Breaking in (or seasoning) a new barrel

[Daryl]

I am making arrangements to purchase the Mike Davis-built .40 SMR that was listed on the trader forum recently.   It is a Colerain A-weight.

I looked on Colerain's website, but I don't see any mention of post-production lapping or polishing of the bores.   Their website indicates that .40 caliber barrels have grooves .012" deep and a 1:48 twist (which evidently is an ideal twist rate, though I would have expected something closer to 1:60).

Is there anything special I should do initially, or just load and shoot it?   

Really looking forward to it!

1 turn in 38" is normal up to .40 cal.

Load it and shoot it.

I used a .395" RB Lyman mould to start with- but also tried a .400".  I used 10 ounce denim that mic's .0220" to .0225" in thickness, compressed using calipers.  Both sized balls loaded easily and shot splendidly.

[Smoketown]

Okay, so I had a chance to shoot the Colerain barrel.   I was using .395" Hornady with both .010 and .015 patches.  I could tell that the patch/ball combo was too loose, as after starting the ball went down very easily.   

Even with .015 pillow ticking, total ball plus patch diameter would be .425".... uncompressed.   Assuming a correct .40" bore, and Colerain advertises .012 grooves, the total would be .424".   

I think the loose patch/ball fit would make for poor accuracy (I wasn't particularly shooting for groups), but I think it also caused a good bit of fouling to build up.

I may just order some thicker pillow ticking and cut patches myself.   Any good suggestions on where to buy it?

Bones,

Try some DENIM and take your calipers to the fabric store.   

Another option is putting a cigarette rolling paper or two (or more) over the patch then the ball until you get the fit/accuracy you are looking for.

Measure the total thickness of the resultant 'patching' and buy material of the same thickness.

Cheers,
Smoketown

[rfd]

for a brandy new barrel, i'll degrease with some moose milk, swab out with dry patches and examine them for tears, pulls or other aberrations that might signal barrel rough spots or issues.  other than that, begin the test loads and shooting.   

it may seem anal to some folks, but i also like to know that any components threaded into the barrel are anti-seize lubed.  this is typically normal procedure for onshore gunmakers, but it's good to check with its creator anyway.  not so for all offshore production guns.  a/s lubed threads will better fight off the migration of bp residue and allow the parts to be removed if need be at a much later date.  just something to think about, perhaps.