- Yes
- No
I would like to suggest the posibility of the Do 17 Z-7 to change out the barrle of the 20mm Mg 151/20 to the 15mm barrle via a modification like allready available to later Bf 109s.
It was intended as both a Night fighter and Ground Striker, in which the 15mm Version would be more effective, along the Pilots could choose to change barrle and ammo.
Historically speaking the 15mm Mg 151/15 started development in the 1930 as was inteded to be the main stay of high performance Motorkanone against Air and ground targets alike, envisioned with the same successes as the French with 20mm Hispano 404 allready archived. Mauser was tasked to develop a 15mm gun with a similar strength to the 20mm Hispano 404, but lighter, faster fireing and smaller to fit into the smaller nose of the Bf 109 and other planes. While generally effective, it was found that while good against ground targets, with very good ballistics (960m/s) it was however felt that it lacked performance against air targets, especially bombers, as in general planes started switching over to metal construction instead of wood with cloth.
As such the shells of the previously adapted 20mm Mg FF (and /M) envisioned as a stop gap, were taken over and put into shortened to 82mm Mg 151 casings, to retain the overall length and dimensions, changing out the barrle to a shorter 20mm barrle (to keep the weight a bit more down as it still went form 37kg to 42kg) to archive greater destructive potential against (unarmored) ground targets and airtragets.
It was then developed to be able to simply exchange the barrle and ammo to change between the ammo as both were continued to be uses as well as came with different stregthes.
Pictures showing both armarments:(Click to show)
Here first a Do 17 Z-7 with the visibly longer 15mm barrle
Compared to the shorter 20mm
As also Munition für Fliegerbordwaffen Teil 10 sayes:(Click to show)
(1) Important for choosing the ammo types is:
a) Archiving the greatest affect,
b) most logical ammo usage, accordingly to supply.
(2) The formation leader has to archiv, with knowlege of each ammo types, to get the greatest affect when belting the ammo. (…)
And based on the ammo as well, the Mg 151/20 is better against soft, light armored and air targets, while the Mg 151/15 duo to its specifically against tanks designed H-Pzgr is better against Tanks and Medium to even Heavy targets, while also retaining duo to other ammo kinds good affect against Air targets.
Here some more info about the 15mm H-Pzgr. o.Zerl
Its an 15mm Apcr round with driving band, light alloy (with some incendary propertys) carrier with tungsten core. (And is in game a bit wrong, Ap-I(c) → Apcr and velocity 1020 → 1050m/s)
H-Pzgr. o.Zerl. (HVAP) 0,052 1050m/s 39g core 9,5mm 51mm/10m
(Different version is 0,0545kg with 1040m/s, however aparently all encountered were 52g (as captured by the USA, Britain and USSR))
Source:
L.Dv.4000/10
D.(Luft) T.6151 Mg 151 und Mg 151/20 Waffen Handbuch
Do 17 Z-7 Manual
Kauz Night Figthers
Private gallery