Sorry I took so long to reply to you. The basic load for the Barnes 600 Original Bullet was 65.0 grains of VARGET powder. I have my .458 in a Ruger # 1, Tropical Rifle. I loaded this round out to 3.603". It chambers nicely. The .600 Barnes Original Bullet is 1.650 " long. You won't be able to come near the cannelure on this bullet, so don't try to. I fired this round off a shooting bench, but do not recommend it for plinking. I wanted a stopping round without breaking the bank, this one will do the job. Thanks for the e-mail. Bill