jonskorepa
Not knowing anything about your casting technique but going with your statement that your bullets are not filling out, my first thought is the heat of your alloy and/or mould is not hot enough. I normally cast 1:20 alloy about 800 degrees and cast 10 throwaway bullets to get the mould up to temperature before starting a run of bullets. I get .1 grain variation casting 210 grain 32-40 bullets so I know I’m doing something right.

gentle men thank you for the advice and comments ill try warming things up a bit and see what happens need to cast next week with luck and creeks dont rise im in restaurent biz so one never knows. tks  jon

I cast up a lot few weeks ago outdoors with just below freezing ambient temp with a strong gusty wind blowing. Last time I cast it was 95 degrees.   That's 70 degrees colder outside were the mold was working. Had trouble at first with fill out under the sprue plate.

Had to slow my pace and leave the dipper on the sprue plate longer making sure the heat transferred well to the top of the mold.  Lot of different temp's working. Pot and lead was hot read off a thermometer. Mold was hot too but the sprue plate is thinner and spends part of it's time open not part of the same heat "sink" as the rest of the mold. It was just not staying hot enough to make sure the base of the bullet filled out well. Slowing down and holding the dipper longer made it turn out very good bullets with a low rejection rate when inspected after.

Lot of ways for the bullet to go wrong, alloy and cleanliness of the lead probably first but temperature is the next for sure. And a whole lot of variables working on actual temperature.

Boats

Cat, you forgot the most important factor...remembering which pair of teeth to hold your tongue between while casting!     All excellent points you brought up, and for those who cast only infrequently, it can be hard to remember which methods work for a particular mould and alloy!

David

I've been casting round balls for close to 50 yrs, started with a Dixie mold, made of curling irons I think, and never had much problem. When I first tried casting 410 g bullets for a 40/65 I found I had a lot to learn. Proper alloy temp, mold temp, flux, and timing. Also learned to use a Paul Matthews swirl and to give the bullet time to freeze before dropping it. I've heard and read varying opinions about how much to flux. Some people say flux only once at the beginning. I probably do it too often. I've had good results with a nose-pour mold, although I have a new base-pour spitzer mold that I haven't had a chance to use.
Lynn

Those standoff thermometers are highly questionable, IMHO.  I studied them at length when trying to find a quick way to determine the temperature of engine blocks we were gaging in the auto plants.  They have to be calibrated for the "emissivity", (real word), of the material you're looking at, to be anything like accurate. Just as some surfaces absorb radiation better than others, so some materials emit radiation (i.e. infrared) more efficiently.  So you would almost certainly get different readings off your mold, your metal, and your pot, even if they were actually at the same temperature, because each object has a different emissivity.  BTW, on the ones we looked at, the laser is just a targeting device. It has no role in the actual measurement.  

uscra112 is right about the laser thermometers. I have one and have checked it against a very accurate lab thermometer on several different types of surfaces. The difference varies, but not enough to matter when it comes to molten lead. However, they are extremely inaccurate when testing a shiny surface like the shimmering lead in your pot.
The best way to maintain a constant temperature in your lead pot is with a PID controller. It is a small digital computer that you enter the temperature you want and it maintains that setpoint.