Bf 109K Armament

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

Emil Kurfurst

Apr 15, 2004

I am looking for information concerning the 109K carrying the Two 15mm MG 151's in the cowl instead of the 13mm guns.

I am looking for any reliable resources on this. Messerschmitt documents, Wrknmr's and so on.


All I know that Bf 109K-4 use armaments 1 x 20mm on fuselage centreline plus 2 x 20mm in fuse lage, 2 x 20 mm in gondolas under wings.
no it didnt.... it never used 20 mike-mikes (vietnam slang for 20mm vulcan, i use it for all 20mm guns) ,at least not the K-4.....
it had two 13mm guns and a 30mm cannon, BF-109s NEVER carried guns on the centerline as well occasionally bombs but usually a fuel tank! the K-4 could carry two more 30mm guns under the wings if wanted but usually just Fuselage armament so that they could dogfight with less drag.
Well, You know more about Bf 109K-4 than I do, but rarely I heard that US got K-4 after German surrender and test K-4 against all Propeller and Jet fighter, but that just probably don't exist
The MG-151 is a 20 mm cannon. The MK-108 is a 30 mm cannon and last but not least is the MK-114 which is a 50 mm cannon. The MK-114 was used for bomber busting. The MK-108 30 mm cannon was on the ME-262 and other german fighters. But its cyclic rate of fire was very slow so a high speed fighter only had a small window of shooting time because of the closing speed between the fighter and it's target was so short. If the German's cannon could have fired faster more bullets would have found their target. Thats the reason that General Electric developed the Vulcan (6 barrel ,hydraulicaly actuated and electric primed 20 mm shells) 20 mm cannon for the new generation of fighters because of their speed. Firing 6000 rounds per minute puts a lot of 20 mm bullets in the air when firing. I think that the Germans also used electrical primed shells in some of their cannons in WW2 . I know that the 20 mm Vulcan cannon used 208 volts to ignite the primers in the 20 mm shells fired in them.
I was gone for the weekend, sorry about the lack of replies on my part.

I know the K-4's carried the 13mm MG 131 in the cowl. They also carried the mk108 30mm cannon in the spinner.

They never carried 20mm's in the cowl. I think where Rafe got this idea is rooted in a typical printed error.

The 15mm guns I'm looking for are:

Waffenfabrik Mauser AG Mg 151/15 which are 15mm.

The one Rafe is reffering to I think is the:

Waffenfabrik Mauser AG Mg 151/20 which are 20mm.

I'm looking for resources to verify that it carried the 15mm. There are numerous ones on the 13mm being carried.
According to the book Messerscmitt Bf-109 by Robert Grinsell, the prototype K-0 and at least some of the production K-2 and K-4 variants carried two of the 15mm versions of the MG-151.
LG but the K-O was never operational. As said the standard of two 13mm's and 1 Mk 108 though the longer barreled MK 103 was considered.


E ~
Erich even the prototypes or the single K2 were fitted with MG131s, there were simply no space to fit such a large weapon as the MG151, 15mm or 20mm since there were nearly the same length (just the barrel and a few internal parts were differents).
The MG151 was fitted as a cowl gun on larger aircraft, the Do 335 for instance, as there were enough space. Moreover it was more desirable than MG131 in that case since the ballistics of the 15mm MG151 were quite close to those of the MK103 used on thsi aircraft.

The engine mounted variant of the MK103, the MK103M was still in development when war ended as there were quite a bunch of modifications to introduce over the original design.

As an engine mounted weapon the K-4 relied on the MK108, which did not have excellent ballistics but a high RoF, which is desirable on a fighter. The K-4 could as well be equipped with under wing gondolas but this was rarely if ever carried as they had a detrimental effects on speed and handling and a very different ballistic compared to MK108.
The MG151/20 gondolas had their use when the 109 were still relying on a 20mm engine mounted cannon but with the introduction of the /U4 aircraft equipped with MK108 and the K-4 it was not more needed. Indeed the firepower was sufficient to down a bomber much more easily than with gondolas and without suffering from maneuvrability/performances losses.
The MK108 gondolas were tested on a few aircraft but were not usued operationaly as they had a very detrimental effect on perf and had only 35 30mm shots each. But the next in line in the Kurfurst family was planned as a three MK108 equipped aircraft with one being mounted behind the engine like the K-4, and two in the wings in seme recessed gondolas which were much more aerodynamic.

Oliver I think your answer was not directed to me but someone else. As I said 13mm's were supplied not the 15mm's that another had said. The gondaola 2cm was considered for night ground attack work in I./NJG 11 fitted to the unit ............ agasint Allied and Soviet MT.

good to see you here.

E ~
Yup sorry erich ;) still a bit tired from yesterday...

AT with the MG151 could have worked out using the PzBr Granaten, but at that time of war larger caliber weapons had to be preferred (30mm and up) due to the increase in armor thickness. Even in shallow dive attack the 20mm would have had a hard time destroying a tank, but a lucky hit was always possible.
Does your source explicitely mentions K-4 or just 109s as anti-tank aircraft with 20mm Gondolas ?
I do know of K's being operated in I./NJG 1 but not in the other two gruppen of NJG 11. 2cm gondolas were used in the late war ground attack role. Now I am assuming without digging through the archival materials but I could be wrong and they may have been G-14's or G-10's.

U had too much fun on your birthday O ! :)

I've seen enough sources mention 15mm cowl weapons, specifically the Mauser 151/15mm, to believe that the K-4 was equipped with them.
I'm reversing my position. After reading numerous references, mostly on the internet, I am now convinced that the production version of the K4 had the normal 13 mm cowl machine guns which were also carried by the G6 and G14. The 15mm guns proved to be too big in the trials of the K4.

Users who are viewing this thread