Have you tried a web search? Local Library? Do a web search on Harrington and Richardson Books and you will find some sources.
Depends on condition, caliber, etc.. Prices can range from 100-700 USD
Not enough information provided for clear answer. Description of type of "pistol" - semi-auto or revolver, markings on firearm, type of action, etc. needed.
50-75 or so
About $100.
"P" prefix indicates 1953
1941
1940's-1950s.
Try Gun Parts Corp
25-175 usd
50-100 USD
Need more information. I Cannot find a reference to an H&R Model 25 bolt action rifle
1930's-40's.