Rear Wheel Bearings Help

I've just replaced a rear stub axle and I'm have issues with the small outer wheel bearing. As you can see from the picture below it's not slipping all the way on to the stub, I could build it back up and pull it on with the nut but I've not had this problem with any other cars so would just like to ask so I don't make a mess of everything
Cheers Andy

hmm, was it a new pattern part? it should slip on no problem at all