Australian International Arms - AIA M10 No. 4 Mk. IV

[Bruce_in_Oz]

The problem of "sticky" cases in these rifles is a function of the ammo.

The heat of firing melts a little bit of the lacquer on the neck. This will generally re-solidify BEFORE you can open the bolt and thus, extraction starts to get sticky. You will find the same happens to Norinco and BRNO / CZ bolt actions with this ammo.

AK and SKS type actions open SO fast that the case is red-hot on extraction and ejection and thus the lacquer is still soft. They still accumulate a bit of lacquer fouling, and should be cleaned "thoroughly" from time to time..

Try the recently available Russian-made grey "polymer" coated stuff; it seems to not melt in the same way.

The WORST stuff I ever encountered for this problem was the "chocolate brown" lacquered stuff that came in pale green boxes of 20. This stuff appears to have been made "for export" to non-military customers. The "dark olive" coated Chinese "surplus" ammo seems to be less of a problem too. This usually came either in ten-round strippers or bundled in the classic "plain, brown wrapper", both in big "sardine tins", two to a wooden crate.

Even some of the "copper-washed" stuff can cause problems because the copper "plating" is itself protected by a thin layer of clear lacquer.

Plain brass as per PMC or Yugo stuff , etc, is perfect.