I recently bought a second hand Saxonia Big-valve 50 BMG rifle. It came with a bunch of Igman 699gr. M33 ammo. With this ammo the rifle shoots 6-8 MOA and even worse with some military ball of unknown brand. I have ordered a reloading kit and match grade bullets but haven't received it yet. The muzzle brake is tight and in-line with the barrel, the Picatinny rail is machined into the receiver and a Zeiss 6-24x56 is mounted into a 3-ring Optilock. What's your opinion? Do I need to wory?