Clean bore vs. fouled bore for 1st shot accuracy

[jrock]

Gentlemen, I have read so many articles about getting the best accuracy from a shiny clean bore and then along comes someone telling how a fouling shot gives the best. I would welcome your thoughts. not just your thoughts but also your reasoning.

Well I did my own bore mapping with my 7mm RM factory rem 700. When it was new, the first two shots didn't group with the rest. Now that it has about 400 rounds down range, the first one doesn't but the second does. For hunting, I'll foul the bore with 1 shot before going out so I have confidence it will hit where I'm aiming. I've heard custom guns don't have this problem.

Check out youtube and G7 for bore mapping tips

 

[Bart B]

If one has ever watched match winners and record setters clean their bores every 30 to 40 shots with a solid steel rod and no crown protector and have no accuracy loss for the 3000 to 4000 round life of the barrel, they may question the Crown Cradle's usefulness.

Same thing for 7.62 NATO chambered Garands and M14NMs rebuilt to shoot all rounds of commercial match ammo inside 4 inches at 600 yards. After as many rounds, the bullets no longer leave any copper wash for the last 1/2 to 3/4 inch of the bore. Barrel steel has been rubbed away belling the bore and groove diameters .002" more at the crown than when new. Accuracy's the same as when new.

The barrel's throat erodes away from hot, high pressure gas from firing much more than the last inch of the barrel.

 

[gunner69]

Some may and if so wouldn't buy one. We are getting lots of interest from top names in competitive shooting however so some see it differently.

 

[Bart B]

Then there's the issue of a few shots credibility of representing the system's accuracy.

The first 3-shot group's size tell you that the size of 20 more will range from only 40% as big to 245% as big. If it's one inch, then subsequent ones will be from .4" to 2.45" in extreme spreads.

With a 1" 5-shot group, subsequent ones will be from .67" to 1.53"

If a 1" 20-shot group's fired, subsequent ones will be from 1.12" to .89" in size.