The .22 BSA Wolverine (rebranded JSB Exacts) went completely through the first 2 and pierced one side of the 3rd. I don't have doubt that .22 cal has the penetration I need for hunting (when shot from my RWS 48 anyways)!
I think I put over 700 shots through this gun now. Hope I get at least 4000 more (hope some of those 10k claims from others aren't BS)!
I have shot many thousands of shots through most of my RWS guns. I own 4 RWS models and I can say for sure that the model 350 has had at least 15k shots. I recently put the 3rd spring/seal in it and it is shooting extremely well. These guns should shoot for ever if you maintain them well. 4K shots is nothing. The first spring should handle that easily. Good luck!
I think you will really see the accuracy potential if you put a scope on there. The factory iron sight leaves a lot to be desired, especially if you eyes have a few miles on them.....If you do go with a scope, read up on scope mounting issues with Diana's to save yourself a few headaches (droop, recoil rated scopes, etc.)
I like iron sights! The rear leaf is trash but I can change that. I saw a rear sight for the Diana pistols on Pyramid Air's website. It has a rotating leaf with 4 selectable notches and I wonder if it will work with my 48. I always heard that 48's came with a rotating leaf but I haven't found that to be true with mine.
48 is correct in advising you to get a scope. I shot my 54 without for awhile and when I put a scope and mount on, WOW! Head shots at 40 to 50 yards on morning doves. There are some issues with mounts and scopes so read blogs from this website and you'll be much better shot.