How I understand it from chatting with Tony (NE450No2) and Fred (CFA) at the DRSS hunt this past April, Tony had the Holland from Fred and was giving it a once over and test firing it with standard reloaded ammo (NOT hot loads).

The barrel blew after only a few rounds went through the pipe.

This is how I remember the conversation about the rifle, but if CFA or NE450No2 remembers it differently, take their word as law.