I've had a Hoch nose pour 38/55 mold for nearly 20 years. A random conversation with a friend made me think of it and get it from the depths of my safe. I fired up the Lyman melt pot last night, cast 3 dozen, had 5 that weren't *total* junk. Tried again today with various lead temps as the PID control on the Lyman makes it easy.  720, 750, 780, with only a few keepers. If the base is flat, the bands are rounded, or only rounded on one side of the mold. If the bands are decent, the base isn't good, or the nose is bad, or combinations of all the above. 

Now I remember why it's been forgotten in the safe.

The lead is 1/20 certified alloy that casts very well for other, albeit smaller, bullets.
I heated the mold on the pot rim, tried more heat with a propane torch, all to no avail.
Faster pour rate, slower pour rate, the mold tight against the spout, still issues. 
I even tried pouring some with a ladle with the same less than stellar results.
I'm stumped. 
Any thoughts or suggestions? 
Thanks.

My Hoch nose pour mold want to be hot and run very fast.  I basically set the pot to 850 and cast as quickly as I can.  Once the mold starts to fill out fully the bullets will come out with incredible consistency in fill out and weight.

Chris.

No.

There's a lot of machinery on the Hoch nose-pour moulds and it all has to get up to temperature.  The handles have a lot of metal in them and the base-and-sprue plate sheds a lot of heat when it is swung out, as well.

Getting the temperature up should do it.  I've found that some moulds just need more or less use time before they finally start producing.  A couple-three less-than-satisfactory sessions and then the block metal seems to "season" (or something) and then it starts producing "keepers.".

cellergun
Just my opinion but I think your main issue is a bottom pour lead pot. I gave up trying to cast match quality rifle bullets with at bottom pour over 40 years ago. You might try casting with a ladle, you can use your bottom pour pot with a ladle and I'll bet the quality of your bullets takes a huge change for the better. As a parting comment, try the Lyman ladle, it's the best design out there.

I agree with RSW.  That mold will work a lot better with a ladle.  I hadn't realized that you are bottom pouring.

Chris.

No one has mentioned making certain the mould is clean. This has bit me in the butt before, more than once and the first time was actually a Hoch nose pour.

Holding medium heat to the cavity in the mold, more than a candle, low propane heat, watch for the surface to start to sweat. The heat will draw oil from the pores if it’s there. If that happens, it will be impossible to use a match or candle and have smoke stick to the area. If that happens lead won’t fill the cavity.

Ladle pour for the win.
Thank you for all the suggestions. 
The mold has been scrubbed more than once with carb cleaner and most recently acetone, so it's definitely squeaky clean, with no sweating from the torch while warming it up.  
I fired up my dedicated ladle pot this morning, tried running it at 725 and had a 70% reject rate. Tossed those back in the pot, ran it up to 750, let it stabilize, fluxed and started casting.
Why 725 and 750 instead of 850?
I can get it hotter with more control than cooling it down and I'd rather cast cooler than hotter if possible to prevent alloy deterioration.
I cast some bullets, have 42 that look great visually and a dozen culls. That's a reject rate of 20% which is more than I like, but better than the previous 70-90%. 
Some rejects were no doubt due to mold heat up, some were no doubt due to operator error while reestablishing my ladle technique and a casting rhythm. Hopefully the next session will be even better. 
Thanks again for everyone's help and suggestions.
Richard