Hi I am new to the forum. I just received a 1st gen p-3at as a trade. Today was the first day I got to shoot it. I like the gun but had at least 1 jam per mag. It would fail to eject the spent casing (still in the chamber) and the next round would jam into it. The spent casing would have a nick in it but would not eject. Ammo was federal american eagle. Is there anything I should check or look into. Guy said it had about 400 rounds through it.