Traded my HW 77 for an SS with both a .177 and a .22 barrel, scuba clamp, and a BSquare adjustable riser. Tell the truth, I think I got the better end of the deal :-).
Actually, I have 2 SCUBA tanks, on extended loan from my boss. They haven't been used for years, but one of them was full. They both need to be hydo'd before I can get them filled, but that's only $17 ea., can't complain about that. Closest place to get them filled is about 50 miles away, but I can live with that, too. I still want a pump for those times I just can't get around to getting the tanks filled, or I forget, or I just don't want to haul a tank around. More later.
Dave