Bolt gun “break-in”

[Grouchy Bear]

[JackEllis]

My break-in procedure for a new rifle is to shoot a bunch through and then go clean it.

The one thing I avoid is allowing the barrel to so hot I can't comfortably touch it.

[vintagearms]

My break in is simple. Run a patch or two through it before going to the range, just to clean out any gunk from the factory. Go shoot 50 slow fired rounds. Clean it, then on your next trip, wait to clean until the groups open up, which can vary but typically 200-400 rounds.
Get a good solid cleaning rod and jig. (I use the Boretech proof positive ones)
Also, get a bore guide.

[LynnJr]

For 99% of the posters here a barrel break-in serves no purpose.
The other 1% no why it's done.
For the curious who want to know what that 1% is up to here goes.
When the reamer is run into a custom barrel it leaves little lines that run perpendicular to the bore just in front of the throat of the barrel.
When you fire the rifle the burning powder lays down carbon fouling and it takes up to a hundred rounds before those scratches get burnished away.
If you clean between shots the burning gases work faster on removing those scratches.
It does nothing on a factory barrel because they are so bad it doesn't matter what you do.
A borescope helps a lot.
Aftermarket barrels are lapped in the same direction the bullet travels and are very smooth.

[sigstroker]

So you break-in hand lapped barrels? I've seen some people say they don't and just shoot as is.

Is that unique to your style of (big boomer) shooting, or would you say it applies to all cartridges?

[sd joe]

Just shoot it.

[LynnJr]

Sigstroker
The guys who shoot the 6 ppc competitively use the same reamer and get 10-20 barrels done at the same time. When they go to the range they will use 54-57 clicks on a Harell's powder thrower and N133.
They will know in 30 shots wether the barrel is competitive or just a club match or practice barrel and after 800 rounds they get used for muzzlebrakes or escutcheons.
They don't want to use up precious barrel life but they all clean and they clean very often.

[sigstroker]

Okay, but I was asking about break-in, in response to your post about break-in.

[1859sharps]

the whole break in idea is based on superstitious learning based on an assumed cause and effect. "shot better because I did x"...but how do you know you wouldn't have shot just as good had you not done X?

[Jesse 2]

For 99% of the posters here a barrel break-in serves no purpose.

The other 1% no why it's done.

For the curious who want to know what that 1% is up to here goes.

When the reamer is run into a custom barrel it leaves little lines that run perpendicular to the bore just in front of the throat of the barrel.

When you fire the rifle the burning powder lays down carbon fouling and it takes up to a hundred rounds before those scratches get burnished away.

If you clean between shots the burning gases work faster on removing those scratches.

It does nothing on a factory barrel because they are so bad it doesn't matter what you do.

A borescope helps a lot.

Aftermarket barrels are lapped in the same direction the bullet travels and are very smooth.

This is free bore area picture from a relatively new Tikka 6.5CM (500 rounds). Are these lines reamer marks? They disappear after throat. Pretty nasty. Still shoot well.

[longrange1]

This is free bore area picture from a relatively new Tikka 6.5CM (500 rounds). Are these lines reamer marks? They disappear after throat. Pretty nasty. Still shoot well.

yes....the circular marks going the opposite way the bullet travels are from the reamer and are what your trying to eliminate with barrel break in.

the problem with most factory guns is that the throats look like your tikka and you would most likely shoot that barrel out trying to get that throat smoothed out.

[longrange1]

So you break-in hand lapped barrels? I've seen some people say they don't and just shoot as is.

Is that unique to your style of (big boomer) shooting, or would you say it applies to all cartridges?

yes but barrel break in is really the wrong wording...your trying to smooth out the reamer marks in the throat not break in the barrel.

ive done the full shoot one clean shoot 3 clean shoot 5 clean ECT for 50 rounds on a factory savage 300wm and it was a complete waste of time...this barrel was very accurate until it hit 45-50 rounds then it started to open up and i mean from 1 hole to 2" and 3" groups then it was MF'R to clean.

i have not shot a factory barrel sense and that was over 30 barrels(16 yrs)ago but i do do a break in on every barrel...i have my own reamers and i have a great smith.

i shoot 1 then clean...most every barrel has taken 2-3 rounds to stop the heavier fouling with a couple barrels taking 5....i then shoot 10 rounds fast fire let cool then clean and im done.

