Dry firing after 25 shots in 30 round mag.

[RC Collins]

I have a TM AK47 and I use 30 round star mags plus the one 70 rounder that came with the gun. With all these mags (lets say for example I'm using a Star 30 round mag) it dry fires after about 24-25 shots. I have to put a new mag in and the remaining 5 shots will drop out.
My questions are, is this normal? Can I fix this problem with silicone lube in the feed tube, or in the ends of the mags?
If so, is Motomaster Silicone Lube good to use, or is there a certain type of silicone OIL I should look for?. Also, is paintball gun oil better to use?

Thanks for any responses! :cheers: