Varmint Al's barrel break-in method

[Ackley Man]

I'm sure it would be pretty much impossible to prove that any aspect of barrels are saved with break-in.
After all, our barrels don't wear out. They burn out.

Someone shooting a 6PPC at 75Kpsi needs to settle a barrel, and determine if good enough to go forward with it -fast as possible.
I believe that's what it comes down to with Tony's notions in this regard.

I've never heard of a 6PPC at 75K psi. 39,400 to 42,700 is about the average range. Most actions have a max of 65K.

 

[Radman]

So, I have a bunch of spare time on my hands at the moment. During a mindless wander of the Internet, I came across Varmint Al's page. Had been a long time since I had first visited it. I read his barrel break-in procedure and thought I would post it.

NEW BARREL BREAK IN.... There is so much black magic out there about breaking in a barrel, that I am not going to suggest any procedure. I will merely tell you what I do with a new barrel. I take the brand new barrel and use J-B on it. That's right, I clean and polish it with J-B before even firing the first round through it. I put a light coat of J-B on a patch and give the barrel about 50 strokes from end to end with it. Then I clean the J-B out with a couple of patches of Shooter's Choice MC#7. I dry the bore with 3 or 4 patches until it is completely dry. I carefully clean the chamber of J-B too. That's it, the barrel is broken in and I am ready to sight in, shoot some groups, and work up an accurate load.

What do you think?

I've never "broken-in a barrel" in my 55 years of shooting. I'll usually swab out the factory gook with 1 oily patch, shoot it any number of times, take it home & clean it. My barrels give me great accuracy & seem to last as long as I need them. My 1 rule? Don't heat them up! Has worked for me on 20 new rifles.

 

[sturner]

Barrel makers love break in procedures it sells them more barrels
JMO

 

[zr600]

I was told for my muller works carbon wrapped barrel to just shoot it, clean it, shoot it clean it. Then once find a load shoot it till accuracy falls off. I basically loaded up 10 shoots for my first range trip, went to 25 yards got the scope close, went to a 100 yards got it within an moa of the bullseye. Then attached the megneto speed and run a Satterlee method ladder test. Got home cleaned it. In this method I found a load that shoots less then 1/4 moa. Only have 40 rounds down barrel now and have cleaned it 3 times I think. This is on a 22-243ai so I will clean carbon out every 30-50 rounds. I let my old barrel in the caliper go till accuracy fell off and it was a pain in the rear end to get clean. My last few barrels I did some sort of shot 1 clean, shoot 3 clean. After this barrel I'm done doing that. Just wasting rounds and cleaning supplies doing that way I think. I have the rest of my brass loaded up to fire form then I will run a latter test again with the fire formed brass. And call the barrel broke in.

 

[Mikecr]

I've never heard of a 6PPC at 75K psi. 39,400 to 42,700 is about the average range. Most actions have a max of 65K.

You're way wrong about that.
A good while ago I polled Benchrest Central(when it was booming) about accurate 6PPC barrel life, brass life, and loads. I had hundreds respond with incredible consistency. 'Competitive' were absolutely around 75Kpsi. Below this was not producing that considered competitive.
Of course that is not viable in anything, including a tiny 6PPC, so their cases did not last but 4-5 shots, and their barrels were lucky to shoot good enough beyond 900 rounds. Just the price of being competitive.

This is the typical load and accurate barrel life of a competitive 6PPC:

And an action barely feels the forces of a 6PPC, as it's area is so small. There is not a safety concern here regardless of action.

 

[ntsqd]

A highly polished bore would have too much bearing area and create a huge amount of friction. Same is true for an incredibly rough bore finish. It seems to me that there's some sort of sweet spot in bore finish where it's just rough enough to not cause a lot of friction ('the bore sped up") and not so rough that it has a lot of friction and fouls easily. I'm sure that this ideal surface roughness range is quantifiable. I'm also sure that the top tier barrel makers have put a lot of thought and effort into identifying that range and how to achieve it, and for some achieving that may require following their "break-in" procedure. The maker who says "just shoot it" has likely refined their procedures to the point where no "break-in" is needed as the final step in making the barrel.

Two barrels made by different people, on the same machine, are going to be different. It may be subtle and it may not, but different they will be. I suspect that systems like the Tubbs remove those nuanced differences in bore finish and substitutes it's own. If you shoot as often as David Tubbs does (or did?) then consistency from one barrel to the next is an important consideration. Having a consistent method for achieving that bore finish uniformly would be huge in a game where you go through barrels at a high rate.

