The Sauer M30, also known as the M30 Luftwaffe drilling, Drilling M30 or the Luftwaffedrilling, is a "drilling" combination gun.
The M30 procured by the Luftwaffe was essentially exactly the same as a 1930s commercial hunting model (hence the name), and built to identical standards of fit and finish: as a result, the weapons were extremely expensive. It is thought that Hermann Goering's decision to order the weapon was influenced by his personal fondness for hunting.
It appears to have been primarily procured due to outlandish fears of Luftwaffe crews in North Africa being eaten by lions, since it was issued with soft-pointed rifle bullets it would be a violation of international law to fire at an enemy soldier, and Germany was notoriously against the use of shotguns as weapons of war, having already tried to have them banned after World War 1.
The Drilling was stored in a 32-pound aluminum chest, dismantled into barrel and stock and issued with a sling and cleaning kit, 20 rounds of soft-pointed 9.3x74mmR ammunition, 20 12-gauge slug shells and 25 12-gauge birdshot shells.
Only 2,456 were built over a span of two years. Due to it being relatively rare, the M30 can fetch a rather high price at firearms auctions.
The M30 is a combination gun of the Normaldrilling type, in which a rifle barrel is placed underneath two hammerless shotgun barrels. The weapon is of the break-action type, similar to most double barreled shotguns.
The M30 has two triggers and a sliding selector behind the break-open lever. When the selector is in the forward position, the 100m V-notch rear sight is raised, and the front trigger fires the rifle barrel, while the rear trigger fires the left shotgun barrel. Sliding the selector back retracts the rear sight and makes the front trigger fire the right shotgun barrel. The front trigger is of the "single-set" type popular with European hunting rifles of the time, and so can be pushed forward until it audibly clicks in order to "set" it for a lighter trigger pull. The rear trigger is conventional.
The M30 held a 9.3×74mmR round in the bottom barrel and a 12 gauge shell in the top two. The top left barrel is choked for Brenneke slugs, while the top right barrel is choked for birdshot.