I always put the most work into 300 yard ammo. You loose the most the fastest there. At 600 you only loose it one shot at a time. At 300 you loose or gain 10 at a time and its much less forgiving than 200
At Perry on the 300 yard line I shot a 98 in the P-100, a 99 in the NTI, and cleaned it in the six man team.
Also shot a 99-5x at 600 in the P-100. Shot a 9 on the first shot and cleaned it from there. Would have made the cut if I could shoot on my feet. Ordered a SCATT trainer and will have to start putting some serious effort in it.
Also cleaned a couple of 300 yard 10 shot strings at Atterbury including a 100-7X. A little easier there with sighters and not having to stand.
