Well, I ended up purchasing and using the WRONG primer. In a rush and semi-panic, to get the metal parts primed in my garage before the temperature escalates into the 90s (which it is supposed to do starting tomorrow), I purchased a can of Rustoleum Rusty Metal Primer (for the ultimate finish on heavily rusted metal, which didn't register with me when I looked at the bottle in the store that this primer might actually produce a rusted metal effect.. Duh). I was thinking it was going to produce a red rust color, not a rusty texture in addition to that. It was the only red primer that I noticed on the shelf at Ace Hardware.

Now my Tiger's metal parts look like they have been lying in a field somewhere for the past 66 years. They are covered with a textured coat of what looks like surface rust. I was going to buy just regular gray primer, but no, I saw the red color and decided to try and get a red primer like the Germans supposedly used on the real tanks. Now I have a good start for modeling a Panzer wreck..

If you ever want to paint a model so that it looks like the entire tank is covered with surface rust, then this is the stuff to use!

Hopefully, I can salvage this screw up by airbrushing over top of the rusty metal primer with Tamiya Hull Red Acrylic or something equivalent. I guess I will try to sand the gun barrel and muzzle brake a little with #800 grit sandpaper first before I shoot the Hull Red on it using the airbrush. I really do not want to have to strip this rust primer off the parts and start over again from scratch.

I don't have a paint mask yet, so it was loads of fun trying to hold my breath and run in and out of the garage between sprays. At least I was able to have the garage door fully open while I did all this crap. I was spraying with the parts laid out on top of a flattened cardboard box, which was sitting on top of an old table. Even so, I ended up getting some of the red primer on the bottom of my shoes, though I don't really notice any on the concrete floor of the garage.. I wore old worn-out shoes, so that wasn't really that big of a deal. But it proves that these rattle cans produce a large amount of over spray.