5-150 USD depenidng on specifics.
50-125 or so
Best left to a gunsmith
Try e-gunparts.com, gun shows, internet, want ads.
Excellent condition: $325 fair condition: $150 Add $25 if you have both the .22lr and .22wmrf cylinders.
HR is Harrington & Richardson. They first made guns in the US in 1871. The company changed structure several times, and is now part of Remington.
50-150 USD or so depending on condition
This Model 676 was equipped from the factory with both a .22lr cylinder and a .22 wmrf cylinder - depending upon condition and barrel length (12" barrel commands a 20% premium) value will range from Excellent - $275 down to Fair - $75.
50-150 in poor to average condition. In Excellent condtion, with box and both .22lr and .22 magnum cylinders this model has sold in the $300 range.
No such model number in the S&W line
I bought mine in 1977.
50-100 USD