My boss had a SU16 and it was a jam-a-matic. He returned it to the gun store.
Short story-My grandpa would never let me squirrel hunt with a 22 because of the area we hunted so I used what I had, a 12 ga. Three years ago after a long lapse in squirrel hunting I tried a 20 ga. All of the shots I had in a morning were apparently too far for the 2 3/4 " mod choke #6 shells because the squirrels just looked around. Then I backed the next shot up with a lone 3" #6 and dropped the squirrel (basicly made it a 12 ga). This last year I used my Ruger 10-22 with great success, head shots and no bloody meat damage at much longer ranges.
What this taught ME:
For me in a survival situation the 20 ga in particular and maybe the 12 ga. MIGHT not have the range needed to take the only squirrel or rabbit I have seen in a whole day. I mean this is survival, not hunting, if you miss you and your kids go hungry. I think some folks believe that a shotgun increases your chances due to spread of shot. I am not sure that matters unless the targets are moving but the shotgun WILL decrease your range. Same kinda thing with not having a quality scope. How many times have you been hunting and there was no such thing as a close shot at game? Now you are tired, injured, dehydrated and the squirrel is 50 yards away. Are you gonna make that shot with iron sights? I would not be able to reliably.
Make it a scoped .22 for me for survival (with back up iron sights in case the scope got broken of course). But I live in Ohio, the only thing dangerous here is man. I would back it up with a bigger rifle out West.