I have been working hard to get my Mossburg model 'L' ready to rust blue. The rifle was pitted in many areas. I was able to file out most of those areas but I was wondering what to do about the areas pictured below. The first one looks like the previous owner used a chisel, rock or something similar to remove the barrel pin. Any decent options to fix this? The second one baffles me a little bit. it looks like it was rust etched. I tried filing it out but it didn't work. Its weird, the area is completely smooth, no divot. I have contemplated leaving it as is but I'm worried that it will show up when I blue it. Thoughts?

Well, keep polishing.

Start with 180 wet & dry paper with kerosene or varsol. Work up grades one at a time until you get to 400# or 1000# or whatever you plan to finish at. Wrap your paper around a file or a hard block. If you have an old 1-2-3 block that will work. Make sure that all your polish lines are nice and straight and are going in the same direction. No cross hatching. You can finish your polishing with red scotch brite if you stop at 400# wet and dry. It will soften the finish. Keep the lines going the same way on both sides too.

99% of good bluing is in the polish. I used to use a belt sander to do those flat sided receivers when I did bluing.

This is what your polishing lines should look like. Make that !


Gunsmith Rod Henrickson Polishing by Rod Henrickson, on Flickr

I prefer mold maker stones to paper for the majority of the metal removal. They cut fast and if use correctly do an exceptional job. Really deep damage I usually TIG first. I finish polish to at least 400 grit using paper and oil, run over a very fine steel wheel at a low rpm and you should see no polishing lines when complete.

I hate mold polishing stones.....can't stand them

Well I respect your opinion after having seen the work you do Ted. Why is it that you hate them? I use quite a few of them in addition to files, hard stones and paper.

Steve

Being a moldmaker I have stoned a lot of EDM and cutter marks out of mold cavities

On 16 to 32 cavity molds you might spend weeks pushing and pulling stones of various grits

They work well but stoning is at the bottom of my list of enjoyable time spent

These days we use ultrasonic more and more with ceramic stones

I suppose there is no reason to not like them but we just don't get along

I haven't really started to polish yet, but all of the advice here is greatly appreciated. I am still worried about the bottom photo. I used 150 grit to see if it would sand out, but it almost appears like a permanent stain that is sunk into the metal. Again, not sure how to proceed. Do I ignore it, or is there some way to get it out?

That looks like a hard spot in the steel. Possibly a fault in the steel. That material was forged when Jesus was potty training so it could be anything. It could also be an area that was spot hardened for some reason. 99 Savages have that same problem right where the lucking seat is in the action. As long as you're rust bluing you shouldn't have to much in the way of color problems. Caustic hot bluing on the other hand would not work out to well.

Have very similar strange 'stains' in the metal on both of my original '92's in 44-40, neither are in the same area on the actions. Etching didn't change anything, nor did sanding and polishing. It is barely visible after rust bluing, but ruined my plans for case hardening, as that was the original finish on both.
I think you'll just have to suck it and see.

Cheers.

I would think that a color case would hide that sort of crap? No ?