Re bluing your P14 using a kit like that mentioned by Toby will certainly be worth while.
Applying the chemical blue is straight forward and very easy.
Preparing the surface to recieve the blue is everything.
The better this is done the better the end result will be.
Rebluing your Martini will severly reduce any collector value if your considering handing it on to family as a heirloom/collector peice.
The value will be retained only if it's in original condition and for older rifles like this the worn patina is what will be looked for.
I'd just keep it well oiled or if your storing it for any lenght of time I'd pack it in grease.
Here's some information on the calibre you mentioned.
5.6x52R and .22 Savage High-Power
Have a look at these posts and see which one matches your Grandads Rifle.
BSA Martini in 22 Savage Hi Power in Miniature, Rook and Cadet Rifle Forum Forum
Cheers
Pete
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