When you say expires, is that based on the date on your cert or including the 4 month extension?
If you applied to renew in time, you should get an automatic 4 month extension on the expiry on your ticket. That said, I’d still want the FLD to confirm they consider you have the extension.
To answer your question, rifles, shotguns, mods and any other pressure bearing part should be given to an RFD, plus rifle ammo. Shotgun ammo doesn’t require a license to possess, only to acquire, so you can keep that. I don’t rightly know whether you can possess primers and powder without a valid ticket or, whether like shotgun ammo, you only need it to acquire.