100-400 USD or so depending on specifics
100-300 USD
the serial number on your ruger P345 is located on the right side of the firearm directly beneath the slide. its a silver looking plate with an 8 digit number.
Take it to a gunsmith. You did not say what is wrong with it.
if you mean the air soft pistol then yes it can take both 0.12 and 0.43 plastic bb's
Moondog Industries gas fill O-rings from evike.com. Quick, easy, and inexpensive.
neither, also it doesn't matter which one is "stronger", if you have a a high FPS (strong), you can't play on fields
First off, it's "picatinny" rail. Secondly, no there are no aftermarket rails for that model that I am aware of. However, a competent gunsmith may be able to machine the frame to act as such.
if condition is good 4 or 500
Unknown caliber. Contact Ruger
Which one?
100-500 USD or so