Pushing in the slow jets

I'm attempting to finish this carb rebuild on my '80 650c but I'm puzzled by the slow jets. These size 42 jets are the ones that get pushed into the carb body but they don't seem to want to seat properly... meaning, they aren't in all the way.

So my question is this:
Do I need to man up and push those suckers into place? Should I lube them first?

I don't want to apply too much pressure and risk damaging them.
... and to answer the most obvious question - Yes, they are the correct size for my carbs.

Thanks!