Granpa, with .380 ammo (any .380 ammo) being as scarce as it is, I am limiting any future testing to my home-grown reloads. I gotta tell you, I am so worn out with this Magtech mess that I may just go back to my Daisy BB gun. I would not shoot Magtech +P period until we know more and yes, bullet setback could have been a factor as well as the integrity of the gun itself. I have no desire to find out. I have never fired Magtech, have none to test (nor would I). As for BB it's been fired a lot both in the P3AT, the LCP, and I have tested a few rounds in my P380 with no ill-effects. I am comfortable firing it in the P380 in limited quantity. Ruger on the other hand says no to any +P in their LCP, Keltec has never endorsed +P in thei P3AT, and for the conservative risk taker that should be enough if you own either a LCP or a P3AT - don't ask me about Seecamp or NAA - not familiar with either. The P380 on the other hand is a stronger platform than the P3AT or the LCP and I would not hesitate to rely on BB for carry - but that's me, your mileage may differ. In other words, test a few rounds, make sure it functions and stop. If your gun will feed Gold Dot, it will feed the BB JHP.
Keep in mind BB is potent stuff but it is not necessarily heaven's gift to .380. There are other choices, all of which are non-Plus P and could just as easily get you out of a SHTF situation. I am however impressed with the BB fmj flat nose and the BB hard cast. I have seen some serious penetration specs. But in the end, who knows what a bullet is going to do.