Original SA 1943 annealed receivers

[RCS]

How were annealed receivers related to grenade launching ?

[GPlourde]

My 1746xxx is annealed and 828xxx is not. HTH Gregg

[Garandrew]

Receivers were cracking, from experience in North Africa launching rifle grenades, it was found that softening the steel receiver heel, and sometimes legs, by lead pot annealing, prevented the cracking, till the steel mixture was changed.
I think the problem was solved by 1944.

[RCS]

valve screw assembly B147851 isued with the M7 launcher in 1943, replaced by the poppet assembly in Jan 1944.

The early valve screw vented the gas when launching grenades or ground signals and also prevented the M1 from semi auto operation with ball cartridges (as the gas system was vented by the M7) until the M7 was
removed.

My question, how is the bolt (when launching a grenade or ground signal) making contact with the receiver heel when the gas system is being vented
by the valve screw and M7 ?

[Dave Waits]

valve screw assembly B147851 isued with the M7 launcher in 1943, replaced by the poppet assembly in Jan 1944.

The early valve screw vented the gas when launching grenades or ground signals and also prevented the M1 from semi auto operation with ball cartridges (as the gas system was vented by the M7) until the M7 was
removed.

My question, how is the bolt (when launching a grenade or ground signal) making contact with the receiver heel when the gas system is being vented
by the valve screw and M7 ?

It isn't, the annealed receivers were done before the advent of the Poppet-Valvescrew as a tempotary fix. The special round used created too much bolt-speed and the bolts were slamming against the rear of the receiver. The early screw was solid. Unless I misunderstood your question.

[latigo 1]

RCS is right. The grenade launcher was purposely designed so it could not be used with the early unvented gas screw. The pin on the launcher was too big to fit in the hole of the single slot screw. A vented screw was sent with each grenade launcher and any rifle that did not have the new vented screw could not be used for grenade launching.

[SUB VET II]

Have receiver 1458xxx. Probably Feb. Mar. 43. It does have a 51 H@R barrel.
Have restocked with a Boyd. Rifle is very accurate.

[RCS]

I have a few early rifles with the solid gas cylinder lock screw, I have not been able to install the M7 or variations M7A1 etc launcher on a rifle with an original solid lock screw. Also as a note, the M5 bayonet will not fit a rifle
with the solid lock screw either.

There have been fake or repro solid lock screws available for sale and these
screws have a larger diameter center hole which will fit the M5 bayonet

[Bill Ricca]

Annealed receivers due to Grenade Launching is the same myth as why they altered op rods.

Go here for a complete explanation:


http://www.billricca.com/myths.htm#anneal

[Dave Waits]

Thanks bill, always willing to learn.