I did a bit more reading about this particular one and apparently only 3 of this type were ever made, the first had the 50mm BK5 cannon and the next two and the more effective Mk214A tht could fire at up to 150rpm
Surprisingly the pilots say that the huge gun made almost no difference to the ME262's handling with a ballast weight in the rear fuselage to counter the mass up front and the recoil was so effectively damped that the only real effect on firing was a loss of yaw stability.
Two B-17's have been claimed as destroyed but this is still under debate (like so much information from this time).
The 262 was done out with a whole stack of different armamnet fits, all sorts of various cannons and rockets were tried, even aerial bombs and bombs with V1 wings being towed behind the fighter...ha ha ha, those crazy Germans!...