thanks for the compliments. I did both of those guns myself. The gun with the red water plugs is 400 grit and all colt parts except rsp and bottom plate. I hand lapped the sideplates on a granite block up to 600 grit before riviting, cause you cant do it right with those rivits sticking up in the way.
The one with the spades is the beater I made from a colt jacket and an izzy backend. It is a post sample. The water jacket on it had been polished also to 400 grit, but I went back over it with a "fine" scotchbrite pad to tone it down a little so it wouldnt contrast to much with the glass bead blasted backend. I used izzy parts on it to preserve the original parts kit for something in the future at which time I will tear it down for the water jacket.
On the transferrable I used nitre blue on all the screws and small parts. It leaves a peacock blue, but at 600 degreese it is a no no for anything but the smallest, non structural parts.
The rest is oxynate 7, although dulite will do just as well. I could only get these two guns out of a batch of salts before the bronze on the guns killed the salts. So enough salts to do about 200 bolt guns did 2. Not to mention I had well over 40 hours in polishing the colt, its easy to see how these blue ones get expensive quickly.
Both of the guns also have nickle plated internals, cause thats how colt did it and after shooting and cleaning them you will understand that colt knew what they were doing. They just wipe clean and never rust.
I sincerely believe the colt gun is as close as legally possible to the guns supplied to argentina in the 20's and 30's. It is a little slicker than they originally were, but it is accurate in every detail. I would be happy to discuss these in more detail. Shoot me an e-mail or pm me if you need any help on yours.