The Firing Line Forums - View Single Post - New Pistol Break In Period Before Load Development?

Bart B. · January 11, 2013, 07:43 AM

I don't think any barrel needs to be broken in for accuracy.

I asked Sierra Bullets' ballistics manager decades ago about that for their match-grade rifle and pistol barrels used to test their bullets for accuracy. He said there was no significant difference in accuracy across the first few dozen, few hundred or few thousand of rounds fired. They all did loose a tiny bit of accuracy after about 2/3rds of the expected barrel life in rounds fired was met, but it was only about 10% to 15%; barely enough to be noticable.

A friend was a NRA National Pistol Champion holding several records and his comments were the same on breaking in barrels. He said to just shoot the darned things. Nobody's gonna be able to tell when a pistol barrel has an accuracy change of a dozen percentage points either way; better or worse. Nobody holds and shoots pistols good enough to tell.

One needs to shoot test groups having at least 50 shots for them to be statistically significant anyway. If one does do that, twice, and both groups are not the same size, then they've not shot enough shots per group to get valid data.

January 11, 2013, 07:43 AM	#2
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	I don't think any barrel needs to be broken in for accuracy. I asked Sierra Bullets' ballistics manager decades ago about that for their match-grade rifle and pistol barrels used to test their bullets for accuracy. He said there was no significant difference in accuracy across the first few dozen, few hundred or few thousand of rounds fired. They all did loose a tiny bit of accuracy after about 2/3rds of the expected barrel life in rounds fired was met, but it was only about 10% to 15%; barely enough to be noticable. A friend was a NRA National Pistol Champion holding several records and his comments were the same on breaking in barrels. He said to just shoot the darned things. Nobody's gonna be able to tell when a pistol barrel has an accuracy change of a dozen percentage points either way; better or worse. Nobody holds and shoots pistols good enough to tell. One needs to shoot test groups having at least 50 shots for them to be statistically significant anyway. If one does do that, twice, and both groups are not the same size, then they've not shot enough shots per group to get valid data. Last edited by Bart B.; January 11, 2013 at 07:50 AM.