20 x 138 Rheinmetall (Solothurn) Question


The attached picture shows an AP projectile which has come out of an unheadstamped brass 20 x 138 mm case. There are no stampings or markings on the body of the shot/shell? The rear of the projectile beneath the driving band appears to be screw threaded and in the inset you can see two keyways cut out of the base. I have tried to gently unscrew the base but cannot do so. The item needs to be certified as Free From Explosive. Does anyone know the construction of the projectile and what sits beneath the base? In addition what nationality is it?

Thanks in advance.



Some of these plugs can be left-hand threaded. This is to prevent the plug from unscrewing itself if fired in a gun with right-hand rifling. Try gently turning it the opposite way if you haven’t already done so.


Buster, could you show us the case head and tell what kind of flash channels you can see inside the case?


Falcon - Yes I did try turning the base both ways. EOD another pic attached, internally there are two fireholes. I realize that it is a fired case and that there is no guarantee that the progectile and the case match. However that is how I found it.