I have been using them ever since they came out for hog hunting. I just bought the whole rack from the clearance Isle at Walmart for 5 dollars a package. They are a type of conical with an expanding base as such I believe the loads you will find good accuracy with will be limited in charge to under 120 gr personally after trying a number of loads I found good accuracy with 90 and 100 gr and acceptable accuracy with 110gr of BH, after shooting them a while I settled on 100 gr BH as my hog load, I have taken 2 boar with it and the 100gr load both opened well and gave complete penetration in a 240 pound hog. My feeling about 150 gr loads is they only add to recoil after about 135 gr and only a few guns show any accuracy at that heavy a load plus the fact that the point of efficiency is about 110 gr. Lee