Hello, I purchased my first gun this memorial Day. It shot fine for about 300 rounds and started to jam: failure to feed, failure to eject, even type 3 malfunctions. I tried various ammo and mags, cleaned and lubed, to no avail. Seems to shoot better after cleaning but fails again after 20 or so rounds. I think I should get warranty service. Any recommendations as to which service center I should send it to? Thanks for any advice you can share.