HP rifle casting temp

[DrewTenney]

I've started casting .309 170gr boolits for my .308, I am getting a lot of marblization in my boolits. Will cast perfect in .452, then like **** in my rifle moulds.. temp issue? Mould temp issue?? What are your thought gents?? Casting around. 750-810 degrees, 100% WW.

[BABore]

The mold's not hot enough. Correct by preheating and casting tempo, not by increasing alloy temp. Also check mold cleanliness.