I had one, or rather I had an M40-A1 and a 357 SIG conversion barrel.
357 SIG is a blast, literally. I would not want to fire one indoors without hearing protection.
If I hadn't been jobless for a while I'd never have sold it.
They are harder to come by, but they are still in production, we just don't get many of 'em across The Pond. <shrug>
LEO's and Spec Forces are well aware of their superb performance envelopes with a variety of bullets, from 85 gr to 158 gr JHP's, taylor-made.
We hadda thread that alerted Club Members of their availability, but I guess that hasn't been used for a while now. I keep checkin' up on Gunbroker.com and haven't seen many surface of late...not at prices I could afford.
I think maybe there is a close following and they are bought whenever thay become available.
Eventually they will surface again in greater quantities, but for now be vigilant.