Load Development--Seating Depth and then Powder Charge?

[HTSmith]

So I have a new (to me) 6BR along with a new jug of Varget, new Lapua cases, and a new lot of Berger 105's. I did a pressure test and I can get up to 30.4 Gr of Varget (rifle has a long throat) with reasonable pressure. So my question is do I find my seating depth with a mild charge and then work on powder or do I find the best powder charge and then adjust seating depth? Are these variables independent? I've found good loads before, but I need to get there this time without using so many scarce components. Thanks for your input.

 

[rckendall]

Lately, I have been following the recommended practice by the Berger Tech guys who say to find the jump (seating depth) first using a low pressure charge, then work on the load.

For the Hybrids they suggest starting at .015 off the lands and increase out to .045 in .005 increments, I believe. But, call them yourself and listen to what they say. They are always willing to help.

Richard

Edit to add: I shoot 3 shot groups to get the seating depth and then 5 shot groups to find the charge weight. You may then want to fine tune the seating depth using smaller incriments.

 

[mikeinct]

I try to load 3 to 5 cartridges in each group under the max powder charge, I normally divide by 2/10's or 3/10's grains, 3 or 5 cartridges each......Then I look for the group with the least amount of vertical at 100 or 200 yds..My starting tests are 12 to 15 thou off the jam in the lands..After I decide which powder charge is it..The roundest group w minimal vertical ..Then I mess with the seating depth..Mike in Ct

 

[Richard Coody]

30 gr varget 105 hybrid .005 off a hard jam. br4

 

[HTSmith]

30 gr varget 105 hybrid .005 off a hard jam. br4

That sure worked for my other two. It was easy as pie. With the long throat, this one is a different beast. Thanks

 

[mikecr]

do I find my seating depth with a mild charge and then work on powder

Yep
Follow Berger's recommended testing -regardless of bullet/brand.