With its light bullets the M4 rifle lacks sufficient velocity and killing power in long-range firefights, leaving US troops outgunned by the Taleban and their AK47 Kalashnikovs and the old Russian SVD sniper rifle.
Britain has followed the US in investing in 400 new larger-calibre Sharpshooter rifles, which use a heavier 7.62mm round, and are effective at longer ranges. The weapon is expected to be deployed in Afghanistan, alongside the standard rifle, by the end of the month.
I trained on both the 7.62mm SLR and the 5.56 M16. Although I never fired either in anger I always believed the 7.62 would be far more effective in battle. Logistics wise the smaller M16 rounds would be easier to distribute.