DK wrote:
If you'll tell us the model number, we'll have a better chance of
helping.
--
Steve B.
New Life Home Improvement

The air pressure the OP is running would be nice to know as well,
along with the materials being nailed.

It's a Model FN250A, and even when I bump up the air pressure to
100-120, it still doesn't penetrate all the way through the pine
window jamb into a 2x6.

You could try spraying the clip of nails with silicone before putting them
in the magazine. Might leave some residue on the lumber though.