Help Interpret This Data 280AI and H4831SC 22”

[Troutslayer2]

Here is the data from my new 22" Proof Sendero Barrel 1:8.4" twist. H4831SC and Nosler ABLR 168. This is the first 50 rounds fired. New Nosler 280AI brass.

Charge Average MV 5 shot group
56gr.- 2563
56.5 - 2598
57- 2610
57.5- 2663
58- 2689 Book Max - great group
58.2- 2669
58.4- 2689 SD 1.95, ES 4 not that great of a group.
58.6- 2725
58.8- 2710
59- 2774 great group, no pressure signs.


I am hoping to achieve 2800-2900FPS MV with 168 grain bullets. I am chasing that velocity so that I can feel comfortable with the energy it's still packing at 750YDS.

Like every time I do this I now have more questions than answers. How much will the barrel speed up? Am I going to be able to get to 2900FPS with this powder? I have no experience with compressed loads and I'm not sure how much more is going to fit in the case before I get there. Most of these loads have acceptable SD and ES and some of them are really, really low. I have a jug of this powder. Do I just keep on going .2 grains at a time? Any and all insight is welcome.

When does a barrel speed up and settle in? Am I wasting my time and components doing it like this?

 

[santee116]

I have a .280AI with a 22" Brux 1-9", so its comparable. I don't start working up loads or running a chrono until around 200 rounds (post any perceivable speed up), so I can't speak to this barrel speeding up or not. But below is my data from a 168 VLD with H4831sc and RL-26.

168 Berger vld, Nosler brass, CCI-BR2's

H4831sc
56.0 gr = 2606 fps
58.0 gr = 2677 fps (no pressure signs and great accuracy)

RL-26
58.5 gr = 2802 fps
60.5 gr = 2876 fps (no pressure signs and great accuracy)

Your velocities seem in-line with mine and H4831sc, but if you can find the unicorn known as RL-26, it should solve your velocity concerns.

Note: the barrel has around 750 rounds down the tube, so its well broken in.