[longrange1]

the whole break in idea is based on superstitious learning based on an assumed cause and effect. "shot better because I did x"...but how do you know you wouldn't have shot just as good had you not done X?

maybe with a factory barrel but the benchrest shooters do a break in for a reason and its not "superstitious learning based on an assumed cause and effect" its based on group size on a target at 1000yds.

[LynnJr]

On factory barrels with factory reamer specs the throat is huge compared to a competition gun reamed with a custom reamer.
If the bullet starts out with the same amount of yaw on both barrels you will get more fouling on the custom reamer barrel because it is scraped harder on to those circular ridges caused by the pilot on the reamer.
Barrel break in has nothing at all to do with accuracy it just helps you get to your barrels potential quicker.

If you guys are shooting the newer accuracy chamberings like the Creedmoor and PRC the throat area on those reamers has been tightened up by the factories to help start the bullets out straighter. When you rebarrel one of those chamberings with a custom barrel breaking it in will get you to your peak potential around 100 rounds sooner.
If you ever experienced the same load causing pressure issues and you can't explain it try cleaning out the throat area as fouling will build up on those circular marks caused by the reamer pilot.
For 99% of the shooters you will never notice anything cleaned verses uncleaned and with factory barrels it's a complete waste of time.
With the factory's trying to gain a market edge by producing more and more accuracy cleaner barrels will soon gain some popularity again.
With a lot of shooters going bigger and bigger for the ELR type matches and the cost of those bigger longer barrels and there shorter usable life break in can be done while working up your load so it's a no brainier as you have nothing to loose by doing it.
For a casual shooter you will do more harm than good from not cleaning properly so again avoid it.
On Calguns there are probably 10 posters here that it will help.

[1859sharps]

maybe with a factory barrel but the benchrest shooters do a break in for a reason and its not "superstitious learning based on an assumed cause and effect" its based on group size on a target at 1000yds.

Actually if i was a benchrest shooter, I go out and buy the best rifle, assembled from the best parts available, and by the best smith in the world...do a barrel break in because that is what benchies do, then point to my group size at 1000 yards as proof it works.... that is very definition of superstitious learning.

If on the other hand I buy 20 rifles, plan out a way to have them build as close to identical as is possible. then take 10 of them, use the exact same barrel break in procedure then record the results at 1000 yard. I am keeping this short, just assume from beginning to end as many variables are either eliminated or greatly minimized and actual shooting has humans 100% eliminated.

The other 10 rifles, no break in procedures, but everything else is as identical as possible. shoot at 1000 yards, record results.

NOW you have data to make your case one way or the other.

has anyone ever done anything like this? I have never, ever heard of such a test. have you?

until a test like that or something close is done, barrel break in is just a hypothesis backed by superstitious learning based on a series of "sample of one."

You might argue those samples of one provide a lot of convincing data, but i would argue they really don't. To many variables are left uncontrolled. AND most importantly... no method to account for the path not taken is factored in. IF you don't have anything to generate data points for the path you didn't take (break in if you don't, don't if you do a break in) how can you factually or statistically claim one choice or the other is actually working or better or does what you think it does.

There is compelling data that does suggest that the rifle's accuracy improves as the reamers nicks and burs smooth out. BUT NO ONE has compelling data that a formal break in procedure (not to mention which one) is actually THE way to achieve the improved results vs just letting it happen naturally. Why...because everyone points to a sample of one to back up their claim. Even if over the course of your life you own a 100 rifles and do a break in procedure on everyone, you only have 100 samples of 1. too many variables to make a factual claim. with that approach. And again, no data to compare against for having NOT broken in your barrel.

a real test would be time consuming and expensive. till then... you pay your money, takes your chances. you make a choice based on how it makes you feel, nothing more.