Nice looking rifle, I recently purchased a like new, used SR15 Mod 1 and it is great. In fact I just got back from the range with it an hour ago. Really cycles well, light weight and soft recoiling.
I have an Aimpoint on it now, but looking for a LPVO for it, leaning towards a NF NX8.
As far as ammo, I have ran 55-77 grain through it already, accuracy, is good, on par with my LMTs. It likes Sig 77 OTM, an ammo I recently tried and is look real positive for me.