Originally Posted by remingtonman_25_06
My .222 rem gives me at most 15fps, and is usually within 10fps with its couple better loads. I am about .010"-.015" off the lands using CCI400 primers. Use IMR-4198 w/40g bullets and IMR-4895 w/55g bullets. Neck sized in a RCBS die. I dont know, I always thought smaller cases were easier to get lower deviations??? Never had a problem with my triple deuce getting low spreads.
Those are very good SDs !
It is the smaller bullets that are harder to get low SDs because of the weights of the bullets
compared to the velocity.
The smaller the bullet the more it is effected buy any difference in primers, neck tension, seating
depth, temperature and even the accuracy of the bullet weight . For example= If 500gr bullets
vary by 1/10 of a grain the difference will be 2/100 of 1 percent. but if 50gr bullets vary
by 1/10 of a grain then the percentage is 2/10 of 1 %.
It is not hard to get big bore bullets in the 400 to 600gr range down to single digits because slight differences have less effect on them.
The smaller cases do have an advantage in combustion Pressures because of faster powders
and smaller volume's .
J E CUSTOM