02-21-2024, 08:47 PM
(This post was last modified: 02-21-2024, 08:49 PM by Diesel Pro.)
Alliant shows 223 data as follows 25.6gr 55SBK 24" barrel 3350FPS That's pretty compressed
Back off 50fps per inch (8x50=400) for my 16" barrel to 2950 expected
My actual observed with this load is 2768 with mediocre sd of 28.3
25.6gr of 8208xbr yields 2990 with sd of 3.9 and that is with a 5gr heavier bullet.
Not sure if anyone has ever drawn a direct comparison between comp and xbr but 230fps seems pretty significant and would be greater with same weight projectile. They aren't just too far apart in the burn rates. QL underestimates 8208 and overestimates my particular bottle of comp.
Back off 50fps per inch (8x50=400) for my 16" barrel to 2950 expected
My actual observed with this load is 2768 with mediocre sd of 28.3
25.6gr of 8208xbr yields 2990 with sd of 3.9 and that is with a 5gr heavier bullet.
Not sure if anyone has ever drawn a direct comparison between comp and xbr but 230fps seems pretty significant and would be greater with same weight projectile. They aren't just too far apart in the burn rates. QL underestimates 8208 and overestimates my particular bottle of comp.