Most shooters have heard that you need to break in your rifle barrel. However, most shooters have no idea “why” you need to break in your rifle barrel. If you buy a custom rifle from any reputable maker it will come with instructions on how to break in the barrel. However, I have never seen any large rifle manufacturer give instructions or even recommend how to break in a rifle barrel. Most shooters are so excited to go out and shoot their new rifle; they won’t even clean the barrel before they take it out to shoot it for the first time. All rifles should be cleaned before shooting. Rifles are shipped with packing oil or grease, which needs to be removed before you start shooting. You won’t damage your rifle if you don’t but you will wonder why you are not hitting any thing the first few shots.
Why would you have to clean or break in a new rifle barrel? The first few shots fired from your rifle are some of the most important shots that you will ever fire. When a rifle barrel is made, the riflings are cut, as well as, the chamber. All the cuttings in a rifle barrel are done with buttons or reamers as well as, chamber reamers. All of these tools will leave small burrs or cut marks inside the barrel. The last thing you want is for these cut marks to get worse and turn into small holes. If you end up with small holes in the barrel, these holes will start to strip brass or copper from the bullets. The holes will also fill up with carbon from the burned powder. The carbon will start rust or corrosion in the barrel. The corrosion will make the holes bigger which will strip more brass from the bullets and so on. What you end up with is a nasty cycle which leads to an inaccurate rifle or one that will have a shortened life. I just worked on a Kimber rifle which would not shoot any more. The barrel had never been cleaned let alone having had proper break in. The rifle was ruined and needs a new barrel.
Well, I have broken in hundreds of rifle barrels in my lifetime, but I have never given one a true test just to see how much breaking in a barrel properly would help with accuracy. I grabbed a new Remington 700 in 30-06 caliber off the shelf. I did a quick trigger adjustment, setting the pull at 3 pounds, and then I loaded my favorite 30-06 load of 165gr. Hornady boat-tail bullets and 57 grains of IMR 4350. I packed my cleaning equipment, 2 boxes of factory ammo and headed to the range. My normal break in procedure is to shoot the rifle, clean it and shoot it again and clean it again. I do this for the first 10 shots. I then will clean the barrel after every three shots for the next 20 shots. This time I wanted to see how much difference breaking in a barrel on a factory rifle could really make.
The first thing I did was to shoot a three shot group with my handload for both accuracy and velocity. The group surprised me, a .910 group from a factory rifle with nothing done to it but a trigger adjustment. The velocity was where I figured it should be at 2784 feet per second with an extreme spread of 55 FPS. I then cleaned the rifle. I used the same cleaning routine from then on. First, I would run a solvent covered brush through the barrel five times, then I would run five Sweets soaked patches through the barrel and follow up with three patches soaked with Gum-Out carburetor cleaner to remove the Sweets. For the last step, run one dry patch through the gun to dry everything out. I would then shoot one round of factory ammo. I did the same shoot and clean, shoot and clean process until I had ten rounds fired through the rifle. Then, I went to a three shot routine of shooting three shots and clean and shoot three shots and clean. I used the same cleaning program for the three shots as I did for the one shot. Some shooters think Sweets is too harsh on the barrel, but I have had great luck with it. I just don’t let the Sweets sit in the barrel for a long period of time. Once I start a cleaning job I try to finish it. I use Gum-Out because it is inexpensive and works as well as any gun solvent I have found.
I noticed by the time 16 rounds had been fired through the rifle that cleaning became easier. I had a lot less copper fowling and blue color on the patches than I did when I started. Maybe it was just me, but it seemed easier to push the patch through the barrel which made me think that the barrel was starting to smooth out. By the time I had fired and cleaned 31 times, the rifle cleaned very easily with very little blue on the patch. My last cleaning was very thorough. I spent more time cleaning the barrel so I could see what kind of group the rifle was capable of with a properly broken in barrel. I set up the chronograph and fired three shots. The results amazed me! The group was under ½ inch at a .260 and the velocity had picked up more than 70 feet per second. The extreme spread was less than 40 feet per second with an average velocity of 2856 FPS.
The entire process took just over two hours and by the time I paid range fees, for two boxes of factory ammo, the components to load a box of custom ammo I spent just over $100.00. Now, that is about the most inexpensive way I know of to make a rifle accurate. The rifle was very accurate to start with, but the cleaning and shooting just made everything better. Picking up seventy feet per second is great, but the rifle might have done this on its own after some shooting time anyway. But maybe not! The rifle could have gone the other way and ended up shooting worse than when I started.