13mm MG 131 in ground role?

[Tony Williams]

I have seen photos of the Luftwaffe's 13mm MG 131 being used in the ground role, with what looks like a bipod mounting.

This puzzles me because although some prototypes were percussion-primed (and the Japanese adopted that version), the Luftwaffe MG 131 were all electric-primed. So a power source was needed to fire the gun; a nearby generator or, at least, a battery.

Does anyone know how this was done?

Tony Williams: Military gun and ammunition website and discussion forum

[Ardee]

Can you post the photos?

I assume you are not referring to guns mounted non halftracks....

[Tony Williams]

This is one:

[PPoS]

The answer is that the "aircraft version" of the weapon fired at the original rate of fire of 930/min. Electrically primed ammunition was fired to sustain a high RoF (abled the weapon to be shot through the propeller) but the weapon was modified to a RoF of 900/min in ground role, so it wouldn't need this power source.

[Tony Williams]

Sorry, but that doesn't work.

Electrical priming was selected for the MG 131 in order to help with synchronisation, all right, but that was because the synch system just sent an electrical current to the primer, which instantly heated up and fired the propellant. This was quicker than the usual system (as used by the MG 17) in which the electrical signal from the synch system activated a solenoid which released the sear, allowing the firing pin to run forward and hit the primer.

The MG 131 did not have a firing pin, just a contact to allow the current to flow to the primer. The primer could only be fired by an electrical current, not by a blow from a firing pin.

So the only way that you could use an MG 131 with no electrical current would be to:

1. Convert the gun to firing percussion ammunition, which would involve removing the electrical contact and installing a firing pin wtih the necessary sear and trigger.

2. Set up a production line to produce ammunition with percussion rather than electrical primers.

3. Set up a supply chain to get the special percussion-primed ammo to the modified guns.

I would be happy to see evidence of any of these things, but AFAIK there is no evidence that any of them was done.

So, how did the MG 131 work in the ground role?

Tony Williams: Military gun and ammunition website and discussion forum

[Tero T]

I am not a firearms expert but I thought I would throw this into the discussion. This is not regarding the 131 but the 151 and post war. 1950 when the Finns were re-assessing their military and what threats were posed by the Soviet Union. One of those threats was the coming age of helicopters. Thus it was important to beef up airfield areas with 20mm AA. The Finns has many MG151's that were stripped from ME-109's . They made a balanced twin 20mm AA without any hydraulics ,purely manpower operated. It was interesting that they still used the mounts off of the 109's as well. The picture is from a new book on AA out of Finland enititled " Anti Aircraft artillery of Independant Finland 1917-2000" by Raimo Vehviläinen , Ahti Lappi and Markku Palokangas. Regards Tero T

[Tony Williams]

The Mauser MG 151 was available in both electric and percussion primed versions. As far as I know, the only service use of the electric-primed ones was by the Fw 190. The Bf 109 certainly used the percussion-primed type, so there would have been no problem in using them in the ground role.

Incidentally, the MG 151/20 is still made today - as the Vektor GA-1, by Denel of South Africa.

Tony Williams: Military gun and ammunition website and discussion forum

[PPoS]

Well I guess that when they coverted the MG-131 to groundrole they probably did it as you're first option:

1. Convert the gun to firing percussion ammunition, which would involve removing the electrical contact and installing a firing pin wtih the necessary sear and trigger.

[Tony Williams]

Well I guess that when they coverted the MG-131 to groundrole they probably did it as you're first option:

1. Convert the gun to firing percussion ammunition, which would involve removing the electrical contact and installing a firing pin wtih the necessary sear and trigger.

Those weren't options - you would have to do all three for it to work. The electrical primers of the standard MG 131 ammo would not be ignited by being struck by a firing pin.

Tony Williams: Military gun and ammunition website and discussion forum

[tommy303]

I suspect, from the foto, the MG131 in question might have been a captured piece from a downed German plane and modified by the Russians for testing the weapon's ballistical performance. The bipod mount clamps to the usual attachment point for the free swing or turret mount of the aircraft. I suppose it would be possible to use in a ground role, but I would very much hate to have to carry it and battery pack, not to mention having to fire it from a bipod and braced on my shoulder. It would be much better used from a vehicle using the vehicle's electrical system.

[PPoS]

Well I guess that when they coverted the MG-131 to groundrole they probably did it as you're first option:

1. Convert the gun to firing percussion ammunition, which would involve removing the electrical contact and installing a firing pin wtih the necessary sear and trigger.

Those weren't options - you would have to do all three for it to work. The electrical primers of the standard MG 131 ammo would not be ignited by being struck by a firing pin.

Tony Williams: Military gun and ammunition website and discussion forum

Ah ok I understand. I'm no expert on this at all, but if it's to any help the only thing I know is that the A/C version had a RoF of 930rds/min and the "Erdeinsatz" had a RoF of 900rds/min. I supposed this had something with the conversion to do.

BTW, does anyone know how much power would be needed to fire this weapon ?

[Meczyk]

In another thread on this forum there was a different picture
http://forum.axishistory.com/viewtopic. ... &start=900

[kfbr392]

Luftwaffe MG 131 were all electric-primed. So a power source was needed to fire the gun; a nearby generator or, at least, a battery.

Does anyone know how this was done?

There were two different aircraft versions of the MG 131:
1) for rigid mounting: electric firing, pneumatic charging; no pistol grip
2) for flexible mounting: with pistol grip, firing pin, charging handle

I suspect the latter will have been the one pressed into the ground role.

Picture from Wollert&Lidschun book:

[Tony Williams]

Some experiments were carried out with a percussion-primed version of the MG 131 and this was adopted by the Japanese Navy as a flexibly-mounted aircraft gun. However, this was never adopted by the Luftwaffe.

Both the fixed and flexibly-mounted versions of the Luftwaffe MG 131 were electric primed.

My reason for saying this is that I belong to the European cartridge research association, and collect military ammunition. It is well known among collectors that all of the Luftwaffe MG 131 ammunition was electric primed, and easy to check as the electric primers look different from percussion ones.

[kfbr392]

Good day Mr. Williams, glad you noticed my thread-necromancy.

That is interesting.
There is no question you are an expert with hands on experience. And I value your writings. I can only speak based on the reading I did. In the Lidschun book, it reads as if the flexible guns may not have been electro-pneumatic, but it is not 100% clearly stated by the author...