Your thoughts on "barrel break in"?

[GrapeApe]

Mine's pretty simple, and based on my experience. A brand new barrel is probably going to to need a few rounds through it, and a few thorough cleanings before it shoots its best.
What I DON'T agree with is the whole, "You MUST shoot 1 round and clean for the first 5 shots, then 5 rounds and clean... blah blah blah"

Case in point, The Rosco Purebred medium contour 20" 1:7" barrel I bought last year. First outing w/ IMI Razr Core 77gr 1.25" 5 shot group to start, and every subsequent group with any ammo was worse than the previous. IIRC fired a total of 15-20 rounds through it that outing.
Looking back, I noted that cleaning it after that outing was akin to "copper mining" with multiple flakes of visible copper on the patches.

Swapped rings and took it back to the range to resight it in, and other than 1 called flier after a scope adjustment, put 9/10 of the same lot# of the IMI in to 1.25". Also noted that there wasn't not nearly as much copper after cleaning.

Took it one more time, and the first 5 of the same lot# of IMI yielded a 0.329" group.

So YES, I do believe that a brand new barrel will "break-in" over time, it's the whole, "You must follow this exact recipe to break in a barrel" that I disagree with/

Your thoughts?

[Justsomedude]

Absolutely. Especially barrels with rifling that was cut are going to have burrs that will catch the copper but at the same time the copper will wear those burrs. It just makes sense to clean in between shots to speed up the process and refine it a bit more. In essence you're using the bullets to polish the bore.

[CPJ 2.0]

You can’t prove it works or doesn’t, or makes things smoother faster.

Why?

No two barrels are exactly the same.

And you can’t undo the process that you did to the barrel.

But, it’s something to argue about.

[GrapeApe]

My thing is, ANY shooting and cleaning is "breaking it in"
the YOU MUST... recipe is what I disagree with

[CPJ 2.0]

You must is horse poop. Just like you will ruin your barrel if you don’t do it is horse poop.

[GrapeApe]

You must is horse poop. Just like you will ruin your barrel if you don’t do it is horse poop.

100% agree
Shoot it and clean it like you normally do, go forth and enjoy life

[Varmintmist]

Pretty sure this was settled years ago on the forum.

You must shoot one then clean with virgin hair and unicorn spit followed by dancing 3 revolutions clockwise while naked juggling chipmunks in kilts in a counterclockwise direction under a full moon and sipping a PBR for the first 30 shots of a barrels life

[CPJ 2.0]

Kilts (skirts, let’s be honest) we’re never involved. It was a loincloth.
Get it right.

[Buford]

Never gave it much thought.

[Varmintmist]

Kilts (skirts, let’s be honest) we’re never involved. It was a loincloth.
Get it right.

Loincloths on the chipmunks? Its been a while, or was it kilts just in the upside down land of AU?

[CPJ 2.0]

Loincloths are on the dudes. Chipmunks don’t wear clothes. So, that’s kinda silly. There’s no skirts or kilts involved.

[Gila]

Is barrel break-in different for a .270?

[Wambli Ska]

Loincloths are on the dudes. Chipmunks don’t wear clothes. So, that’s kinda silly. There’s no skirts or kilts involved.

This! It was loincloths!!! Case closed.

[Jayhawker]

Same answer as when we discussed this a decade or so ago..
Just shoot the damn thing

[Castle]

I remember it being loincloths also and cat juggling.

[Bigslug]

One thing I've learned definitively with cast bullets is that part of keeping your barrel from turning into a lead mine is to give the bullet a tight, but smooth, uninterrupted path to the muzzle. If there's a path for hot gas to get around the side of the bullet, it will vaporize the surface and that lead will plate on the bore. Copper's going to behave the same way - albeit at a higher melt point.

So, if you have burrs or constrictions, those will either score the surface of the bullet or reduce it's diameter below nominal, giving that hot gas a path around the bullet.

If it's a factory, mass-appeal rifle, I pretty much have doubts about those who made it. . .so I juggle the chipmunks and break in the barrel to buff out the rough spots.

If it's a custom rifle using a high-end, lapped barrel blank, the final gunsmith still had to run a chambering reamer, and I assume rough spots remain in the critical leade of the rifling. . .so I juggle the chipmunks and break in the barrel to buff out the rough spots.

