I think you did pretty good on both guns. I have owned shot and sold quite q few of the 340,s (also the same gun with different model numbers depending what store sold them). Every one of them , all still in use, shoot very good and are accurate. The main thing is making sure you pick up a few magazines before they all disappear. If you change scipes and find you don't have goo eye relief, remember there are two different lengths of the side mount rings. I have had find the longer mount when the guys took their short 4x scopes off and tried to mount a long variable on it. The ring spacing is the difference between the long and short. They may still be available, but doubtful. e-bay would be a good plae to look and I may still have some.
As far as loads, I just remember shooting the 52 gr Hornady BTHP with IMR 4198, and also the 50 gr. HP with 4198 also hornady. They both work good on coyotes and the occsional deer.
If you have any questions, PM or e-mail me and I will maybe be able to help you enjoy a nice old rifle.
Ken
