Help with 300 RUM velocity standard deviation
I am new to reloading and have just finished my first batch of test loads. I am shooting the following:
300 RUM Sendero
180 Grain Accubond
Federal Gold Medal 215M primers
I tested 5 different loads, the same COAL but i varied the powder charge by 1 grain with each load. I started with 95 grains of Retumbo and then 96, 97, 98, 99 grains. The load at 99 grains was by far the most accurate. Center to Center the 99 grain group was .244". The 5 shot group had the following velocities, in the order that they were shot, 3401, 3375, 3401, 3367, 3367. This is a total deviation of 34 fps.
Can anyone comment If this is a good deviation or if it is too large? If it is too large spread, what can i do to make the spread less.
Just so you know, at this charge the primer showed some very slight signs of high pressure, the primer had just barely begun to flatten. Also, the groups I shot were at 100 yards.
Thanks for your help.