Re: new neos old ammo (first post, too)
Nice Neos! I have around 8000 rounds through mine and it is still running strong. I doubt the ammo is old enough to have issues. After my grandfather died we found. 22 caliber ammo that was upwards of 55 years old. It shot fine but we did find that the lead had softened a bit and would cause some leading issues after a hundred or so rounds, then again it could have been the lead was just softer back then.
I have run every brand of ammo that you can imagine through my Neos and haven't had trouble with any of them. I have found that after 500 or so rounds in one session the gun starts to get really dirty and will choke occasionally when chambering a round. As soon as I clean it back up its good to go again.