There were two experimental samples, the He 319 and He 419 V1, with a MG 15 as "Attrape" , was later equipped with a stronger mount.
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The test squadron was stationed at Rechlin.
Nachtjagdgeschwader 200
The squadron was often used for training and test flights, such as for the Y-process at Rechlin.
http://www.lexikon-der-wehrmacht.de/...Gliederung.htm
I doubt it but myself.
None of the 155 series machines of the Heinkel 219 was armed with an ancient MG 15.
This was introduced in 1942 only to the airfield defense, the Army Luftwaffendivsionen or in old aircraft types.
The Heinkel 219 had an armament between 4 MG 151 and MK 103 or MK 108 (Maschinenkanonen).