Are you sure it's single action only? You might have something rather rare. I've read that H&R made some sa only 999's. I've never seen one myself. Great little guns.. Glad I got mine before prices went crazy on them. I see guys on GB asking up to $700 recently. People must be losing their minds I tell ya!A few years ago I bought this H&R 999 from a friend that
bought a small collection. The bore is excellent and action
is tight, it is single action only with a very nice trigger. The
height of the front sight is adjustable with a screw. I believe
this revolver is from the mid to late 1930's and found it in a
1939 catalog showing five different types of grips you could
install. The pin on the left side will remove the cylinder when
the action is open. I have shot 22 long rifle at the regular range,
it also likes 22 longs when you can find them. Recently I found
a box of CCI 22short target and tried this out at 15 feet.
Edit: I see yours is a bit different than mine. Like I said, never seen one sa only.