You did not say what Para model and which mags you are using. I work with the P-16 model a lot and what I've found is if you bend the front of the top coil on your spring upward this will help keep the front of the follower up. I use Grams Engineering base pad kits in my mag tubes, I like the extra capicity they offer and the spring used in the kit is of very good quality.
Regards,Bob Hunter. www.huntercustoms.com
The slide stop is rising up and locking the slide back with a round left in the magazine?
Dremel or drill a very slight dimple in the end of the slide stop for the plunger detent to engage while the slide stop is down all the way. Then it will only rise up to lock the slide back when contacted by the magazine folllower.
If yopur problem is with P16-40 don't file away anything. Cause of problem is that the front of the magazine follower is tilted UP TOO HIGH. This lowers the rear of the round & allows the slide to pass right over it without picking it up. Disassemble the magazine. Bend only the top coil down. All will be well.