Taken the spring and magazine follower out of my 2+1 (crimped 7+1) Hatsan MPA tube but can't get the bit from the other end of the tube past the crimp. The Hatsan tube is open ended and has a sort of washer with a hole in the middle that stops the spring from popping out the front of the tube.

I've looked online and think the part number is '403' but I can't see anywhere to buy one.
I'm just being impatient before phoning some dealers on Monday

Cheers
david