Ysterhout Dot Net

IMR 4955 was used for the final test, IMR 4451 for the first.

Powder data for 4955 was derived from the 1997 Hodgdon guide, stating H4831 with 235 grain bullets, 86 grains maximum for 2665 fps.

H4831 is meant to be replaced by IMR 4955, but I know from previous experience with the powder that 4955 is hotter to the extent that when used equivalently, starting loads using 4955 approach the max velocity of max loads of H4831.

I chose to start at 70 grains, using half a grain of dacron.

Included for reference is the data from the first test using IMR 4451.

Bullet Powder Charge Grains Velocity fps
 
245 grain lead, paper patch IMR 4955 70 2440 average
245 grain lead, paper patch IMR 4955 72 2530 average
245 grain lead, paper patch IMR 4955 74 2565
 
245 grain lead, paper patch IMR 4451 64 2152
245 grain lead, paper patch IMR 4451 66 2264
245 grain lead, paper patch IMR 4451 68 2312
245 grain lead, paper patch IMR 4451 70 2366

Last Updated 7 Oct 2023 at 10:17:37