I am quite often asked by Americans: Why are older German shotguns stocked like rifles with pistol grips and cheekpiecces and often with a lot of drop? Why are they overchoked so tight? These questions need a somewhat lengthy explanation.
While the primary use of a British gamegun or waterfowl gun was shooting at “feathers”, flying birds above the gun, the primary German use was for shooting running hares (a relative of the American jackrabbit). As hares rarely fly, shooting at them running is most often downhill. So the guns were stocked accordingly.
Humans usually underestimate horizontal ranges, while we overestimate vertical range. I once measured the distance to a “high flying pheasant” crossing over some trees that I shot overhead to the astonishment of some fellow hunters. The trees were 18 meters high. So that pheasant was not more than 20 m away from the muzzle. On the other hand I often watched hunters opening hostilities on hares 50 m away. My grandfather, like most other hunters of his time, rated a shotgun by the range it would kill a hare. As paper hulls and felt wads were still standard, tight chokes were demanded by German hare hunters. Slugs were for emergency use only. None of these German side by sides was intentionally regulated to shoot Brenneke slugs into an useable group from both barrels.
So in west Germany a 16g side by side, tightly choked and stocked rifle style, was the standard shotgun until the 1960s. Only then, after the decline of hare population due to modern farming, such guns went out of fashion in the west.
In eastern Germany, the GDR it was a different story. As the communists mistrusted all their people, no private ownership of rifled barrels was allowed. So up to 1990 the only guns a highly reliable citizen may have been allowed to buy after years of waiting was a Suhl made double shotgun. As those were used for all hunting, they were often mounted with any available scopes and used with Brenneke type slugs, albeit being not regulated for slug use. Usually only one, the better grouping barrel was sighted in for slug use and used out to 80 m.
The use of buckshot or any other shot load on hoofed game, even the small roe deer, is outlawed in Germany for about hundred years by now, though it took decades until all hunters followed the rule. Brenneke slugs are never used as primary ammo. Just two or three slug loads are carried in a separate pocket on fur and feather hunting, just in case a boar may hide in some bushes. More often slugs are loaded into the left barrel of a drilling to serve at short range, up to 30 m, in case the rifle load fails to stop a boar.