The Firing Line Forums - View Single Post - science or myth behind barrel break in ???

JD0x0 · February 4, 2014, 02:01 PM

By not cleaning for 20-30 shots you are allowing copper jacketing to fill in the 'imperfections' which you are trying to smooth out by breaking in the rifle. This is why you're instructed to clean every 1-2 shots, at least for the first few shots. By cleaning every shot, you're getting that jacket fouling out of the 'imperfections' and slowly smoothing them out with each shot, as long as you don't let them get filled in with fouling. If you do let them get filled with fouling, no real harm or foul, you just wont be smoothing out those areas of the barrel. There is no magic in barrel 'break in.'

The whole idea is to smooth out the imperfections in the bore, by firing rounds, and cleaning. By having a more 'perfect' bore, it will be easier to clean, and also it should accumulate less fouling for a given number of shots. This doesn't make the rifle more accurate, but it could maintain acceptable accuracy for more shots.
Some rifles will benefit from a 'break in' more than others. Some barrels wont improve with a break-in at all. As I've stated there usually wont be any change in accuracy, a 'break in' wont make or break your gun. What it should do, if done properly, is reduce the frequency of cleanings once the barrel is broken in, it'll make the fouling easier to remove, and due to the slower build up of fouling, because there are less or no imperfections, which are stripping jacket material off the bullet, onto the bore, you can maintain best possible accuracy for a longer number of shots. I guess some could argue that by having some of the jacket material stripped off, in the bore, that it could slightly throw the balance of the bullet off, and reduce accuracy. Personally, I don't think it would be noticeable.

February 4, 2014, 02:01 PM	#4
JD0x0 Senior Member Join Date: January 30, 2013 Posts: 1,037	By not cleaning for 20-30 shots you are allowing copper jacketing to fill in the 'imperfections' which you are trying to smooth out by breaking in the rifle. This is why you're instructed to clean every 1-2 shots, at least for the first few shots. By cleaning every shot, you're getting that jacket fouling out of the 'imperfections' and slowly smoothing them out with each shot, as long as you don't let them get filled in with fouling. If you do let them get filled with fouling, no real harm or foul, you just wont be smoothing out those areas of the barrel. There is no magic in barrel 'break in.' The whole idea is to smooth out the imperfections in the bore, by firing rounds, and cleaning. By having a more 'perfect' bore, it will be easier to clean, and also it should accumulate less fouling for a given number of shots. This doesn't make the rifle more accurate, but it could maintain acceptable accuracy for more shots. Some rifles will benefit from a 'break in' more than others. Some barrels wont improve with a break-in at all. As I've stated there usually wont be any change in accuracy, a 'break in' wont make or break your gun. What it should do, if done properly, is reduce the frequency of cleanings once the barrel is broken in, it'll make the fouling easier to remove, and due to the slower build up of fouling, because there are less or no imperfections, which are stripping jacket material off the bullet, onto the bore, you can maintain best possible accuracy for a longer number of shots. I guess some could argue that by having some of the jacket material stripped off, in the bore, that it could slightly throw the balance of the bullet off, and reduce accuracy. Personally, I don't think it would be noticeable. Last edited by JD0x0; February 4, 2014 at 02:09 PM.