WW2: B-17 Flying Fortress Takes Fire From a Bf 110 | 4k, 60fps, Colorized, Sound Design, AI Enhanced

You see how much damage a B-17 could take? Its a good thing we have real life footage of these encounters.


Well, it’s kinda misleading in a way but you’re correct when it comes to damage against planes in general.

You can only see a single tracer at a time, indicating that only one of the two MG 151/20 is firing.
One seems to jam after the first few seconds of opening fire. (See long video)

The MK 108s where either loaded with early Mine-tracer rounds the later tracerless Mine and Incendiary shells. Since you don’t see any other tracers, the later ammo load was used.
Since the MK 108s carry less than a third of the 20mm ammo, the pilot probably used them firing from range, and didn’t hit because of the greater ballistic drop compared to the 20mm Tracers.

So he his mainly hitting the B-17 with a single MG 151/20.
Since it’s a single tracer with long pause, the ammunition used was probably the later recommended belt of one Mineshell, one Inc-T and one API.

20mm Mineshells are like firecrackers to a huge aircraft like the B-17.
They are fitted with a delay to cause the most damage from the pressure from the blast, but the larger the aircraft, ergo the more space is inside, the lower the damage compared to a smaller target.
Incendiary are the most promising rounds in comparison since they can hit the fuel cells by penetrating through the airframe, while Mineshells require a direct hit.
API can pierce fuel tanks and damage engines but are probably better suited against fighters with armor plates for fuel or pilot.
Causing a fuel fire to an undamaged fuel tank is pretty unlikey unless it’s a huge or very fast incendiary round, so you generally need to land quite a few hits regardless.

I read an account from a Fw 190 pilot taking down a B-24 Liberator using two MG 151/20 (belt: HE, Inc-T, API) and two MG 131 (belt: 2xHEI-T, AP-T)
He spent 360 20mm rounds and ~600 13mm rounds, approaching at 800m from behind and disengaging at 50m.
The B-24 was set on fire and broke in half after a while.

Now the B-24 was supposed to be easier to shoot down compared to the B-17, which I would account to the greater concentration of fuel tanks near the wingroots and fuselage.

Having two pilots and four engines means that creating fuel fires is the best chance to take out a 4-engined bomber unless you hit it with a great amount of explosive at a time.
Regular 20mm HEI would probably fare better than Mineshells, simply because they have a better chance to cause a fire with fragmentation and incendiary hitting fuel tanks.

If you don’t take out the defensive gunners, it would be difficult to take out a bomber with 20mm cannons and even with 30mm Mineshells you would need to land a few hits to make one go down.

Instead all planes just break appart from a few explosive rounds, including 2- and 4-engine bombers.