Ah, ok...I've been misunderstood I meant this for a BW, for a FW I ruled it out and built a Co2 powered one. A 350kg electromagnet would have been too heavy and bulky.
But for a BW it might work.
This is a 20kg magnet... weighs only 46 gr
http://www.kjmagnetics.com/proddetai...CB-N52&cat=168