Been offered a Mauser 4000 made by Heym for a bargain price

It was originally a 223, but has been rebarrelled to 17 Rem, by Bill Hamberly Clark (A top Australian gunsmith at the time) about 25 years ago
Only fired a few boxes of factory ammo, since the rebarrel, and has been a safe queen for the last 24 odd years

I can't recall ever seeing a Mauser 4000, so googled it, and found a bit of info, and a few pictures, but nothing much about the action design, or specifications..

Apparently its the same as a Heym SR40, with a different stock..

Should be a quality thing as Heym don't make crap...

So anyone got one or had one or can tell me anything about them?

Thanks
spinna