Casting is not difficult. It does require a few parameters be met... lead temp, mould temp, mould cleanliness and lead cleanliness. A few tips follow.
-I use a temp controlled lead furnace and a hot plate for my moulds. But I used a basic Lee pot for decades. They work fine.
-Set the furnace to 750 degrees F. The hotplate to, well, whatever it takes to bring the mould up to about 500 degrees F.
-Clean the mould before you get started with HOT water, Dawn dish soap and a tooth brush. Never, ever use anything metallic on the inner surfaces of a mould.
-Flux the lead, candle wax is good for this. Skim off the dross. Stir well.
-Get everything up to temp before you pour the first cast.
-After a dozen or so casts you should be getting decent fillouts. If the slugs are still wrinkly you are not hot enough or there may be something in the mould (soap or oil). Try putting the mould back on the hotplate for a bit (turn the heat up some).
-You may also need to "smoke the mould", do this with a candle, letting the soot of the smoke coat the cavities of your mould. Leave the fancy mould release sprays for the millenials and new age wannabee's, good old candle smoke soot is what you want here.
-In some cases (usually the larger calibers or those with lots of details) a "pressurized pour" may be needed. Do this by placing the furnace spout into direct contact with the opening on the sprue plate. You may need to "top off" the pour as the lead will skrink back into the mould and create a void at the base of the slug.
-Frosted slugs are indicative of a too hot mould. Wrinkly slugs usually indicate either mould contamination or too little heat.
-Once you get a mould "running", make as many slugs as you want....do not stop for culling or to size, coat, whatever. Just get your casting done.
-Powder coating is easy, but seems to be very dependant on the powder you get. I like Eastwood products. The "Ford light blue" works everytime.
-A toaster oven from the local Good Will or even a cheap one from Amazon will work fine. Use an oven thermometer to dial it to 400 degrees F.
-Powder coating works by virtue of static charging. This can be accomplished with a plastic container (look for the "5 inside a triangle"). Put the powder (small amount) into the container along with the slugs. Close the container and give it all a good shake. The built up static will charge the powder and make it stick to the slugs.
-Carefully pick out the slugs with a tweezers and place onto a silicone sheet (or even just the toaster oven pan) base down. Arrange in nice, neat rows.
-Carefully slide the tray of slugs into the oven and bake them for 20 minutes at 400 degrees F.
-Remove the tray from the oven and let cool.
-Size the slugs to whatever you need. A good powder coat will not rub or flake off, even when squashed with a hammer.
-You may need to trim the base of your slugs with a special tool (Noe makes one) if you find "flashing". Remembering that the base of the slug is all important as it is the "steering wheel" of the slug and must be kept uniform.
OK, that's about all I can come up with for now. Let me know if I have left out something or you have any questions.
Chris