You have a 2nd Model AUTO EJECTING revolver 3rd Variation. Just for fun - here's a couple pics of 3rd Mod, 1st Var. As to shooting some one else's handloads - from personal experience - I discourage that activity UNLESS you know the guy very well and he has demonstrated some competence in reloading - UNKNOWNs often result in KABOOMS and damage and injury - just my OPINION. BEFORE shooting it, I strongly suggest that you have it checked by a competent gunsmith for safety and function. The gun was made to handle smokeless powder - how it was treated over the past 100+ years is an unkown. The s/n will be found in two other places: under the left grip panel on the cross strut of the grip frame and the REAL serial number will be found under the top strap - you have to remove the cylinder to see it - and may include a letter prefix which would pin the year of manuf. A serial number in that range puts it into the later part of the variation production probably '08 or so. It is an example of the first H&R top breaks made to handle smokeless/Nitro powder loads. Your friends gun is a 3rd Model 1st Variation and made between 19 (circa).