I have a parkerized Remington 700 with very light spots of rust on the barrel. So light in fact, that it cant be seen except under a very bright flashlight or high noon sun. Can I use rust converter on the parkerized barrel to halt the growth and cover it up? The parkerizing is very dark almost black so the black converted rust wouldn't be visible, but I'm not sure if the rust converter is safe on the parkerizing since it too is a form of oxidization.

Does anyone have an input on the subject? or has done this sort of thing? I can post pics if nessecary but we all know what little leopard spots of rust look like.

Thanks in advance

It's hard to say.  Parkerizing forms a sort of crystaline phosphate coating on the outside of the steel, and it's definitely not a similar process to hot or rust blueing.  You might be good to go, I  personally don't know of any chemicals that will eat parkerizing away.  Not saying there aren't any out there, though.  I've never tried blueing remover on a parked peice.  

I'd say give it a shot on a small part of the barrel that's under the stock or otherwise covered up.

I appreciate the response. Next time I have my action out of my stock I'll try it out. After a little research, I might try just a little dab tannic acid, which is the active ingredient in rust converter that does the converting.

1) Corrosion X to eliminate, or naval gelly (ph acid) to stop corrossion. Clean and Oil.

Don't use a Rust Converter because it forms a film of "converted rust" that is 'paintable'.  You don't want that coating.

2) You might try Ospho or similar phosphorus acid ( concrete etcher at Lowes is usually phosphoric acid).  ex: http://www.wmbarr.com/product.aspx?catid=103&prodid=221

When you treat steel or cast iron before you paint it, you can use phosphoric acid by wiping wet pads or brush on the phosphoric acid - it eliminates any rust - leaving a light paintable phosphoric coating

depending on the product, you then rinse (in water, ironically) the acid off and quickly blot dry it  to prevent flash rust.  This might eliminate any light coating (whitish) of the ph acid, but then OIL it immediately.

In the case of your barrel, you could dap a wet rag of phosphoric acid in the immediate area of the rust, wipe off (it will leave a phosphoric 'coat' to protect the metal), and then oil the crap out of it to prevent any flash rust.

I'd test under the barrel (against the stock) to see if you get discoloration, if so you may want to take the barrel off and do the whole thing for uniform color, or rinse all the ph acid off and use a hair dryer to dry immediately after the rinse.  Use nitrile gloves so you don't get acid on you, and don't get oil/salts on your rinsed barrel.

It doesn't sound like you have a big problem, you could just dab back and forth some ph acid in the rusting area and then wipe off with water towel, then immediately oil.

my 2 cents.

parkerizing itself doesn't form any rust prevention - but it allows oils to accumulate in the "crystallined" areas to prevent rust.