||The SRCM design was the most refined of the Mod.35 grenade series.|
The most significant feature is a fail-safe mechanism which would render the grenade inoperable in the event of a misfire, something the BREDA and OTO lacked.
While at a glance it seems to be simple, the internal mechanism is complex, involving many small parts. It is a rather cumbersome item to assemble and was no doubt an expensive grenade to produce.
|We can see improvement to the safety bar mechanism with a
loose and less binding fit. The brass tape
used in the BREDA is replaced by a fine chain. The safety bar is further
simplified into a thin flat strip.
The method of use for the SRCM is similar to the other Mod.35 types... the pull tab/safety strip is removed, unlocking the safety lever. When thrown, the lever departs, unwinds the chain from the small stud withdrawing the safety bar which arms the grenade.
|SRCM internals as configured prior to impact. |
The firing pin is fixed to the outer casing which is wrapped with a lead sleeve and a coiled fragmentation wire. The explosive capsule, with the primer/detonator, is free to move inside. Once the safety bar has departed, the firing pin is held away from the HE capsule by a creep spring behind a pusher plate with a central hole.
The Allways fuze concept is intended to cause the grenade to detonate no matter how it hits the target.
o Impact Bottom First - Momentum forces the outer casing (with the firing pin) downward into the primer.
o Impact Top First - The HE capsule pushes up to the striker.
o Impact from any side - The assembly is pushed sideways. Top and bottom sloped walls (on both the casing and the grenade body) compress the assembly forcing the firing pin and primer together.
The fail-safe shutter mechanism only permits the primer and firing pin to merge when the grenade hits with sufficient force. There is a range of impact energy by which the grenade functions. Only a hard and sharp impact will detonated the grenade. If too little, the grenade remains armed. A moderate impact, about what might be achieved by dropping, and the shutter safety will cycle to the fail-safe position.
There is no way to determine the state of the safety from the outside.
||Looking up at the shutter. |
It pivots at one end with the other end connected to a long coil spring, under tension. The shutter travels through a stepped slot configuration which gives it a three-stage action. At the last "fail safe" stage, the path leading to the firing pin is covered.
At left is the shutter positioned at the fail-safe point.