Have a Henschel Hs-129.
It was available with a really, really, big gun.
It’s all Russian to me, but I’m told that it was a 75mm cannon with 12 shells used for attacking tanks. The whole assembly weighed about 1200 kg which did nothing for the performance of an already slow plane. Theoretically it could have destroyed any tank in the world at the time, in practice there were too few made to be of any use and in any case it turned out much less effective than its specs would suggest.
The cannon was made by Rheinmetall who are still around and still in the gun business.
Henschel returned to the railway locomotive business after the war and having passed through several names and at least one law suit (with Daimler on the receiving end) are now owned by Bombardier and trade as Bombardier Transportation..