Need help with semi auto L4A4

[WallyG.]

Greetings: It's been a while... here are some observations from my experiences to date with HA manufactured Semi Auto Brens.

1. The gas cylinder should not be wobbly in the receiver body... it should be rock solid. Why? Hard to diagnose from a distance - both physically and time since manufacture.
2. HA guns typically have the gas port in the barrel enlarged - size may vary depending on the gun.
3. Typically, only one gas port setting on the gas nut is enlarged from the standard size and that is one to "match" the enlarged barrel port - providing more gas to power the SA internals that weigh much more than the standard internals and also to overcome the introduction of the striker spring to the recoil system. Note: HA guns typically have the "as built" recoil buffer assembly removed to accommodate the striker spring length and the striker - which also acts as a recoil buffer but one of a simpler design and being physically present between the bolt and the rear of the receiver.

Different gas settings in an original Bren (once sufficient gas is provided to successfully cycle the action/internals) that provide more gas should still function but just beat your shoulder and the gun up from the excessive recoil impulse. I have read opinions that gunners used to run their guns over gassed to eliminate the possibility of a short stroke failure during combat. Too much gas should not cause feeding issues. The original gun as designed just absorbed the heavier rearward impulse force and the recoil spring returned the bolt in the cycle with the same force regardless of the bolt and carrier's recoil force level. Two independent cycles in play... one rearward and one forward.

You may very well have a damaged striker spring in your system... they can get crushed... and if damaged it might nor provide sufficient return impulse to the bolt... causing miss feeds. HOWEVER, since this is a .308 (is that right?) magazine feed lip geometry and the .308 cartridges might come into play... do you get the failures on all mags? How many have you tested in your gun?

Food for thought..

Best of luck...

WallyG.