I finally got my hands on a box of Sierra’s new Game Changer hunting bullets for use in .223 caliber. Lacking data, I called Sierra. They told me to use 65 grain Game King data. I have used the 65 grain GK in the past and found it to be fairly accurate with H-4895. 24.7 grains produced .8” 100 yd groups at 3150 fps with a SD of 13. Still, that is nowhere near as accurate in my gun as the 69 grain SMK or TMK.
Using Hornady’s COAL tool, I consistently got a measurement of 2.240 in my 26” Sheilen Wylde chambered barrel (Savage 12 action). This is a much shorter COAL than with 69 grain SMK bullets because the ogive on the Game Changer is located much closer to the tip of the bullet. I attached a pic for comparison. Before anyone asks, no - I don’t have a base to ogive measuring tool.
Based on past tests with other bullets, I decided on a COAL of 2.238 for the initial charge weight test.
I don’t have any H-4895 so I am testing 23.4-24.2 grains of VV N135 in .2 grain increments. 23.8 is my best 69 SMK load at 2.325 oal. I loaded 7 rounds of each charge in Starline brass trimmed to 1.743. (I hope that shortish trim length doesn’t affect me too much.) I’ll see if any of them group at 100 yards today. If not, I’ll start over with Lapua brass trimmed to 1.75 and maybe try the Varget I have stashed away for .308.
When/if I find a load that groups I’ll chronograph it for SD, test @ 200 yards and report back. Out of my rifle, these charges will all produce around 3k+ fps so velocity is more for information about drop/windage than a desired outcome. Acceptable accuracy is the goal.
Using Hornady’s COAL tool, I consistently got a measurement of 2.240 in my 26” Sheilen Wylde chambered barrel (Savage 12 action). This is a much shorter COAL than with 69 grain SMK bullets because the ogive on the Game Changer is located much closer to the tip of the bullet. I attached a pic for comparison. Before anyone asks, no - I don’t have a base to ogive measuring tool.
Based on past tests with other bullets, I decided on a COAL of 2.238 for the initial charge weight test.
I don’t have any H-4895 so I am testing 23.4-24.2 grains of VV N135 in .2 grain increments. 23.8 is my best 69 SMK load at 2.325 oal. I loaded 7 rounds of each charge in Starline brass trimmed to 1.743. (I hope that shortish trim length doesn’t affect me too much.) I’ll see if any of them group at 100 yards today. If not, I’ll start over with Lapua brass trimmed to 1.75 and maybe try the Varget I have stashed away for .308.
When/if I find a load that groups I’ll chronograph it for SD, test @ 200 yards and report back. Out of my rifle, these charges will all produce around 3k+ fps so velocity is more for information about drop/windage than a desired outcome. Acceptable accuracy is the goal.