I got the CH4D neck sizing insert die and squeeze the .303 British necks down to hold a .304 180 gr. Hawk Bullet. I used beginning load data for a 180 Gr. Sierra bullet and loaded 3 rounds.

Went out to the range this afternoon and fired the three rounds.

No problem. No pierced primer, no head separation. Brass fired, extracted and eject easily.

When I got home I tried to insert a .311 bullet into the fired case necks and it would not go.

Now to build some loads for the this gun.