Or is it possible.  About 1/2 the Krags I see have a dark red/brown color and shinny gloss look.  I belive the look is from soldiers rubbing gun oil over the stock and 100 years of time.  What ever it is I like the old glossy 'look'.  The other 1/2 of the guns appeared to have been cleaned at some point.  They look lke any other old gun on the rack.  I am looing for a nice 1902 ish rifle with the 02 stock and 02 sight and 02 serial number.  I found one locally and everything is perfect, good bore, crisp cartouche - BUT !! at some point some one improved it with a good cleaning.  I could hold out, or I could give this orphan a home.

Is there any way to get that old look back?  I heard tricks like Mystery Oil or Liquid Gold and lots of time and rubbing.  Note this is not a preservative, it is to replicate what we know today is bad practice of using petroleum product on a wood stock. That is for the gloss.  Then there is the color.  Were these stained?  The unmolested guns have a deep redish tint.

Can these ever be made to look right again?

I work on a lot of stocks from general cleaning to restoring and matching varnish and aging colors.

I have used Howard's Feed and Wax for years for cleaning and some restoration work but this will not darken the wood. I use Boiled Linseed Oil when I am trying to restore the aged look and fix stocks that needed some staining initially.

We all have our secret ways of working with our mil surp stocks. The old adage of "Do No Harm" plays well with this kind of work. Strong petroleum products and some chemical cleaners will ruin nice wood so be careful.

If you have a specific problem, post some pictures and let us see. We might suggest a certain approach.

Good luck and keep us informed!

Honestly, with the wide variety of different colors or appearance of authentic, aged, military configuration Krag rifles and carbines, I don't think you need to reproduce the exact original stain used 120 years ago. I have a number of Krags, as do many others on this forum, and most of them, side by side, look different. I use staining to try to best match the specific firearm stock I am working on for consistency of the different parts. I hate seeing a Krag that has a dark stock and a light hand guard. I have actually passed up purchasing some nice Krags because they appeared to be mismatched in their stock parts. That's a dead give-a-way that it has been pieced together at some point.

So, you don't have to reproduce the original color of stain to be authentic or correct.

Others can chime in to help. I have not studied the original staining process as much as some other Krag-philes, so, your question may be answered better by someone else. I just wanted to add my 2c worth of experience!

Was it a 'used' toilet seal ring or a new one?
I'm sure that a 'used' ring would have some interesting added ingredients! 

(Sorry, I could not help myself).

IIRC - The main ingredient (on a new toilet seal ring) is Bee's Wax.

Bee's Wax is also a large component part of 'Howard's Wax & Feed' and many other antique wood polish and final finish recipes.

Mixtures of Bee's Wax or Carnauba wax are benign wood treatments and nicely restore luster and a slight sheen, when hand rubbed and buffed with a soft cloth.
They help protect wood and are easily thinned or removed with turpentine, mineral spirits, or a turpentine & linseed oil mixture.

Not sure if they still are, but toilet ring were made of bee's wax.

I used Birchwood Casey's walnut rusty wood stain. It’s water based and the first coat looks terrible but it evens out after a few more. I used it on my ‘03 Springfield sporter [21 inch bbl] rebuild. But this was a sanded and modded scant stock. Turns out nice and reddish. BUT...I would never sand an original stock on a Krag or Springfield unless it was already buggered up and the cartouche was already gone.

Clean it first, have found mineral spirits and cheese cloth or the gray scotch brite pads work well for this.  Apply the MS and rub GENTLY on a small area and wipe off with paper towels.  Dirt and grime are not additives to any finish I know of. Once satisfied it is clean, or as clean as it will get, apply a 3/1 mix of BLO and MS liberally and rub in for 5-10 minutes and wipe off excess. After a day or two apply again but only enough to wet the stock and rub with your bare hand until it feels warm.  Wipe off the excess and repeat daily until you are satisfied with the finish. This will reproduce the shiny finish you see on some stocks, but gloss will depend on how smooth the stock was to start with.  If the stock is extremely dry you can start with a 2/1 mix of BLO/MS which will penetrate better.

I clean my oil finished wood stocks with a oil scrub.

I cut raw linseed oil with turpentine to a 20%/80% mixture, then scrub the wood with a very fine scotch-brite pad.  Remember, you are trying to lift the dirt and grime out of the grain, while not removing any wood in the process. 

Work in small sections at a time, then wipe the oil and lifted grime with a clean cloth.

Once you are finished, wipe the stock down again with a cloth moistened with turpentine, allow the stock to dry for a day or two, then repeat.

When the stock is as clean as you want it, rub in a few coats of linseed oil.

Original 1903 stock after an oil scrub.  After cleaning it up, the handling marks from the individual that it was issued to became visible.