I disagree about its being sentimental. The grandfather may have won it in a card game, or taken it as collateral for a loan. I have done both with buddies when I was in the military. Guitars, watches, cameras, and stereo equipment mean nothing to me, so I wouldn't bother mentioning them to any of my heirs.
Being stuck in a shoebox in a closet indicates to me that your grandfather didn't have any attachment to it either. He obviously didn't value it.
If Lugers don't do anything for you, why keep it? It's not like you and your granddad have any shared memories of it.
I still have the JC Higgins bolt-action single-shot .22 that my mom & dad gave me for my 13th birthday (1963). I took it out last week and cleaned it up. I have a couple boxes of 'High Velocity' .22's that I want to get rid of. I plan on blowing them off when I'm alone at the [indoor] range. I'm not into .22 rifles anymore (sold my Winchester 52C some time back) so it doesn't really have any monetary value. But it's what my dad taught me to shoot with, and it was fun to plink with.
