That's what I said. 4506 is a 5 inch barrel like the 1006 and almost as expensive.
The 4566 is a "commander" length barrel (4 1/4 inch) with the same size frame as 1006/4506.
The 4566TSW models are ending their service life with some agencies and can often be found for $500 or less.
Same grip size and feel. Same manual of arms.
Much cheaper training/practice ammo.

John