I shoot the sierra TMKs because hlthey were what i found when i wanted to try a 155 and they shoot very well in my rifle. load development wasnt difficult, they shot well at a wide range of depths. Some people say they only run 155s when rules dictate but for me they reliably have less drop and drift than the 175/178 i was using before with slightly less recoil. i have had good success shooting them out to 1k on steel, but havent had the opportunity to shoot groups past 300 yet