I just heard something that I am very curious about and hope someone here can shed some light on the tale. Seems the Germans in WWII used the MG131 13mm gun in a lot of applications including on lot of different A/C and they chose a novel way of allowing the gun to fire through the prop on single engine A/C such as the Bf109.
Whereas ‘everyone’ used a mechanical interrupter to prevent shooting the prop off the plane this application used slip rings to interrupt the current flow to ammunition with electrical primers.
Now, the question: were these guns able to fire standard ammo or did all of them use the electrical primers? I know they were used in other applications such as tanks, etc. as this was one of the very few HMGs they had available so how were they used? And if anyone knows of a more appropriate site to post the question please advise.

I won't speak to the MG131 ammo, but on at least the 75 and 88mm guns they used 2 different (screw in) primers depending on the final application.
IIRC the Tank guns were electric fired while the Flak/Anti-Tank guns used percussion primers.

Probably the best place to ask would be here http://www.quarry.nildram.co.uk/