Let me pile and say that $130 for a High Standard Sentinel Deluxe is an exceptional price in 2025. They used to be widely available at low prices but like everything else gun related, skyrocketed in cost after COVID.
Sentinels often shoot a bit high. I found that my R-101 shoots to point of aim with lighter, faster ammunition such as CCI Stingers or Federal Punch. But try several different kinds of .22s to see what your gun likes.
The DA pull is stout but with some practice is usable, especially if you debur the trigger serrations.
They can be tricky to reassemble so taking it down beyond removing the cylinder is not recommended. It's a good idea to remove the grip, cock the hammer, then hose the action out with something like Rem Oil, followed up with a blast of compressed air (canned air sold for dusting computers works well if you don't have a compressor).
I am a big fan of these revolvers.
View attachment 1259622