I thought the Aussies finally got it fixed with helical cuts.
The sand cuts were a Brit development, their improvement on the first batch of FAL test rifles they got from FN. All the *Commonwealth* rifles used by former British colonies/possessions had the sand cuts, including the Canadian C1 and C2, Indian Ishapore-built 1A and 1A1 rifles, the Australian Lithgow-produced L1A1 and L2A1, and British-produced L1A1s [Enfield and BSA, from about 1954 on] and most Israeli rifles- which were *metric* pattern, not *inch* or *Commonwealth.*
The Rhodesians used both L1A1 rifles sent their prior to their Unilateral Declaration of Independence, and after that, mostly metric pattern rifles, particularly South african R1/R2 versions- without sand cuts.
The Australian L1A1 SLRs [pronounced *slurs* by the Digger troopies] worked fine in mud. I wasn't around them anywhere operational where there was that much sand [there's plenty to be had out back of Alice around Pine Gap!] so I can't say how that might have worked out. But my Lithgow L1A1, now fitted with a DSA L1A1 lower receiver, works pretty well in the grit.