"Me 262A-1/U4 ("Pulkzerstörer") was fitted with an awesome Mauser MK214 Cannon in its nose. Two Me 262s were modified to carry this weapon - wk/nrs 111899 and 1700083 - and tested at Lager-Lechfeld in March/April 1945"
Quote from:
Me262 Stormbird Rising by Hugh Morgan
Great book, btw