I'm trying to paint a rubberized Hogue AR15 buttstock and while it's mainly going acceptably for rubber overmold, some parts of the rubber are are sticky and shiny. I let it dry for 16 hours, then put in oven for 30 minutes $ 200f. Still has sticky spots. I tried removing most of the paint with a wire brush and high purity alcohol and there's still sticky areas. When I try to fix them, it seems to only spread the stickyness.

What's going on here? Majority of the stock came out pretty good. I'm using rustoleum camoflauge spraypaint

Did you use primer first?

No. What kind would be appropriate for rubber?

Well that's the thing about painting anything rubberized or vinyl, you never know for sure. It is best to mask off a tiny bit and see what happens before going whole hog.

That said, I have used Krylon COLORmaxx Primer all 4 colors on a variety of materials for years and it has always set within 24 hours.

Putting any kind of enamel on rubberized or vinyl without primer will almost always turn into a sticky mess and it is very hard to stabilize it after the fact.