I was able to get out again today and get a little more time with 50.2gr load. This time I was using a Magnetospeed chrono. This load was averaging closer to 2930 fps, a little slower than I had been hoping for. I think my previous chrono may have been. It was 28C out today and I was seeing little to no signs of pressure at all. ES was around 40 fps, SD at 17 and shooting approximately 1 MOA over a total of 10 rounds. With a little more tweaking and some more attention to neck tension I could probably bring those values down a bit. I may look around 50.8 gr again to see if I can get closer to 3000 fps with good accuracy.
I was also able to break the 3000fps mark with Varget, but settled on a good accuracy node at 44.6 gr and 2925 fps.
I think I'll likely settle on the Varget load as ED and SD were both much lower compared to Staball
I was also able to break the 3000fps mark with Varget, but settled on a good accuracy node at 44.6 gr and 2925 fps.
I think I'll likely settle on the Varget load as ED and SD were both much lower compared to Staball
I got out and did some shooting with my 22" barreled 7-08 AI today. I had loaded 2 shots at each charge weight using Staball 6.5 and 140 gr Nosler BT seated to mag length. I was mostly looking for velocity nodes and attainable velocities while watching for pressure signs. Results as follows:
Load # - Charge - Velocity 1, velocity 2
#1 - 47.5 gr - 2795, 2841
#2 - 48.0 gr - 2788, 2834
#3 - 48.5 gr - 2893, 2860
#4 - 49.0 gr - 2910, 2900
#5 - 49.3 gr - 2952, 2933
#6 - 49.6 gr - 2992, 2936
#7 - 49.9 gr - 2979, 3001
#8 - 50.2 gr - 2998, 3001
#9 - 50.5 gr - 3051, 3011
#10 - 50.8 gr - 3061, 3070
#11 - 51.1 gr - 3070, 3077
#12 - 51.4 gr - 3113, 3106
Loads started becoming compressed at around 50 gr charge, however, I was not using a drop tube and likely would have been better if I did. There was very little signs of pressure on the brass for all charge weights with the exception of very slight primer flattening starting around load #6-7 and one very very slight extractor mark on the second shot of load #12 (an astute inspector would notice a very light extractor mark on the second shot of load #9 which was from some previous load testing that got a wee bit hot). I am going to do a little more exploring around 49.9 - 50.4 gr and 50.8 - 51.1 gr.
Brass in the photo are loads:
#1 #6 #11
#2 #7 #12
#3 #8
#4 #9
#5 #10
Based on these results I would say it is definitely plausible that a 7-08 could reach 3100 fps using Staball 6.5 and a regular 24" or longer barrel. If this powder proves to be as stable as claimed, hopefully it might be a winnner.
