It seems kind of strange that you can only pin someone with surpressive fire from a fully automatic.

I'd imagine semi auto could do it at well. Probably not as well. (-10 to Willpower)

As well as single shots from unknown assailants at (-10) until you spot them.

What do people figure?

Lots of noise and bullets is scary,less noise and bullets is scary but less so.One shot,one dead mate is f****** scary!Someone unfriendly knows what there doing and may hang around for an encore!Its hard to judge how to work that into a rpg so i'd go for your gut instinct.If going for the single shot assailant having a pin test i'd say that it would have to have had some effect.A near miss at the very least and greater effect if a opo is down screaming.

I might house rule it so that groups of people using semi auto or particularly good snipers could cause pinning.

But for the most part I agree. In real life that is the entire point and utility of full auto fire, pinning. light and heavy machine guns really are meant to make people keep their heads down more than hit people.

And full auto fire is just a lot more likely to psychologically FORCE someone to pin, even though any weapon could make them choose to duck and cover.

Pinning also implies inability to move. With semi-auto fire the target is likely to be able to time their escape, whereas full auto really makes escape impossible.

All in all, I would leave it as is except for in special circumstances.

Rip adds a good point that pinning is the thought that you cant move.So i'd go with his idea.To add to it though rather than have a pinning test because of a very good sniper role play it to the max.With a sniper you can move,you can get up and dance naked.The problem is that is what he's inviting you to do.He's leaving you lots of options.Has he gone after his shot and its safe,is he waiting for you to move etc,etc.Its not the impossibility of movement which needs a WP test to beat.Its the knowledge that he may just be teeing you up for a good night vienna head shot.Thats why its up to the pc to move.A good GM could really play this one outWhich certainly leaves me out of the equation!!!