I have a mossberg 500 persuader 20in version with a factory heatshield on. It is in blue finish. and i would like to change it to a parkerized finish since the blue finish is getting scrathed up. I would like to have the barrel, heatshield, magazine tube, and if possible the outside receiver to be parkerized. I have couple questions..I would also like to drill and tap the receiver to put a rail on so i can mount a holosite on it. I guess my 500 is too old and is not pre drilled.  :(

1. Can this all be done? how much is a rail?
2. Anyone know of any good places to do it , any in so cali? If so any prices
3. can the receiver be parkerized , or is it only the barrel and magazine tube?

as you can tell i'm new to this stuff so please bear with me. please contact me [email protected]

The receiver is aluminum which can't be parkerized.  It could be coated with a bake-on coating that looks like parkerizing.

These coatings can be bought from Brownell's Gunsmith Supply, who also carry shotgun mounts and other accessories.
http://www.brownells.com

For a parkerizing service, buy a copy of Shotgun News at the magazine rack and look in the gunsmithing services section for companies that offer parkerizing.

Having the receiver drilled and tapped can be done by most any good gunsmith.

Pricing on all this depends entirely on who's doing the work.