Reply with quote #1
I just ran 80 rounds througha McGowen .243 varmint barrel with a 1:12 twist.
After initial break in, how many rounds, on average, does it take for a barrel to shine in accuracy?
Reply with quote #2
Around 200 in my barrel(s).
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Every round you use breaking in a barrel is less that you will be using it. Either get a lapped barrel or pay to have it lapped. The only thing you will then be breaking in is the tool marks in the throat from reaming. Use JB paste on the throat every 10 rounds for about 100 rounds.
I go out and shoot groups. Mine either shoot or they don't.
Reply with quote #4
Thanks Butch.... It was lapped at McGowens shop. I give it a go with JB'S Paste though.
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If its going to shoot you will see it in the first 25-40 rounds. With proven bullets, primers, powders you should see good stuff with the first 3 shot groups! I have 10 Kreiger barrels and some Bartlein's and some are definitely better than others.... you can see it quick!
Be sure to shoot some wind....some barrels really "work" in the wind. Those are the ones I desire. Anybody have some of these?
Reply with quote #6
I wish I could post my targets. So far Nosler 70 bt, Sierra 85 grain BTHP, Sierra 80 BTSP. At 100 yards I had .25 inch groups, the first two rounds, with a cold barrel, were in the same hole. The best round was the 80 BTSP as far as 300 yards. It spread to 2", that's with a compressed load. Any suggestions to tighten up the 2" group?
Reply with quote #7
All of those bullets are marginal in a 12" twist at .243 velocities. That is a varmint twist in 6mm and you should shoot bullets in the 55-65 grain range. If the 65 Hornady V-Max is driven above 3500 fps, it should be good down to about 70f. Below that, stability will deteriorate.
Remember, the 12" twist is what killed the .224 Remington vs. the .243 Winchester's typical 10" twist. The .244 could not stabilize heavier bullets while the .243 could. My 6mm Remington with 9" twist can handle bullets up to 90 grains but I cannot get the 95 grain bullets to group at longer ranges. As long as you stick to light bullets, the barrel should shoot well.
BTW, my 6mm shoots the 58g Hornady V-Max extremely well. 48g Varget gives me 4050 fps with ES <10 and SD <4. Groups stay under .5 moa at 300. I have shot a couple .75" 5-shot groups at 300. You should see what this load does to a crow.
Reply with quote #8
What book did you read? We use 14 and 15 twist for 68grn. bullets.
I shoot 80grn bullets in a 12 twist all the time.