Barrel Break-in?

Q: I have a new rifle in .300 WSM and have been advised by the club expert to break it in by firing a series of 10 single shots, each followed by a thorough cleaning; then 10 three-shot groups, each followed by thorough cleaning; then a series of five five shot groups, each followed by thorough cleaning.

He claims that this smooths out all the imperfections left in the bore during manufacturing, and that it polishes the bore by getting rid of any copper fouling left between shots.

This seems like a lot of work and I read where you claimed that you have never broken in a barrel in your life and don’t consider it to be necessary.

Who is right and who is wrong? Should I follow the expert’s advice and break-in my new barrel?

Martin Waugh

A: I’d never argue with an expert, but I do things my own way and have never noticed any problems.

Not all rifle barrels benefit from the break-in process and unless the repeated cleanings between shots is very carefully carried out, you could end up reducing the barrel’s accuracy more than if you’d never tried to break it in.

Gunsmiths have told me that they replace more barrels damaged by improper cleaning than are actually worn out by a lot of shooting.

To add another anti-break-in factor, it is a fact that the thin coating of copper-fouling visibly apparent in the bore can actually enhance accuracy rather than reduce it.

I am of the opinion that firing 65 shots through your new barrel is unwarranted. Modern barrels are well finished internally and many are hand-lapped and polished.

Maddco, who makes fine custom barrels, recommends treating a new barrel as follows: run a patch through the bore to clean out any dust or oil. Fire two or three shots, then clean. Fire 5-7 shots and clean again. Then assume a regular cleaning procedure. This is for benchrest rifles, not sporters.

However, you please yourself as to whether you follow the break-in process your ‘expert’ recommends. One thing’s for sure: it ain’t gonna turn a bad barrel into a tack driver.




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Nick Harvey

The late Nick Harvey (1931-2024) was one of the world's most experienced and knowledgeable gun writers, a true legend of the business. He wrote about firearms and hunting for about 70 years, published many books and uncounted articles, and travelled the world to hunt and shoot. His reloading manuals are highly sought after, and his knowledge of the subject was unmatched. He was Sporting Shooter's Technical Editor for almost 50 years. His work lives on here as part of his legacy to us all.