.243 100 Grain Partition Seating Depth Suggestions

[TBASTIAN]

I was hoping to get some advice on seating depths for the 100 grain Partition in a .243 Browning A-Bolt. I'm hovering right at an inch for three shot groups with 41.5 grains of IMR4350.

The bullet touches the lands at 2.715" OAL.

I've tried 2.570" for 0.95" and 1.10" groups and 2.680" for a 1.02" group.

Does the Partition traditionally like being seated closer or farther from the lands? Trying to figure out which way to go prior to my next range trip. Thanks.

 

[rick smith]

The loaded round must fit into the mag box, feed/function and not be jammed into the lands. I normally start 10-15 thou off the lands and work back in 0.005" using three shot groups. There is no magic being close to the lands, just a starting point. With many of the short action rounds the mag box determines where I start. Every rifle is different as to likes/dislikes, just have to try. If this rifle is for deer hunting, you could stop with a one inch group and kill all the deer you want. But I would test it at longer distances. You should try accubonds in it also. Rick.

 

[joelkdouglas]

Some light reading on Berger's recommendation. Works for ABs and PTs also.

http://www.eabco.com/Berger%20Bullet%20 ... ethod.html

The document is also in the Berger manual.

FWIW, my rifle prefers both ABs and PTs about 0.090 off the lands. Not to say yours will.