How so?? Take a picture is this the plastic one?
IF so you have options of your arms. The staff and a gun or something.

 

Yes, it's the plastic one.

Warhammer 40,000 - Chaos Space Marines

If you look at that link, the sorcerer staff has a hand, but not an arm.

 

I know there should be an arm with nothing on end, it should fit onto that.

 

There should be one, but it's not there, unless I'm just plain blind.

 

Well, it looks like it shoulbd beside the books and sprite thing, i cant remember exactly but that is the only spare sprue piece on Gws picture.

 

Maybe they accidentally left it out when they mass produced them

 

No, they didnt as I have one. Maybe take it back to GW and complain or ring GW and say you were missing it.

 

if you have a look at the sprue on the GW site, it is actually had a couple of Sorceror specific parts clipped off already, one of them is the arm for the staff (but I can't remember which one it is). The missing pieces are next to the trophy racks and next to the familiar (in the very corner) just in case you missed them.

 

Yeah, if you read the replies I realised that but thanks for confirming it for me, I wasn't quite sure.

 

Hmmmm, I'm blind and possibly retarded. Found the arm. Don't know how I missed it last night

 

Haha, good