I recently purchased and used some Adcom 124gr FMJ in my argentine FM HiPower. Now, I've read that using +p rounds in a HiPower can stess it out and it then came to my attention that the Adcom I'm using is loaded close to "NATO" spec. Looking online, I've had pretty confusing answers about NATO vs +P. Some say they are close, others say they aren't. Is the ammo I'm using bad for the HP, or is the NATO loaded stuff fine? I'd imagine if HiPowers where used by NATO/affiliated members, the use of NATO-spec ammo wouldn't hurt them, right?

I have read that there are 2 different NATO 9MM loads.  One for pistols and one for SMG`s.  The load for SMG`s is supposed to be hotter than the pistol load but I dont know by how much.   The pistol load would probably be OK in a Hi Power.  You can find a lot more HP info here:
http://www.hipowersandhandguns.com