Ongoing issues....extraction/ejection?

[Bruce_in_Oz]

Where, if anywhere, it it throwing the "empties", NATO-spec ball specifically? There are "minimum" regulator settings: "Unit level"; 4, 5 or 6. At Field Workshop level; 5 or 6. The general idea is to adjust the gas regulator until cases (fired prone) land about four or five feet away. If this cannot be achieved at those gas settings, there is something wrong; call the "gun-plumbers". If the brass is disappearing into the next county / province, etc., you need to open the regulator up a bit more.

If, on a warm-ish day, they are barely departing , or not leaving the ejection port with a bit of vigor, the problem will be gas, or lack thereof. This can be the result of:

1. An undersized port in the barrel
2. A misalignment between the barrel port and the gas block.
3. A badly worn gas block.
4. A badly worn gas piston. (Loss of hard-chrome coating was cause for replacement)
5.Too much gas venting via the regulator collar.
6. Gas cylinder (the thin steel tube) has incorrectly cut slots or has been incorrectly fitted.
7. Combinations and permutations of all of the above.

These are definitely NOT "shake and bake" bits of gear.

There was, in Oz, another "operation" in which the gas port in the block and barrel could be "cleared" to ensure there was plenty of gas arriving at the piston face, with the regulator still having "travel" in either direction.

That reference states:

"Gas vent may be cleaned using a No.42 drill (0.0935 inch diameter).

Another "modification" to the gas system:

The slots in the front end of the tube were to be "extended" and "radiused" to reduce cracking resulting from stress risers caused by the early "square-ended" slots.

Additionally, there was the application of a "corrosion-resistant" zinc coating to the threads of the gas cylinder to prevent corrosion and subsequent cracking of that tube. The stuff was a "2-pack" paste, (binder and zinc-powder filler) that had to be mixed frequently during the relatively short "work' time. The threads were to be wire-brushed free of phosphating before application. The brew dried fairly quickly, about ten minutes at room temperature.