It’s clear how ineffective rifle caliber bullets are in comparison to even heavy machine gun bullets, since they can only carry little chemical contents.
.303, .50cal and 20mm comparison vs. Bf 109 engine from 200yd
High structural damage but the main spar isn’t compromised other than a large hole in the center of it, as the blast escapes through the thin duralumin skin.
A portion of the skin is blown aways while a large part “balloons”, deforming from the pressure.
30mm Mineshell damage to Spitfire wing (Type B)
HE-T with 72g HTA/Torpex + 3g PETN
Damage of NS-37 and NS-45 shells against a Bf 109 and Ju 87 wing:
NS-37 hole diamater based on wing area destroyed.
Entry: 30cm (Bf 109), 32cm (Ju 87)
Exit: 76.5cm (Bf 109), 67cm (Ju 87)
NS-45 hole diamter:
Entry: μ=58cm (Bf 109), μ=66.8cm (Ju 87)
Exit: μ=87.8cm (Bf 109), μ=91.3cm (Ju 87)
Blast comparison to 30mm Mineshell:
Fragmentation of a N-37 HEFI-T shell:
Out of ~660g recovered fragments from of the ~690g body&fuze, 84.42% (~557.2g) are effective steel fragments with a weight of above 0.5g.
9.4% (62g) with a weight between 0.5-1g
15% (99g) with a weight between 1-2g
11.4% (75g) with a weight between 2-4g
Larger fragments, like parts of the nose fuze and tracer tail assembly, can penetrate armor protecting fuel tanks or pilot.
Comparison of fragment distribution of 30mm HEFI and Mineshell:
Mineshells for the most part only produce fragments with a weight of up to 0.5g, which quickly lose their velocity over a few meters flight path.
Regular explosive rounds produce a much higher number of effective fragments.
Overall nice, tho id rename Various HMG incendary rounds to 15-12,7mm incendary rounds, to be more in line with the 20mm tap as well as technically the 15mm MG 151 is also a Cannon and not a HMG.
Also why no 3,7 cm Brsprgr.18 Vk. L’Spur and 3,7 cm M-Gr.18 L’Spur?
I was actually thinking of adding it next. Would fit nicely between US and SU 37mm shells.
So would be the MG 131 but it’s basially a technicality.
The French 25mm AT cannon would be an AT rifle based on the fact that it’s firing giant jacketed bullets, while 20mm AT rifles would technically be cannons since they fire cannon shells.
So I would simply considered 10-15mm caliber projectiles to be HMG rounds.
Not sure. Maybe a new category with +50mm shells, like the Japanese 57mm.
But there’s not really much interesting to see there.
The 50mm was just to target 4-engined bombers while the 57mm was to target ground targets.
The 45mm shell is technically not much different than the 37mm. It has thicker walls but uses a longer cavity for more explosive.
It’s really only there for some comparison in destructive power.
I rather add some more missing WW2 era ammunition as well as post-war shells, like US 20mm ammo and 30mm ADEN/DEFA shells.
What’s also curious is, that I checked the Ho-203/204 37mm shells and based on the internal volume of the cutaway drawing from US documents, the filler values, that these document give, don’t add up.
Spoiler
From the volume the inner section of the explosive filler would fit around 35g RDX, not considering the explosive around the detonator, and the part that is supposed to be flash powder (Al, Mg, Ba(NO3)²) could fit around 15g.
There’s one Japanese source listing various Army ammunition, including aircrafts hells, stating an explosive filler of 45g.
I only have the edited document from my Ho-401 bug report, so ignore the markings
I thought this might be due to the later shells switching the explosive and incendiary volumes, increasing the weight, due to higher density, but it seems like the filler amount from US documents is simply incorrect.
For a Tracerless 37mm shell to only to contain 30g RDX and 8g Incendiary composition, with a body lenght of ~90mm, doesn’t add up, when the sizes are compard to the Russian NS-37 HEFI-T shell (37g A-IX-2) or the British ~35mm Incendiary-blast-test container, which carried up to 60g Torpex.
There’s another drawing from US documents where the cavity has a diamter of 25mm but shrinks to 22mm at the bottom of the shell. But even then I think it would hold more filler.
Spoiler
Edit: I changed the description for the Ho-203/204 shell:
30g RDX → 45g RDX
8g Flash powder → 12-16g Flash powder
440g weight → 475g
They are more or less true to size.
The 37mm Mineshells walls are thinner at all times and of course the cavity is much longer due to the different tracer design.
I’m pretty sure that 30mm Mineshell without tracer wasn’t fired at 900m/s by the MK 103.
If it was, it probably caused problems that resulted in the velocity be lowered to 860m/s.
Well i did see a ammo drawing for “30mm M-Shell for Mk 101”. Also the He 177 also had Mk 101 and would also have used the M-Gr. Not to mention the Do 217 series.
After some investigation, it turns out that the original values for the Ho-203 HEFI round were correct.
The reference model most likely did not have the right dimensions.
Updated the model and the values:
45g RDX → 30g RDX
12-16g Flash powder → 8g Flash powder
