good thread. racking the slide with one had is a technique i suggest everybody figure out how to master. i am one-armed due to breaking my neck a few years back in a serious auto accident. i cannot rack slides, well, at least not with two hands. hence the reason i purchased a beretta 86 and a .38 revolver for my CCWs. as for hunting rifles, can you say Ultralight....
the way i rack the slide if i'm casually sitting around is by holding the grip against my hip or the hinge in my knee, and handling the slide with my right hand like normal, (four fingers over the top and thumb on the other side). i only hold it deep enough on the grip so the slide has room to be pulled all the way back. i'm trying to figure out other ways to rack the slide as well. the pictured grip up there is pretty impressive, and as stated, it takes a lot of grip strength.
its amazing how you take two hands for granted.