Breaking in an M70 Winchester .375 H&H barrel

[Hornedfrogbbq]

So what is everyone's thoughts/process to break in a new barrel? Do you believe in it at all or do you go shoot and clean like you will after 3 years of hard hunting. Does it depend on the barrel, manufacturer, etc.? What bullets do you shoot to "break-in" the barrel? Cleaning frequency?

 

[PARA45]

I shoot and own several Weatherby calibers, and some are barrel burners. The 375 H&H is not a barrel burner, like the Weatherby are. This is what I do with any of my rifles. I never let the barrel get too hot. If this is a new rifle, I shoot one round per every 2-3 minutes. Never shoot more than 10 rounds in one session, and when I get home, I clean the barrel really good with Boretech Eliminator. Haven't had any issues yet.

Someone a while back told me that more barrels are damaged by improper cleaning than by shooting them.

 

[deewayne2003]

First thing I do is clean the packing grease/oil out of the barrel and action with solvent and brush.

I take a bore snake to the range with me and wet it down with solvent and pull it through after every shot for the first 4-5 shots; then pull it through after every 3 shot group during the sight in process and then I consider it broken in.

Larrywillis.com has different break in procedures listed depending on the type of barrel.
https://www.larrywillis.com/

 

[375Fox]

I’m not a target shooter. I can’t say I’ve given it that much thought. If I shoot a rifle at the range I will run a brush and couple of oily patches through before putting it in the safe. I’d do that whether new or old. 100 rounds on a new to me rifle gives me a level of confidence I need to hunt, but I typically don’t exceed 5 rounds a day at the range though. Aside from 223 I’ve never had any accuracy or cleaning issues with rifles.

 

[One Day...]

As deewayne2003 indicated it is CRITICAL to clean a brand new barrel after you purchase the rifle. They are typically coated in a light type of cosmoline that will not move ahead of a bullet when fired but may create micro-bulges if not removed.

Typical solvents will do the job. You will get a number of dirty patches out of a factory-new bore...

After that, barrel breaking may (?) work for competitive bench shooters but I have found it an utter waste of time myself. Just go and shoot.

More good barrels are damaged by over-cleaning (do not use a steel rod !!! insert the rod from the chamber side !!!) than they are by non-cleaning. But avoid rust if applicable with light oiling (and remove the oil before shooting again) and above all, as PARA45 said, do NOT shoot long strings. If the barrel is getting uncomfortably hot to touch, let it cool. Stop shooting way before the barrel is too hot to leave your hand on for several seconds.

In term of maintenance, I used to lightly oil the barrels when I lived on the humid east coast, but now that I am in Arizona, or when I am in Africa, all I do is just pull a boresnake through the barrel (do not rub the string on the edge of the crown) at the end of the day, even if I did not shoot that day, to remove powder residues or dust.

I shoot TTSX in my Blaser barrels and various other rifles, and I find that it typically takes more than 150 shots to start loosing 1 MOA accuracy. This is when I clean them. Admittedly, some older barrels may have rough bores and may loose accuracy in as few as 50 rounds or so, but CNC modern production barrels are generally quite smooth.

 

[HookMeUpII]

My feelings are, if I am spending that much on a rifle I might as well break it in. I have a buddy who is the sniper on the local SWAT team that doesn't believe at all in breaking in barrels. Think about that one for a second lol. Is he wrong? I can't say.

The only ammo I would not use is anything unjacketed. Which you probably can't even find anyways. The idea is to seal/smooth out the micro-fissures and rough spots in the rifling. Only copper can do that. Also, if you can, use maybe a touch better ammo. I wouldn't break in with $100+ a box Barnes. For example, I broke my last 300WM in with Sellier & Bellot which is notoriously dirty ammo. You'll spend a lot of extra time getting powder fouling out of the barrel. Remington is decent break in ammo.

Winchester, being owned by Browning, is probably adopting their method.

Pre-clean the rifle at home, before first shot, to get all the packing grease/oil off and out.
10 rounds - cleaning after every round.
10 rounds - cleaning after every other round.

However, check the manual. They usually put it right in there.

I use Bore Tech stuff which is pricey but I like it. The cleaning process I use for breaking in:

- Wet patch
- Wet bore brush
- Wet patch
- Dry bore brush
- Wet patches, until mostly clean
- 2-3 dry patches to dry

It's definitely tedious. Not my favorite thing to do.

I can't fault people who don't believe in it. I am in the camp of those who do believe in it.

Oh and definitely use a bore/patch guide.

 

[uplander01]

I never touch the inside of a bore with a brush, and I don't believe in barrel break in. I use only Wipe Out brand Foaming Bore Cleaner and the Accelerator wet patches (2) before I foam the barrel. Clean new barrel with that, go shoot. I use a keg hose from the chamber end so your chamber is immaculately clean as well, a standard plumbing keg hose will slide right in and seal for most all magnum calibers. I generally never shoot more than 20-30 rounds a session, never let things get too hot, maybe 5 round groups tops, set the gun up vertical with bolt open and let the heat rise out of the barrel, when cool again start shooting.

 

[rdog]

I have proven to my self that if you break in a bbl it will clean easier through out its life. its a pain in the arse to do but worth it . clean it real good before 1st firing then, 1 shot & clean 2 shots & clean ect up to 10 shots do not let it get hot use a good solvent like boretech eliminator... also clean out the chamber of any solvent. its worth the effort. Use a bore guide & a nylon brush. & an alloy jag so you can see any blue copper on the patch. I believe that copper bullets leave more copper deposits in bbl than normal cup & core bullets so do not use them for bbl break in.