There were dozens of different top break models made by Harrington & Richardson. Your best bet will be a search engine, such as Google. Select IMAGES, then Harrington & Richardson. The link below takes you to ONE such image- a nickel plated, top break 38 S&W hammerless revolver by H&R.
60 or so
50-1000 usd
Pi Squared
50-1000 usd
50-500 USD or more depending on EXACTLY what you have.
$ 150
What model?
50-275 or so
50-500 usd
100-10000 USD depending on EXACTLY what you have.
The value of a High Standard Sentinel Deluxe Model R-107 nickel-plated revolver can vary depending on its condition, rarity, and current market demand. Generally, they can range from $300 to $600 in good condition.