barrel break in....

[chucksniper]

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?

 

[watercam]

Around 200 in my barrel,s).

 

[butchlambert]

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.
Butch

 

[chucksniper]

Thanks Butch.... It was lapped at McGowens shop. I give it a go with JB'S Paste though.

 

[Jeff Peinhardt]

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?

 

[chucksniper]

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?

 

[Steve Blair]

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.

 

[butchlambert]

sleepygator,
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.
Butch

 

[Steve Blair]

Butch, it was the same one that recommended your tension screws for my Farley rest.

Seriously: I owned two .244 Remingtons with 12' twist, the first a 722 and the second a 40-X. Neither would shoot anything but a flatbase >75 grains at longer ranges. Both would group well at 100 yards but groups, expressed in moa, would open significantly at 300 yards or more. All the bullets he mentioned were boattails and my experience is that a 12' twist will not stabilize them in that weight range. The longer the bullet, the more that gyroscopic precession is likely to play a determining role in bullet stability. My 6mm rifles also had a notable ballistic advantage over the smaller .243.

More recently, I had a great 95 Sierra MK load at 3250 from a 9' twist 40-X 6mm Remington that shot very well at 95-100 degrees when developed, shot 50% keyholes at 550 yards at 40f, indicating marginal stability.

It is entirely possible that my anecdotal experience is atypical and yours more likely. I obviously know who you are and respect your opinion but Chucksniper's description fit well with what I have experienced. The increasing gyroscopic precession effect is why some folks discourage group shooting at 100 yards as an accuracy measure.

I sometimes shoot in cold temperatures, particularly when calling coyotes. Our local mountains in San Diego reach 7000 feet and it gets nippy up there. A typical shot is 400-500 yards. Those conditions encourage using boattails and paying attention to long-range stability. I have heard rumors that it very occasionally gets below 70f in Texas but that it is a rare occurrence and probably a Yankee trick.

BTW, the tensioners work well, providing overall better feel and more predictable adjustment. I attribute that to the linear characteristics of bellevilles. You know I read that in a book.

 

[chino1969]

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.
Butch

Butch,
I no longer break in match grade barrels and have not seen any difference in fouling or group size. I monitor every barrel, with a borescope, when it is brand new, after chambering, after initial rounds and after cleaning. I do use JB in the throat area but thats about it. People get way too caught up in the break in process.

Lou Baccino

 

[alf]

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.
Butch

Butch,
I no longer break in match grade barrels and have not seen any difference in fouling or group size. I monitor every barrel, with a borescope, when it is brand new, after chambering, after initial rounds and after cleaning. I do use JB in the throat area but thats about it. People get way too caught up in the break in process.

Lou Baccino

I quit breaking in barrels myself and do the exact same thing.

A borescope is a great enlightener......

 

[butchlambert]

sleepygator,
We have to do what works for each of us. I do not shoot over 300yds and can't comment on that. I had a friend in Australia loose his belleville washers and used viton o'rings. Said he liked the feel. I feel the larger surface area of the buttons allow less psi pressure on the sliding plate to get the feel. Who knows!
Butch