I bought 300 175gr BTHP blems from Grafs awhile back. I assume they are Sierra Matchkings because the sectional density and ballistic coefficient match to a "T".
When setting up some loads to test out (varying charge weights), I adjusted the seater die so that the ogive was .010" off the lands. Set up my first loaded cartridge, and thought I was good to go. However, the second cartridge measured about .007"-.008" shorter than the first one I set up. This concerned me a little bit so I continued to measure every singe cartridge after that. to my dismay, they all seemed to vary in length. At first I thought the RCBS seater die was not doing a reliable job so I set up the Lee seater die and tried a few more. Same results.
Measurement to the lands with this particular bullet is 2.209". I set up the first cartridge to measure 2.200" to the ogive. The cartridges varied (regardless of seating die) average from 2.203" to 2.192" without me touching the seating adjustment.
This leads me to believe there is inconsistency from bullet to bullet as far as the shape goes. I know these were sold as blems, but should there be that much difference in measurement?
This also begs the question of whether or not the difference in length will affect my ability to do a proper OCW or even accuracy check.
Will a seating difference varying by around .010" from cartridge to cartridge affect my ability to shoot small groups, or is this too small of a variance to worry about?
I did separate them by OAL (to ogive) as I was loading and measuring so that I have at least three cartridges of the same powder charge and same length to the bearing surface.
Is this unacceptable, or am I being too picky?
Furthermore, I thought blems were just cosmetic in nature.
Thanks for any input.
When setting up some loads to test out (varying charge weights), I adjusted the seater die so that the ogive was .010" off the lands. Set up my first loaded cartridge, and thought I was good to go. However, the second cartridge measured about .007"-.008" shorter than the first one I set up. This concerned me a little bit so I continued to measure every singe cartridge after that. to my dismay, they all seemed to vary in length. At first I thought the RCBS seater die was not doing a reliable job so I set up the Lee seater die and tried a few more. Same results.
Measurement to the lands with this particular bullet is 2.209". I set up the first cartridge to measure 2.200" to the ogive. The cartridges varied (regardless of seating die) average from 2.203" to 2.192" without me touching the seating adjustment.
This leads me to believe there is inconsistency from bullet to bullet as far as the shape goes. I know these were sold as blems, but should there be that much difference in measurement?
This also begs the question of whether or not the difference in length will affect my ability to do a proper OCW or even accuracy check.
Will a seating difference varying by around .010" from cartridge to cartridge affect my ability to shoot small groups, or is this too small of a variance to worry about?
I did separate them by OAL (to ogive) as I was loading and measuring so that I have at least three cartridges of the same powder charge and same length to the bearing surface.
Is this unacceptable, or am I being too picky?
Furthermore, I thought blems were just cosmetic in nature.
Thanks for any input.