B&T owner Karl Brügger is a big fan of 9mm PCCs and SMGs, and decided that his company ought to offer an alternative to the MP5 and this was the Advanced Police Carbine (APC). In order to compete effectively, it needed to be simple to manufacture, since manufacturing costs in Switzerland are exorbitant compared to virtually everywhere else. So the design is based on an aluminum extrusion for the receiver, with a polymer grip and fire control housing. The APC-9 is hammer-fired from a closed bolt (like the MP5) and to keep the rate of fire down to something reasonable, a hydraulic buffer is fitted to the stock.
The APC-9 is available in a huge number of variations in barrel length, color, and magazine compatibility, as B&T prides itself on accommodating customized requests from clients (unlike the MP5…). It has been adopted by a large swath of police agencies in Switzerland, Europe at large, and also in the United States. It is not the cheapest option out there by any means but it is reliable, simple, and backed by excellent customer service.
“(…)offer an alternative to(…)MP5(…)”
My cursory search revealed only folding-stocking APC, whilst MP5 is also known to exist in fixed-stock version. Was similar variant of APC developed or not, if latter why?