Marlin 1894 10mm/40 S&W Short Stroke Carbine (10/40SS)
The RPP 10/40SS is a unique rifle, so much so that it is the first of its kind. It represents a number of extraordinary developments in the Marlin lever-action platform, if not repeating rifles as a whole class. To our knowledge, there is nothing else like it.
To begin with, this rifle could not have been built without first developing our exceptional
M/94 Extractor Claw, which itself was the product of months and months of intensive R&D work. Unlike, say, the .38spl and .357 mag, which headspace on their rims, the 10mm auto and .40 S&W headspace on their case mouths. So while the longer 10mm headspaces normally in this rifle, the .40 S&W round is held against the bolt face by the extractor alone.
Firing the .40 S&W in a 10mm chamber requires that two conditions are met: 1) the action must be set up for controlled round feed--ie, the extractor must take control of the case rim immediately during carrier lift--a matter of split second timing when two disparate cartridges are involved; and 2) the extractor must hold onto the case rim, and remain undamaged, under repeated duress, as the firing pin smacks the primer, driving the cartridge forward against the extractor. Only RPP's M/94 Extractor is tough enough to handle this punishment.
A host of modifications and careful tuning are necessary to achieve the foregoing conditions. It is important to note, that despite our best efforts (to date) time and gravity may still affect the feeding of .40s in the Marlin. The 10mm cartridge, being long enough to span the carrier bed, will run as reliably as any firearm can be made to run, but while the .40 will run reliably under most conditions, there are circumstances under which it may malfunction.
For this reason, the .40 S&W should be considered a bonus round, good for cheap plinking and small game hunting, but it should not be relied upon for critical duty.