I loaded some up possible deer loads.
Fired it at a 1/2 gallon juice jug filled with water in front of 2 more milk jugs full of water. The sig 124gr bullet jacket separated, fragmented and the core fragmented. I recovered the core just barely sticking in the cardboard bullet catch. Found fragments and jacket bits in the milk jugs. Recovered several peices weighing a total of 111gr, the core weighed 77gr. There were frag holes in the back the first gallon milk jug the bullet encountered.
Not posting the load as it exceeds the max load a bit, the load is compreseed and its swapped up to a magnum primer, plus the coal length for that bullets ogive won't fit most guns any ways as the sten has good bit of free bore. But no scarry pressure signs. Velocity was a little over 1,500fps.
Holey crap it exploded the juice jug and the first milk jug like a rifle.
Yeah should probably switch to a 147gr.
Go with standard primer and a 9mm major load of AA7 or HS-6, probably load it in shellshock cases.