Jag hittar inte mycket om det. Men det jag hittar säger att det fanns ett intresse att göra AA-kanoner med Squeeze bore och HE ammo. Inget definitivt svar.
Här följer ett långt uttdrag från https://weaponsandwarfare.com/2019/08/08/german-wwii-special-artillery-the-taper-bore-guns/
”But if the shortage of tungsten ruled out the taper-bore as an anti-tank weapon, it certainly did not rule it out in other applications, and now the anti-aircraft specialists began to look at the system. In the anti-aircraft business the principal problem was the interval between firing the gun and having the shell arrive in the vicinity of the target; a great deal could happen during that time, and any way of shortening the shell’s time of flight by increasing its velocity was carefully scrutinised. Therefore the taper bore, with its substantial increase in velocity, was a highly attractive idea; the difficulty lay in the design of the projectile. In an anti-tank gun the `payload’ was a lump of inert metal, but in an anti-aircraft gun the payload had to be high explosive. And the dangers which lay in squeezing a high explosive shell were self-evident. With armour-piercing shot the core acted, as it were, as an anvil, while the tapering barrel acted as a hammer, but with an explosive filling the squeezing action had to be carefully controlled so as not to place excessive pressure on the shell body. Two solutions appeared to work satisfactorily. In the first type, the shell was of smaller diameter than the bore and was fitted with two supporting bands of sintered iron, one at the shoulder and one at the base. These were attached in the manner of driving bands, and performed the same function in spinning the shell, but they were malleable so that as the bore reduced they were swaged down and folded back, so that at the muzzle the shell left with two smoothed-down bands which set up minimal air drag. The second method was rather more complex. Three soft studs were fitted at the shoulder of the shell and the base was deeply indented with a semi-circular groove around the body. Into this grove went a malleable skirt with a circular base which fitted into the groove and acted as a sort of flexible ball-joint, turning backwards as the skirt was squeezed down by the reducing bore. At the same time the soft studs at the shoulder were pressed down and deformed until they were mere bumps on the outside of the shell. Again, the result was that as the shell left the muzzle the studs and skirt had been reduced to streamlined excrescenses which set up minimal drag. It was claimed that either of these designs could give a reduction in the time of flight by about 30 per cent, though there appear to be no trials results to back this up. Like so many other developments, the taper-bore anti-aircraft gun was overtaken by events and the war ended before the design could be perfected.”