I show two odd cartridges that seem to be 20 x 139 but the cases are longer.
I think I have an inert Blank and a Chamber gauge ?
The black plastic blank has a steel base and no primer, 4 slits at the nose but the case length is 147mm while measuring as a 20 x 139.
I guess the extra length covers the driving band length and any free-bore before the rifling and would chamber OK but why make it with a longer case ?
The chamber gauge? is all steel and is hollow into the projectile base about 148mm deep. The projectile is darker than the case. 213mm overall length. Measures 20 x 142.
Projectile is stamped: 4179064 7 135000 1 2842
The photo shows an APIT as a guide to show the longer case lengths of the unknown items. All comments on maker and ID are welcome.
I think I have an inert Blank and a Chamber gauge ?
The black plastic blank has a steel base and no primer, 4 slits at the nose but the case length is 147mm while measuring as a 20 x 139.
I guess the extra length covers the driving band length and any free-bore before the rifling and would chamber OK but why make it with a longer case ?
The chamber gauge? is all steel and is hollow into the projectile base about 148mm deep. The projectile is darker than the case. 213mm overall length. Measures 20 x 142.
Projectile is stamped: 4179064 7 135000 1 2842
The photo shows an APIT as a guide to show the longer case lengths of the unknown items. All comments on maker and ID are welcome.
