Breaking in a new barrel

Black Diamond 408

Well-Known Member
Sep 6, 2003
OK guys, I'm taking a poll here and wandering how you'all break in your new bbls. I have told several customers on what they should do, but they never do! My last customer, bought a 408 c-t from me and he is having trouble getting it to group. After checking everything over several times i have found nothing loose. So i asked him on how he has been cleaning it. He said: after 25 shots or more(YIKES)with a electronic cleaner system. Do they work to good or remove to much of the fouling exposing raw bbl? I dont think the bbl has ever been broken in. After I shot the 408 and cleaned it with butches, took it back to the range and it shot very well, not a flyer on the target, a 7shot group was in one big ragged hole.

Thanks to all who respond.


Well-Known Member
Aug 31, 2002
in front of my computer
Read and ALWAYS fallow the recomendations of the barrel MFG.
Be fore the first shot CLEAN with Jb Bore paste 25 strokes at least. then wipe out with wipe out two patches of Kroil down the barrel and let it sit over night, bry barrel with patch before shooting and dry the chamber before each shot. Make shure the patch comes out clean.
After One shot, clean with JB bore past then wipe out, then two patches of kroil applied let it set 15 min then dry patched dry un till there is NOthing on the patch.
After Shot 2 I used sweats as derected. Then Ran two patches of kroil down the barrel let it set 15 min, then a dry patched the barrel till dry and the patch came out perfictly clean.
After Shot 3 , Same as one.
After shot 4, same as two.
After shot 5 same as two.
Shoot a 3 shot group and clean same as shot 2.
Shoot a 5 shot group and clean with a copper solvent and the apply a light coat of gun oil. This is the way I did it. The barrel should be broken in and ready to shoot a 10 shot string. This takes all day but i believe time invested early pays off later. I hope this helps.

[ 09-25-2003: Message edited by: baldeagle713 ]

[ 09-25-2003: Message edited by: baldeagle713 ]

[ 09-25-2003: Message edited by: baldeagle713 ]

[ 09-25-2003: Message edited by: baldeagle713 ]


Well-Known Member
Jul 30, 2003
Bountiful, Utah
Breaking in a barrel is as individual as you can get. What you do depends as much on the person as it does in the barrel.

Basic rules:

If it's fouling and the accuracy is dropping off - clean it.

If it's a new barrel expect to have to clean it more often.

If it's a standard factory barrel expect it to take longer to break it in.

If it's taking a long time to break in, run a bore scope down the barrel to check for something major, and fire lap it if needed. Hand lapping is better, but it's hard to find someone that does enough of them a month to call them experienced.

Expect it to take anywhere from 10 to 300 rounds to break it in. I'm over 150 rounds on mine and I'm going to use Tubb's Final Finish to lap it. The last half of the barrel is "very rough" according to the bore scope and my 'smith.

Mark in Utah

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