I am far from a casting master, but I have always gotten good bullets, with some astounding accuracy, so here goes, and If I am incorrect, someone will surely correct me. I always cast very hot, as hot as my Lyman pot will allow, probably 800+ degrees. Pre heating your mold is very important. If the mold is too much cooler than your alloy, it will harden before filling out. I believe a cold mold causes 90% of all problems with fill-out. Lubing the mold is good, but don't over-do it, any lube in or around the cavities will cause pits and wrinkles. Over-lubing can leave burnt deposits in the venting grooves, which can cause problems, keep the vent lines clear. Unless the lead you are using is pure soft lead, you probably won't need to add tin to make good bullets. For muzzleloaders, soft lead is usually the best, (just to confuse matters). For most other bullets, car wheelweights can be used with good results. Basically, get some more heat out of your pot, get the mold clean, and get it hotter. Casting is fun, and very rewarding once you get the hang of it. Hope this helps.