311 vs 312 for the 303

[rmckeon]

Hi all,

I'm trying to figure out why some shops tell you to use the 312 cal projectile, and others push the 311's... I have a minty barrel, so I'm wondering if I should stay away from the 312's.

Any thoughts on this?

Thanks!!

Information

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[JBS]

Slug your bore. If it is .311 you can shoot a .311 or .312 but reduce powder and work back up if you go with .312 You will find that if you have a .311 and use .311 boattails you may get blow by and loose some accuracy. I have a unissued 1955 Faza and it loves the .312s and 4064 If you have a 5 land 5 grove barrel you will have to use a V caliper to measure your slug from the bore.

[AKA Hugh Uno]

as long as you are 10% below maximum loads, it makes no difference. I would INTENTIONALLY shoot the larger bullets first as they would probably tend to shoot better.

I also agree that 4895 is the best "first choice" in .303.

[ireload2]

There is a good chance your barrel may be as large as .314 to .317.
If so .312 is still under size.