First time casting bullets and I'm wondering,
Is a lead thermometer useful or necessary, should I get one?
Are Lee aluminum molds difficult to fill properly?
Are the steel molds inherently easier to use?
Can I just lube and shoot at less than 1600 fps?
With the 160 gr the lack of fill is like bug tracks under tree bark, will they shoot?
I'm using
Lee bottom pour furnace
Lyman .309 160gr gc aluminum mould (poor result)
For 308win and 7.62x39 bolt
Lyman .311 130gr steel excellent result
For 308win but mostly 7.62x39...
Rcbs .225 55gr gc steel excellent result
For 222rem
buy a cheap little hot plate so you can preheat your molds, saves a lot of time. also make sure to do a really thorough job of degreasing the mold blocks before you use them. then take a bit of sandpaper and "break" the edges of the sprue plate so it doesn't have any burrs or rough edges. get some synthetic 2 stroke oil and use it very sparingly on the pivot pin and alignment pins, don't get it in the cavities. you can use powdered graphite on a q tip to coat the cavities, it helps release the bullets.
you can use a cheap thermometer to help you figure out where the sweet spot is for casting cadence and bullet diameter.
aluminum blocks heat up faster and cool faster than cast iron blocks. once you are at casting temp, no difference.
lee aluminum molds are generally good but you must be gentle with them, keep the bottom of the sprue plate clean of lead buildup, and do not overtighten any screws.
water drop the bullets out of the blocks if you are using wheelweight alloy for harder bullets, keep the splash zone well away from the pot.
go to cast boolits.com for info on lube/powdercoat/ shooting bullets as cast. tons of experience and knowledge on that website.
bullets with flaws will disappoint you with less than stellar results, especially out of a rifle.
good luck, you may not get perfect bullets the first time, but don't give up. after a few sessions you will quickly learn what works.