Hi Tom. For us in the UK, the Zib MG42 was the only legal way really. It would have been cheaper to modify a deactivated one but that's against the law.
The real steel parts I used were rear sight, cocking handle, front sight, cone retainer and barrel change door.
Not sure about the total cost but for the gun and parts but, it was under £500. Then add on the cost of the drum magazine and internals, as well as the gearbox, barrel, hop, outer barrel, etc. Some may say that's a lot but, I disagree. I think it was totally worth it to produce 2 working, authentic (and f**king heavy!) airsoft MG42's.
When I want your opinion - I'll tell you what it is!
Alright 
thanks for the answer, i think i'll build one. Cause in Denmark a mg42 deactivated would sell for about 1600 gbp (ca 14000 dkkr) not to talk about it would be illegal to build it into an airsoft ... So i think i'll build one out of the Zib version...
