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Bart B. · January 21, 2021, 05:53 PM

It may have been Col. Hatcher who knew that bullets need to be at least a few ten-thousandths inch larger than the barrel's groove diameter for best accuracy..

Why else would arsenal 173 grain FMJBT .3086" match bullets mic larger than M1 and M14 barrel groove diameters?

When the British commonwealth started shooting 7.62 NATO M80 ball ammo's. 3070" bullets in their fullbore rifles, best accuracy was with 1:13 or 1:14 twist 30 inch barrels having. 3065" groove diameters

And all the best match winning record setting barrel's groove diameter smaller than the best match bullet's diameter.

January 21, 2021, 05:53 PM	#14
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	It may have been Col. Hatcher who knew that bullets need to be at least a few ten-thousandths inch larger than the barrel's groove diameter for best accuracy.. Why else would arsenal 173 grain FMJBT .3086" match bullets mic larger than M1 and M14 barrel groove diameters? When the British commonwealth started shooting 7.62 NATO M80 ball ammo's. 3070" bullets in their fullbore rifles, best accuracy was with 1:13 or 1:14 twist 30 inch barrels having. 3065" groove diameters And all the best match winning record setting barrel's groove diameter smaller than the best match bullet's diameter. Last edited by Bart B.; January 21, 2021 at 06:03 PM.