I recently picked up a scar 20s chambered in 6.5 creed and am having multiple popped primers with two different kinds of ammo. I cleaned the rifle very well before taking it out. I fired s&b 140gr fmjs first with no issues for about 15 rounds and then started getting multiple popped primers. I also tried berger match 140gr with every shot doing the same. Has anyone had this issue before? I don't think the ammo im shooting is crazy hot or anything. Any help would be greatly appreciated. Thanks.