and crowned it just to see if we could. It worked taking it from about a 8" pattern at 75 yards to a 5" or so pattern. :D
Badnews Bob
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Offline Tommyt

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Re: Easy Way to Recrown a barrel
« Reply #4 on: February 11, 2010, 09:10:26 am »
Huffmanite

  Excellent! The picture looks so good I may buy a beat up gun to play with
If your wanting Brass Slotted try the Plumbing supply,even at one of the local Depot's
 I just enjoy the learning and the little tricks
Jack also (lost copies) wrote me how to Jewel a Bolt. I'll give it a go off the top of my Head
 Drill Press and a Jig the moves straight in one direction and Back the same
I have thoughts of a Kids Match box size car/truck modified
on that you make something to hold the bolt you then put a rail on the Press table
   I forget what was used But you use per se' a Ceramic rod or small drill bit
Chuck it of center BINGO can you see where this is ?
Its simply a straight rod that will scar your bolt but as it slowly goes round and round in this odd egg circle
It also is Exact in Rotation, so now while its turning and (I believe Slow) you drive your match box Jig
back and forth with the cutting rod just touching  your bolt after a few Passes you turn the bolt some
 on your box Jig and repeat
 I hope my Back arse word type was good enough to get the Picture when my PC crashed and un-recoverable
I lost lots of things like this,along with Pictures to show the procedures

Tom
"Not everything found on the internet is accurate"
Abraham Lincoln

Offline mtbugle

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Re: Easy Way to Recrown a barrel
« Reply #5 on: February 11, 2010, 06:31:24 pm »
I would assume it best to cut off the shank or stem of the brass screw so nothing in bore to scrape grit against rifling while doing the crown?
Thanks Don.

Offline Huffmanite

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Re: Easy Way to Recrown a barrel
« Reply #6 on: February 11, 2010, 07:45:11 pm »
mtbugle,

chuck the threaded end of screw into drill, coat the screw head with grinding compound, center slotted screw end in muzzle of bore and drill.  Add grinding compound as needed.  Drill till you are satisfied with amount of metal removed from edge of bore.

Offline bubbinator

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Re: Easy Way to Recrown a barrel
« Reply #7 on: February 21, 2010, 10:52:11 pm »
This something to consider. On the range one day one of my agents had been carrying his Sig P220 .45 in a belt slide holster and the seatbelt buckle had damaged the muzzle over time. It was mess.  His scores were lower than normal and the weapon would not shoot a good group even from a rest.  I took a marble from my range box, coated it with JB Bore Compound and between courses of fire twisted it around and around until the scratches and digs on the muzzle were polished away (about 15 minutes worth of application).  We retested the weapon and the groups improved dramatically. Total investment and 10 cents! An old country gunsmith had given that tip to another firearms instructor some yrs. back.  This might not work on a benchrest gun, but for what your talking about it may help.

Offline bilmac

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Re: Easy Way to Recrown a barrel
« Reply #8 on: February 22, 2010, 04:48:51 am »
I too have crowned a lot of muzzles with bolt heads. I use a variety of different sizes of the bolt heads which is a lot faster at making an old fashoned rounded crown than just grinding away with the same size.

Offline gunnut69

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Re: Easy Way to Recrown a barrel
« Reply #9 on: February 23, 2010, 10:14:34 am »
It is much improved in action and result if the drill is moved in a slow circle as the head turns in the muzzle. This will qualize the crown. There are tools available that function in roughly the same manner but are more accurate and produce better results. A lathe is the best venue for this but a lot depends on what result is needed. Jewleing a bolt doesn't work well with a hard tool. The abrasive needs fairly even pressure to cut even grooves in the rounded surface of the bolt. I like the cratex rod tools in a drill press. The jig holds the bolt in such a manner that it can be indexed front to back and back to front an amount equal to roughly half the diameter of the tool turning the swirls. Likewise it allows indexing the bolt around it's axis as the line of swirls are completed.. One should start with the row that won't show as the bolt is opened and closed. The swirls easily seen must be even and contiguous. If the bolt is flat such as the Ruger 10/22 it may be moved up and down manually with the jig providing left-right control.
gunnut69--
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