Same deal here .223 , I havent shot alot of different stuff thru it because I found cheap ammo that shoots well thru it. out of the cheap stuff Remington UMC , Winchester White box and some PMI stuff the Remington UMCs FMJs shoot the tightest 100 yard groups .
This was a 100 yard group using Remington UMC 55gr. FMJs on 1" squares , I have this zeroed for 200 yards so its a tad high on the target . Not to shabby for cheapo ammo but I had to rework the trigger to get it to this , you could almost cover that group with a dime