It was made sometime between 1948 and 1952 - need letter code which is usually stamped on left side of receiver or left side of barrel, possibly under the wood/stock. It will be one of the letters: I ('48), J, K, L or M ('52), it may or may not have a serial number - but it will have a date code.
Try e-gunparts.com
40's and 50's
25-100
Your harrington and richardson model 900 was made between the years 1962-1973.
not sure, but I thinks it's a 22 cal...............
No such maker. However, there is a firm called Harrington and Richardson and they did make pistols in 38.
10-100 USD or so
100 USD or so
10-100 usd
25-125 USD or so
10-100 USD or so
50-125 or so