 

[Mikecr]

I'm sure that this ideal surface roughness range is quantifiable.

I believe the term you're looking for is surface profile. Difficult to measure inside a bore, but it can be done, and easy with an outside sample.
You are right about a magic range there, and that the best barrel makers lap to it.

With bad barrels in the past I became super sensitive to copper fouling. With this, I've messed with different resolutions and learned enough about coatings, lapping, fire lapping, polishing, and barrel cleaning in general.
Two learnings that helped for sure: (-) Never polish a bore, and (+) Tubb's fire lapping matches that of the best barrels.
One takes you out of range, the other takes you in.

 

[ntsqd]

"Surface Profile" is the correct term, but that is not a commonly used term even inside of most machine shops. Those that I work with tend to use "surface finish." I chose "roughness" in the hope that it would be better understood by a larger audience.

 

[QuietTexan]

ASME calls it "surface texture" in their standard I've dealt with in machining engines but never considered re: the inside of a bore.

Same is true for an incredibly rough bore finish.

Button rifled barrels would have terrible Ra or RMS numbers because of the transverse valleys in the grooves, and throats could never be measured because of the gator skin that forms pretty quickly in some cases - but barrels with both issues can still shoot fine. Would be very hard to quantify because the tools I've used wouldn't work on either of those cases. Maybe there's a better way to measure a sectioned barrel though.

 

[budlight]

Castrol chrome polish is super fine abrasive. I'm kind of a SS barrel person. I put the chrome polish on a bore snake and run lots of pulls each direction to polish out the barrel.

For years I was into home made coating bullets and I had some very short life rifles like a 30-378. I would like to think that polishing the barrel and breaking in the barrel with moly coated bullets actually extended the barrel life a little. It seems to me that I get very little copper out of the barrels after shooting moly dry powder tumbling bullets. Mostly black. moly bullets are so slick that they lose velocity. you have to add a couple of grains of powder to run the same FPS as it's copper counter part

 

[ntsqd]

There is such a thing as a "Stylus Type Profilometer." Never used any type, so no idea how effective one would be in measuring the surface roughness/finish/profile of a barrel bore.

 

[Mikecr]

I would like to think that polishing the barrel and breaking in the barrel with moly coated bullets actually extended the barrel life a little. It seems to me that I get very little copper out of the barrels after shooting moly dry powder tumbling bullets. Mostly black. moly bullets are so slick that they lose velocity. you have to add a couple of grains of powder to run the same FPS as it's copper counter part

Moly does extend accurate barrel life -if managed. That management includes extended cleaning intervals with abrading it back to baseline. Otherwise, moly will reduce accuracy, and accurate barrel life overall, because it sticks to itself (wiping), causing constriction. That's it's disadvantage.
It does not reduce erosion nor velocity, because it's slippery. Moly in particular reduces heat/pressure as it vaporizes. Latent heat.
That's a benefit and what causes lowered velocities.
Moly, like most other coatings reduces copper fouling, as the loose copper doesn't stick to it well.

So for your goal of improving barrel life, with use of moly, I can see why you would conclude that polishing a bore is a good thing.
But for those of of us concerned about copper, polishing is bad and never good.

A better coating is tungsten disulfide (WS2). It is a universal fouling, that reduces copper, and cleans out well enough without use of abrasives.
While way slipperier than moly, WS2 does not affect velocities/pressure. It also does not affect accurate barrel life one way or the other.
It cuts copper fouling by ~1/2.
I dry pre-foul every gun barrel(long & short) I have with it, after cleaning. This, so my first shots are always on the money.
That's a big benefit for me.

 

[baldhunter]

I've noticed my rifles that I've taken the time to do the shoot,clean,shoot,clean the first ten rounds,then after every three for the next twenty one rounds,will shoot the first cold bore shot in the same group,clean or dirty.Was it the break-in?No way to prove it was,but I've had rifles that I didn't do the break-in and they always required a couple of fouling shots to get them back in the group after a barrel cleaning.Maybe I'm just lucky,but if it helps the first cold bore shot,I'll take the time to do it.

 

[LDHunter]

I've noticed my rifles that I've taken the time to do the shoot,clean,shoot,clean the first ten rounds,then after every three for the next twenty one rounds,will shoot the first cold bore shot in the same group,clean or dirty.Was it the break-in?No way to prove it was,but I've had rifles that I didn't do the break-in and they always required a couple of fouling shots to get them back in the group after a barrel cleaning.Maybe I'm just lucky,but if it helps the first cold bore shot,I'll take the time to do it.

I've used the same system for over 20 years with the same results.