Hey guys, new member here but not at all new to the sport. I thought I would share some interesting info that I learned in the last year. Apologies if this has been discussed before.
While working up a new load last year for my 300 RUM I noticed that my "fresh" loads (loaded within a day or two of shooting) had a considerably higher MV than loads that had sat for about two weeks or so. I am full length sizing all my brass the same way with a redding bushing die and the expander mandrel installed. All loads were the exact same specs but the fresh loads were around 3135 FPS with an ES of around 20 FPS and the 'seasoned' loads shoot around 3075 FPS with the same ES.
I know that a lot of benchrest shooters load and shoot immediately, even loading at their vehicle before the match. As a hunter I can't really do this so now I prefer to 'season' my loads for a couple weeks before shooting.
To back this up, a buddy of mine I shoot with noticed the exact same thing on his 6.5 CM while we were shooting together.
Simply put, I believe brass will 'stress relieve' over time which results in slightly less neck tension. This, I assume is causing this to happen.
While working up a new load last year for my 300 RUM I noticed that my "fresh" loads (loaded within a day or two of shooting) had a considerably higher MV than loads that had sat for about two weeks or so. I am full length sizing all my brass the same way with a redding bushing die and the expander mandrel installed. All loads were the exact same specs but the fresh loads were around 3135 FPS with an ES of around 20 FPS and the 'seasoned' loads shoot around 3075 FPS with the same ES.
I know that a lot of benchrest shooters load and shoot immediately, even loading at their vehicle before the match. As a hunter I can't really do this so now I prefer to 'season' my loads for a couple weeks before shooting.
To back this up, a buddy of mine I shoot with noticed the exact same thing on his 6.5 CM while we were shooting together.
Simply put, I believe brass will 'stress relieve' over time which results in slightly less neck tension. This, I assume is causing this to happen.