22 Jets are fun and if you keep chambers clean and keep the velocity down on reloads they work well. The fire breathing Remington factory loads however were problematic. I bought some PPU Jet ammo right after I got my 6"53 and never had a problem with it.
Bullets I have fired .222, .223 and .224 bullets in mine. But I made a .223 sizing die to fit my bullet sizer and run .224 bullets through it. Anyone with a lathe can make a sizer if they buy either a .222 or .223 chucking reamer.
BTW I then came across thousands of pieces of never fire Remington factory brass if anyone needs some.
Also if you don't have a bullet sizer a machinist could make a die by drilling and reaming a 7/8x14 grade 8 bolt to .223 put a sight taper in the bottom then make a ram to fit in the ram of a reloading press and press .224 bullets up through it