It's hard for Internet experts to say whats wrong from one picture.  However since we are anonymous and don't have to account for our advice here's mine.

Most problems like the one pictured are due to inconsistent temperature. Lead has to be hot but so does the dipper mold and all, Mold too cool it cools the lead inconsistent.  I would heat up the pot, prop the mold up against it so heat transfers and brings the block's up the a nice high even heat then try it again

If you are bottom pouring might try switching to a dipper. If all else fails holding the dipper in contact with the blocks after you pour keeps the heat transfer even and lets things fill out nice.  Even though the metal has transferred  dipper adding to the mold heat will help keep the bullet liquid and able to fill out better

Boats

This just in.    My son told  me that one block fell on the garage floor  between day  1 and 2.   Could a drop bend the blocks?   

I'll try Mi-shooters advice,  but I think I found the cause.

-06

-06, the bullet picture is indicative of poor head pressure when pouring the melt.
* Scrub the mold cavity with Brake Cleaner, not alcohol ... when the mold is cold
* Heat the melt up to between 710-730 for that 335gr bullet
* Heat the mold up on a gas burner
* Mold and melt at temperature ... take a full ladle scoop of lead
* Tilt the mold horizontal - put the ladle spout tightly into the sprue hole - turn the mold vertical (spout still tight in hole)
*  Pour for 5 seconds with a nice puddle
*  If the sprue puddle frosts @ approx 5 seconds, your melt temperature is correct.  KEY ... If not, adjust temp accordingly 

Try it and let's see a bullet picture.  Make sure to include the bullet base - it should be 'razor' sharp

OK I'll add my two-cents. 
First check the mould to make sure it closes correctly. If it has been dropped and fell on an inside corned you may have raised a corner. Check to see that the faces are flat. Now that we know that the mould is OK wash it with good hot water and a toothbrush dry it right away and then clean it with break cleaner. Smoke the mould with a match or use some mould prep on it. If you use mould prep remember your not painting a barn door a light even coat will do. Now we are ready to try casting.
  You didn't mention what alloy, if any you are using. This is important different alloys will want to cast at different temperatures. For 30:1 lead tin I use 825 for 18:1 I am using about 750. If you are using an alloy that has antimony in it it is going to want to be on the cool side. 
  Now set the mould on the edge of the pot Make sure that the sprue plate is touching the pot, turn it on and walk away for 45 minutes or so. This will let the metal melt and fully come to temperature and if there is any moisture anywhere you will not be there when the metal pops from steam. 
  Now start casting. Cast anywhere 10 to 15 bullets before you start to save them it will take you that many for the mould to come up to a casting temperature that will give you good consistent bullets. Work on a good consistent rhythm, Make sure that you are holding the mould square and that the hole is directly over the hole in the sprue plate. If you tip it even a little you will get inconsistent pressure and your bullets will reflect that. 
From what I saw either you have contaminants on your mould, silicone can be very hard to get out, or your casting temperature is too low. 
The rhythm I like to use is hold the mould square when the sprue goes hard count to 3 and push, don't hit, the sprue plate open. and pop out the bullet.
As always your mileage mat vary.

40 Rod

So I used the following advice:

I set the alignment pins back a hair (MI- shooter was right,  it took some force)
I scrubbed with hot soapy water, let dry
rinsed with Brake cleaner

I could still see daylight through the bottom

I lightly sprayed  with drop out  and the light went away. 

I casted about 50 near perfect bullets at ~750 degrees  that were NOT shiny, but hazy finished.

not content to leave well enough alone,  I rinsed out the Drop Out with brake cleaner (the light reappeared)   the next bullets out were bright shiny and winkled  (still ~750)   After about 10 bullets,  I  just dusted the bottom of the mould halves with the drop out,  that blocked the light.  The bullets came out  perfectly shaped but hazy.  The bullets may be casting the shape of the graphite ??

I may tighten the mould handles down to see if I can squeeze the light out and see if that gets me shiny perfect bullets.  But I've enough bullets to kill some paper,  so off to the range,   

thanks to all who offered advice,

oughtsix

I pre-heat my molds on a hot plate and get good bullets right from the start.