About the best I can recommend from personal experience is a Savage MK II back in 2013. I tweaked the trigger, scrubbed the barrel with JB compound and bedded the action before I ever took it to the range. I then vetted as many kinds of ammo as I could get my hands on using 10 shots at 50 yds from a cleaned dry barrel. Lotta cleaning! Took several days to get through it all. Here's a link to the actual range report thread
Link. I tried to be as scientific about it as possible. A handful of ammo types shot IMHO very well, for such an affordable rifle. There were some bad choices as well, mostly being the cheap plinking ammo types.
Here's the net resulting 10-shot, 50 yd groups measured CTC:
T8-4 Eley Tenex <.389>
T5-4 SK Standard Plus <.422>
T6-1 Winchester Subsonic HP <.493>
T2-1 CCI Standard Velocity <.524>
T7-4 Eley Black Box Match <.526>
T9-1 Federal 900B <.538>
T4-2 Remington - Eley Target Rifle <.547>
T1-1 Aguila Golden Eagle Target <.591>
T4-1 PMC Match Rifle <.631>
T7-2 CCI MiniMag 40gr <.777>
T1-3 Aguila Match Rifle <.789>
T5-3 RWS Target Rifle <.801>
T3-3 Fiocchi MAXAC <.816>
T7-3 CCI MiniMag <.862>
T5-1 Remington Yellow Jacket HP <.868>
T2-4 Federal Premium HV Match <.886>
T4-3 Remington Subsonic <.894>
T7-1 Remington Govt Match <.940>
T8-2 Federal Red Box Bulk (Sorted) <.953>
T6-3 Remington GB Bulk (Sorted) <.973>
T1-2 Aguila Match Pistol <1.02>
T6-2 Winchester M22 Bulk (Unsorted) <1.108>
T8-3 Federal UM1 <1.236>
T2-3 Federal Champion 40gr (Unsorted) <1.132>
T2-2 CCI Stinger HP <1.141>
T3-2 Federal AutoMatch Bulk (Unsorted) <1.142>
T1-4 Aguila SuperExtra Standard Velocity <1.444>
T8-1 Federal Champion 36gr (Unsorted) <1.472>
T6-4 Remington HV <1.497>
T3-1 Federal Premium Target <1.716>
T4-4 Remington Viper <1.76>
T5-2 RWS Subsonic HP <1.978>
T3-4 Fiocchi SuperMatch SM320 <2.156>
T9-2 PMC Target <4.387>
The article is a good read with individual target images. IMHO. best bang for buck, easily obtained ammo that doesn't break the bank was the SK+. CCI SV did well also.
Hoot