" are they are same in the 500-590-590a1 etc ?? "
Yes. Identical.
The difference between models is really nothing but marketing. They are in fact the same gun.
The mag cap is different, the 500 have a fixed one and the 590 a removable one.
Thanks what about the 88
and plastic trigger guard (vs metal) , plastic safety button (vs metal) , thinner barrel thickness ... rest is about the same.
88 uses the same bolt. Main difference from 88 to 500 is the trigger group and receiver (safety location) and the pump (88 is a pinned one piece pump).
There's a few small differences like the 88 isn't tapped for a rail on the receiver.
Pretty sure the barrel thickness is the same until you get into the 590A1.
" The mag cap is different, the 500 have a fixed one and the 590 a removable one. "




























