I hired a Powernailer P50 to do my floors with, and I've been practicing on it with some spare flooring and a piece of ply. I've got it adjusted correctly to the height of my flooring, and the psi is right on the money of what the manufacturer recommends. I'm finding though that I'm getting a bit of splitting - do I have to adjust the psi, or is it just the nature of the solid hardwood and the fact it's only 1/2" thick (with a matching thinner tongue) that's causing the issue?
Sounds like it might be a poor grade used for the plywood core. With the Powernailer 50P it should not slit the tounges if it is set right. Make sure the gun is set right against the wood before hitting the head. Good luck.