The first thing I would do is clean it really good. If I get any kind of oil in my Lee molds they are harder to get working again, than any of my other molds. This makes it hard because you have to lubricate Lee molds to keep them from wearing out.
Another thing I have noticed about Lee molds is that they like it hot. I turn my pot all the way up and don't have any trouble, except that I have to wait longer for the bullet to harden so I can cut the spru. I usually just cast with two molds and let one cool while I fill the other.
Another Question.
A friend of mine got a 6 banger mold from Lee in the 158 gr RNFP design. It had a longer skinney nose. He then got a second one so he could cast with two molds at the same time. It had a shorter, fatter nose, but was the same bullet number. I got one (same number) because both of those bullets worked great in my gun and When mine came it had the shorter fatter nose and a bevel base also.
Mine didn't shoot worth a darn in my gun and I wrote to Lee and complained. They said, send in the mold. I did and when I got it back the bevel was gone. They ground it off. The bullets weigh 150 gr now, so I lost 8 gr of bullet. It now shoots great though so I didn't complain too loud.
What is your mold like? Any of the above or different still.
Sixgun