Fusion Firearms XP PRO Update! Ammo Picky!?

My XP Pro won't run Winchester 115 FMJ reliably. I'll be forming a list showing ammos that are a go and those it doesn't like as time goes on(hopefully no other ones have issues). The gun is also suffering from issues when running the 10 pound recoil spring. Any ideas post them up in the comment section. The tests will continue...