09-29-2021, 09:58 PM
I used CFE 223 extensively in 6.5G for several years. I loaded 30.8 gr with 123 gr Scenars and that was right near the limit for my somewhat tight chamber (22" JP). I used 2560 in my ballistics app. I was in the mountains of CO and had about a 7 month shooting season and would shoot from temps of about 50 to 90. Ammo storage temp was relatively stable at 65-75 degrees and I was generally able to keep it out of the sun at the range. It ran around 2640 or a little slower on the cool days and up around 2580/2590 on the warm ones. If I was on one end of the temp spectrum it would take a few shots to adjust the dope at 1k (which is a lot closer at 7k ASL than it is at sea level).
When I moved to Arizona, I knew that load wouldn't work and would need adjustment, especially since I was about to start competing. I ended up deciding upon 30.4 gr which ran 2600 at 95°. I shot just one of the old 30.8 that day and it ran 2660 with a seriously flattened primer. I loaded 100 up for my first match expecting an average temp of 95, and it ended up being a day that was actually cloudy with a temp of around 80. I was all over the place. Best estimate is that I was running 40 fps slow, but the worst part was that my zero shifted and accuracy blew out to about 2 MOA.
The moral is that it gets extremely sensitive and the curve steepens once you get above 90 degrees. It's hearsay, but I've heard similar reports of a steepening curve down around freezing. I personally have sworn off all ball powders, but recognize that I do live in an extreme climate with a 12 month shooting season.
Is the course your taking a practical shooting type course? I don't want to assume so, but have some insight that would make you comfortable with H4895 velocities if it is.
When I moved to Arizona, I knew that load wouldn't work and would need adjustment, especially since I was about to start competing. I ended up deciding upon 30.4 gr which ran 2600 at 95°. I shot just one of the old 30.8 that day and it ran 2660 with a seriously flattened primer. I loaded 100 up for my first match expecting an average temp of 95, and it ended up being a day that was actually cloudy with a temp of around 80. I was all over the place. Best estimate is that I was running 40 fps slow, but the worst part was that my zero shifted and accuracy blew out to about 2 MOA.
The moral is that it gets extremely sensitive and the curve steepens once you get above 90 degrees. It's hearsay, but I've heard similar reports of a steepening curve down around freezing. I personally have sworn off all ball powders, but recognize that I do live in an extreme climate with a 12 month shooting season.
Is the course your taking a practical shooting type course? I don't want to assume so, but have some insight that would make you comfortable with H4895 velocities if it is.
#FJB