If you consult a book or video on disassembly of H&R revolvers, make sure it has re-assembly instructions, not just "reassemble in reverse." Reassembling H&R's requires use of a "slave pin" (the politically correct now call it a "helper pin") and some experience, other wise you end up with a gun no one wants to put back together.
Jim
PS and FWIW, H&R changed their hand and hand spring system several times, so if you order a hand and spring from a parts house, make sure you provide the model number and serial number and, if possible, a drawing or picture of the old part.
JK