Vivitar for Nikon (possible mounting problem)

[rvlvr]

Hi all,

Bought an NM Vivitar 200mm f/3.5 off eBay.

I love the mechanics and feel of the lens, but as I tried it on my D300 I couldn't really work the aperture ring, it felt like it was stuck. The problem does not exist with the D40x I have. I believe I might break something if I were to continue to use it on the D300, so it would be better not to try to mate the two again? Or is there a way to make the lens D300 compatible?

I gather all this has to do with the non-AI mount? Pretty stupid of me not to check on things before barging in, but as it sits pretty, well, pretty, on my D40x, all is not lost. (In fact I quite like the lens, the focal length feel somehow just right.)

I've attached a picture which, I hope, should tell at least you guys enough to verify the situation.