Rimfire bolt action
Had the same "bug" a few years ago so I bought me a Marlin 980V...I paid less that $200 for a new one and it is superbly accurate even with bulk ammo. On a good day (no wind and when I am on my game) I can hit a business card sized plate at 100~125 yards with some brands of bulk ammo with it. Then I got lazy and started to get interested again in my Semi-Autos...(no bolt to cycle)...so I don't use it as extensively as I used to. Over the last two years my 10-22 and a Marlin 60 have been used more, but there is no doubt that teh 980V is the most accurate...probably because it has a tigher chamber and a bull-target barrel.
I set up my steel plate on a cable---shooting into a sand hill and using a high power scope. I can then see the misses/strikes and correct my aim accordingly. This allows one to quickly determine just how accurate that the ammo is... I used a wide variety and the best was Remington Golden Bullet--of all things.