I got into the precision marksmanship game a little over a year ago. For a short background, I'm shooting a factory Remington 700 in a magpul PRO Chassis with a Leupold Mk4. It's a .308. I've been shooting Federal Gold Medal Match (168) this whole time, and today to Hornady ELD-M (168). The first 5 group (pictured below) with ELDM was less than impressive. This was fired at 100 yards.
After letting the barrel cool down, I went back to my stash of Federal, and fired another 5 round group (Pictured below). This group was also fired at 100 yards. This is the type of grouping I am accustomed to.
I failed to take anymore pictures, but I let my partner shoot 2 groups and he had similar results to mine. However, as the day went on, we continued this and the groupings on Hornady tightened up significantly.
I understand that certain guns prefer certain ammo, but for the life of me I can't figure out how the groupings of the Hornady tightened up so much. Typically I would blame myself, but with the Federal grouping right, and my partner getting the same results, I'm hesitant to blame myself. Is there any science to explain why the group would tighten up throughout the day?
After letting the barrel cool down, I went back to my stash of Federal, and fired another 5 round group (Pictured below). This group was also fired at 100 yards. This is the type of grouping I am accustomed to.
I failed to take anymore pictures, but I let my partner shoot 2 groups and he had similar results to mine. However, as the day went on, we continued this and the groupings on Hornady tightened up significantly.
I understand that certain guns prefer certain ammo, but for the life of me I can't figure out how the groupings of the Hornady tightened up so much. Typically I would blame myself, but with the Federal grouping right, and my partner getting the same results, I'm hesitant to blame myself. Is there any science to explain why the group would tighten up throughout the day?