Barrel running in procedure

[WelshShooter]

If a new barrel has burrs then it hasn't been made properly. Modern machining techniques should result in a barrel with no such problems, hence if there are such defects present the barrel should be returned as unfit for purpose. There's no excuse for poor workmanship nowadays (if there ever was...)

I cannot comment on this as I don't have a borescope to inspect if such markings exist. I would therefore rather be on the conservative side since I also don't know what tooling has been used to make and fit the barrel.

[Steve E]

Having discussed this very topic with some of the finest barrel makers and gunsmiths whilst here in Camp Perry and showing some of them this thread, they are all of the opinion that the monochrome mammal knows diddly squat about barrel manufacture, the chambering and the running in of barrels. Do what the barrel manufacturers advise and not what monochrome mammals theorise.

[Airbrush]

I'm picking up my new barrel for the AR tomorrow, it's a Border button.

According to Border they recommend this break in procedure.

1shot. Clean x 3.
2shot. Clean x 3.
3 shots. Clean x 3.
Total 18

Having done a lot of research copper equilibrium seems to be the most important part for me, ie when a barrel is 'run in' it doesn't take so much cleaning to get the copper back to a benign level.

I'm new to all this as the last barrel was my first CF & that had 1500 rounds through it when I got it.

[hitchphil]

http://www.hps-tr.com/products/gun-clea ... unning-in/

............ regardless of the accuracy of the tooling & its material used; how swarf is managed, cutting rates, lubricant & feeds are all rather important & will determine the presence of micron level radial marks in the chamber (not a great problem) or in the throat (more an effect) or in the leads / lands (they will slice copper off the bullets). micron level surface features in the barrel & especially in the base of the rifling grooves will also strip copper.

Copper is the enemy, surface topography determines coppering. just as metal hardens because grains get disrupted & smaller (dislocations in the copper crystallographic structure cant move over grain boundaries during deformation) , small thin deposits of highly deformed copper on surfaces can become hard & like abrasive (indeed the blocks of the pyramids of Egypt were cut with copper chisels) that abrasive effect changes how friction, heat transfer & how a bullet behaves in a barrel.

bullets not enter the leads radially with machining marks they move axially & jump across any surface abrasions & burrs entering the barrel. That also can cause copper to be deposited. They then have a radial twisting acceleration along the barrel length to the last length of barrel where pressure becomes a maximum before they emerge spin stabilise & gyro fly. That last length of barrel can be critical to accuracy.

There is no such thing as a flat & smooth surface, even a custom barrel wall will have undulations & changes to its surface that may only be measured as a fraction of a wavelength of the examining light but they will also affect how bullets mould to the wall & how friction affects the generation of heat & transfer of material from bullet to barrel wall or rifling groove on motion.

per the article I too have taken a P14 target barrel shooting 3-5 moa with visibly green rifling & returned it to ~3/4moa accuracy by cleaning the copper out (it took a week but it worked). & every target rifle shooter achieving 1/4 to 3/4 moa accuracy at long range does this cleaning & barrel running procedure for good very reason. If you shooting a lower tolerance & specified military style barrel you may indeed not see these effects ....................... until it wears out prematurely.



Just my view as a a dumb old Metallurgist & Materials Engineer that has worked on surface science of Le Mans race car bearings, missile mechanisms & spacecraft optics ;-)

[Mike95]

Get some H & N HS copper plated bullets....shoot light loads (to 2000fps) These bullets have a plastic coating and will not leave any copper deposits on the barrel...at least with light loads. This procedure used with a Howa 308.....Howa started grouping fine after 50 rounds...not a trace of copper fouling.

Mike95

[Rburro2]

Just shoot it and enjoy it then get it home and clean it. I would clean it before I took it out for the first time then just crack on as usual. Remember over cleaning can be as bad as under cleaning

[Charlotte the flyer]

Remember over cleaning can be as bad as under cleaning

Can you please explain further. Other than the AR15 locking lugs, which I can't get shiny for love nor money, everything else that I own get a mega clean after each session. If it doesn't look like the start of a bond film then I keep going until it is.

[Marmite5]

Just shoot it, that's all that's needed and then clean it when you get home.

[The Gun Pimp]

Just shoot it, that's all that's needed and then clean it when you get home.

You can do that - but it could take an awful long time to get all the copper out - like a few days..........

Most shooters won't bother do this thoroughly, end up with a coppered-up barrel and never get the best out of their rifle.

Your choice.

[Rburro2]

Remember over cleaning can be as bad as under cleaning

Can you please explain further. Other than the AR15 locking lugs, which I can't get shiny for love nor money, everything else that I own get a mega clean after each session. If it doesn't look like the start of a bond film then I keep going until it is.

Many a good 22lr destroyed with brushes and chemicals.

I clean my ar15 every 300 rounds and then i need 10 shots to foul the barrel before its shooting well, Chris b's gun is the same dont get me wrong if it gets wet i dry it off and give it a light oiling. The new modern powders are not corrosive so the rifle doesnt need to be imaculate after every use.

And over cleaning example: putting ar15 carrier into ultrasonic cleaner removing coating. Our guns arent gas operated so they usually just need a wipe off with an oilly rag.