gas cylinder lock screw

[RCS]

Not very common to find these days, the early gas cylinder lock screw for the M7 grenade
launcher. The small s is for the stainless steel spring and this was the non returning spring
type - the valve is pushed open it stays open. Duff states these are quite rare. These were
soon replaced by production rifles with the standard poppet valve.4619746198

[Orlando]

I have one but not near as nice condition as yours
Thanks for posting pics

[RCS]

The early M7 grenade launcher when first issued, had one of these early gas cylinder lock screws included in the "kit".

The early gas cylinder lock screw would not accept the M7 launcher. The valve would stay open after firing
a rifle grenade and the user had to fire a ball round to close the value and continue semi auto operation. After production
rifles reached the front with standard poppet gas cylinder lock screws, these early gas cylinder lock screws were no
longer needed and dumped. That is why they are quite rare to find now !