MX5 is the gun series, in this case higher end MP5s.
BT5 is the trades on the receiver, from the real steel company Brügger & Thomet. They also sell their MP5s without trades and they call them plain MX5 for the high end and sportline MP5 for the low end.
Keep quiet. Sound travels faster than BBs.
Québec province's master age verification representative.