The goal is a barrel that - once done - shoots well and you won't have to clean, ever, unless you are dealing with corrosive propellants, a humid environment, or long-term storage. It takes about 20 rounds of jacketed, which doesn't need to be good stuff, and you can dink around with your scope settings to get it close while you go through the process. Not much to spend and much to gain - so I juggle the chipmunks.

[Varmintmist]

Loincloths are on the dudes. Chipmunks don’t wear clothes. So, that’s kinda silly. There’s no skirts or kilts involved.

This! It was loincloths!!! Case closed.

Cats and loincloths for barrel break in. Nekkid and chipmunks for cleaning muzzle loaders. Had my witchcraft streams crossed.

[PFD45]

What ever happened to those bullets (components) that were coated with progressively finer abrasives.

I think they were sold as "fire lapping" or something like that.

Sold by G. David Tubb if I recall.

They looked like a good idea but seems to have fizzled out.

[Zee]

I clean a new barrel.
Then I lap the new barrel using diatomaceous earth.
Then I shoot the new barrel.
Then……clean as needed for the rest of its life.

[Linefinder]

Take your new barrel out over a good pdog town at 8AM. By 8:30ish or so.....it's broke in.

Mike

[Zee]

Ha!

[Ernie]

Take your new barrel out over a good pdog town at 8AM. By 8:30ish or so.....it's broke in.

Mike

Depending on the cartridge, you can start cooking a barrel in that time frame

[JunkCollector]

Take your new barrel out over a good pdog town at 8AM. By 8:30ish or so.....it's broke in.

Mike

That sounds better than browning the barrel any day.

[Wambli Ska]

So seriously, clean. Shoot. If accuracy is acceptable out of the box leave well enough be. It will get better in its own. If not, start troubleshooting process which might include polishing the bore.

[Bigslug]

What ever happened to those bullets (components) that were coated with progressively finer abrasives.

I think they were sold as "fire lapping" or something like that.

Sold by G. David Tubb if I recall.

They looked like a good idea but seems to have fizzled out.

It is still a thing for revolvers at least.

The kit sold by Veral Smith of LBT consisted of two stiff steel plates between which you would roll your lead bullets to impregnate them with lapping compound. Since there's no bullet lube present, only light charges of fast-burning powders barely sufficient to get the bullet clear of the muzzle are used. Should also work with jacketed in rifle barrels, but I don't know how hot Tubb was loading to accomplish this.

The primary use for the LBT process is to lap out the .001" to .002" of "frame crush" common to a lot of revolvers. Basically, if your .357's barrel has a .357" nominal groove diameter, the factory's act of tightly screwing it into the frame compresses that down to .355"-.356" at the frame juncture. That's enough to swage your bullets down below what the rest of the barrel wants, allowing the gas blow-by and lead fouling I discussed in my first post.

I've also used the process to uniform revolver's cylinder throats while attending to the frame crush problem - if one or two cylinder throats pin-gauge smaller than the others, I only shoot the lapping round through those holes until they all gauge out the same.

With regards to barrel "break in", the process would polish up the barrel surface, but it would also create a VERY minute tapering of the bore. The lapping compound will be doing most of its work toward the chamber end of the barrel, so the fit of the bullet will become tighter closer to the muzzle. This would counteract some of the damage incurred by the passage down the bore and help to maintain the bullet's sealing against gas blow-by.

Larry Gibson is some of the higher level brain power over at the Cast Bullets. One phenomenon he's witnessed on cast rifle bullets he's been able to recover without damage is that they've somehow gotten swaged down a thousandth or so BELOW the barrel's groove diameter. The operating theory - and probably the only plausible answer - is that the wax/grease bullet lubes are being forced out of the lube grooves by the rifling's compression and forming a boundary layer between bullet and barrel, acting as an ablative gasket for the duration of the bullet's time in the tube.

With that light shining on the the forces involved, the advantages of having a smooth, uniform, slightly tapering bore become a little clearer.

The deliberate lapping of rifle barrels that I've done is a little more "old world": a cleaning brush is spun carefully against a grinding wheel to shorten the bristles on it's front end, giving it a bit of a "Christmas tree" conical shape. This is then run forward from the breech to within about 3" of the muzzle. That 3" is then filled with molten lead, which adheres to the brush. The lead plug is allowed to solidify and is then pushed forward so the puddle that formed on the muzzle can be clipped off. The plug is then coated with fine grit compound and passed carefully through the bore a number of times. Depending on what's needed, the process can be repeated, or a progression of grits can be used.