There are all kinds of alloys that are popular, some involve mixing solder, wheel weights (WW), and lead. I reload straight WW in my 44 Mag carbine and SW29. I get some leading, but just consider it part of the cleaning chores. I cast a Keith 250 grain SWC which I resize to .429 and lube with 50%Alox-50% Beeswax. Many others use their own favorite mixes of lube or make their own. There are probably better choices for the high heat area where I live. You may want to trade the pure lead to other shooters for wheel weights or something else. A 250 grain bullet gets you about 28 bullets per pound of lead, since there are 7000 grains to a pound.
I can't advise on what size mold you need for the Marlin, or what size of re-sizer you'll need.
Yes you can use the cast iron ladle, but you may want the convenience of a smaller ladle that will allow more control. It looks like a little egg with a spout on the bottom. I've done both. After you start picking up all the lead splatter and feeding it back into the pot, you start wondering why you're so sloppy with that big ladle. Also wear leather gloves and a face shield. Wearing boots with pants over the outside is good too. This is important. A shoe full of hot lead is no joke.
Yes, you can use a Coleman stove, but you will not be able to melt real big batches of lead, or it will take a while. I've melted lead on a kitchen burner but now I keep food processing tools away from lead processing tools. When you are using your Coleman stove make sure you keep the wind off the burner and pot, or you won't get the heat you need. Wind can steal the heat. An old turkey frying propane heater or a plumber's furnace works well too. I make a tube out of sheet metal , or a big tin can around the pot to keep the wind off the pot. I use an old long handled slotted spoon from the kitchen to skim off the dross, floating steel clips and other trash. Once the lead is liquid I give it a good stir, skim off the junk, and then put a bit of wax on the molten lead and give it a stir. It will smoke a lot so keep a match or lighter handy to light the smoke. Stir the wax in while it's burning or smoking. Skim off any crud with the slotted spoon. The lead will then be shiny and you can put it into your ingot mold. An old muffin tin works well, but I've used aluminum ashtrays, or the concave bottoms of aluminum soda cans standing upside down. You can even make molds out of angle iron. Don't cast ingots too big, they are hard to get into the pot. I like to leave some lead in my pot when I'm done casting, as it is easier to get melted next time you want to cast. This 'heel' will melt more quickly, and then you can fed the ingots into it.
Melt all the DRY wheel weights in one batch and cast them into one pound ingots. You want to mix up all the lead so you get a uniform alloy of about the same hardness. Remove any wheel weights that might be zinc. If you can't scratch it with your fingernail, it's probably not lead. If it's floating on the lead alloy, it's not lead. If you get zinc mixed in with your batch, it will ruin them for bullets. You could still make fishing weights from them , I guess.
Be careful with anything wet around molten lead. Introducing a wet chunk of lead into a molten pot of lead will cause the lead to leave the pot, and head right for you. Even a big live bug in a bucket full of wheel weights can cause an eruption.
Mark your ingots when they cool. I put a WW on mine with a felt tip pen or use a small chisel to make a crude \/\/ \/\/. You will forget if you don't.
Well, that's enough for now. Somebody else's turn.
