The Rheinmetall model 1928 (designed by one Karl Heinemann and made in Switzerland) was one of the rifles tested by US Ordnance in trials that eventually settled on the Garand and Pedersen designs (and ultimately chose the Garand). The Rheinmetall rifle had a pretty interesting combination of features…
It was chambered for the .276 Pedersen cartridge, and used a detachable magazine that mounted horizontally on the left side of the rifle. As you can see in the above photo, it had a toggle-type bolt, but it was neither short recoil like the Luger nor delayed blowback like the Pedersen rifle. Instead, it had a muzzle cup which would capture gas from firing and slide forward (much like the Bang or Liu rifles). This movement was transmitted through a rod under the stock to pull a locking cam out of engagement, thereby unlocking the bolt. Residual pressure in the bore would then throw the bolt backwards to cycle.
Overall weight of the rifle was 4.5kg (9.9 pounds), and magazines were made holding 5, 10, 15, and 25 rounds. It did also have a stripper clip guide on the right side of the action to allow loading by clip. The Ordnance Board like that it was effectively sealed against dirt getting into the action when closed, but disliked several other elements:
- the feed system (they wanted Mannlicher-style clips rather than box mags)
- the sights (it had Mauser-style notch and post sights, and the Board preferred aperture sights)
- the weights (they wanted something under 9 pounds, which the ZH29 proved was possible)
- the number of parts (it had 114)
- the lightweight barrel (which contributed to poor cooling in their opinion)
- unreliable functioning
The Rheinmetall rifle was tested in August of 1929, and removed from further consideration as a result of those problems.
A description of the operation and disassembly of the rifle is available here: