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**Unclenick** · December 1, 2009, 02:37 PM

Mike,

The fired case numbers could be big if the neck on the brass is thinner than normal? Measure the OD of a neck with a bullet seated in it. A lot of commercial chambers run 2-4 thousandths bigger.

You might try semi-neck sizing. Use your regular FL sizing die, but only run the case in far enough that the sizing die is touches down on the sides. You should wind up with a neck resized most of the way, but not all the way to the shoulder. The short unsized portion helps center the bullet in the bore.

Also, you didn't mention if you'd measured loaded cartridge runout? That can make quite a difference to the accuracy of shorter bullets.

December 1, 2009, 02:37 PM	#5
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,060	Mike, The fired case numbers could be big if the neck on the brass is thinner than normal? Measure the OD of a neck with a bullet seated in it. A lot of commercial chambers run 2-4 thousandths bigger. You might try semi-neck sizing. Use your regular FL sizing die, but only run the case in far enough that the sizing die is touches down on the sides. You should wind up with a neck resized most of the way, but not all the way to the shoulder. The short unsized portion helps center the bullet in the bore. Also, you didn't mention if you'd measured loaded cartridge runout? That can make quite a difference to the accuracy of shorter bullets. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle