When the US went to Afghanistan in 2001 and later Iraq in 2003, the M4 just wasn't good enough up against Soviet-era stockpiles of AK-47s which fire the old reliable 7.62x39mm ammo which was plentiful. US Army troops began to pick-up the foreign weapon as back-up until ordered NOT to use them at all. A solution had to be found to counter and that was the joint German-US XM8 which was highly favored by US forces in the region. However, adoption was again denied by Congress in 2006, infuriating HK, and disappointing the troops. The move was political and ensured Colt was bailed out once again on military arms (having failed a third time to deliver a decent ACR). The Germans came right back with the HK-416 in 5.56mm OR the HK-417 in 7.62x51mm. Yet another development was already in the works by FNH USA (licensed FN manufacturer). A weapon in multi-calibers of 5.56mm, 6.8mm, and 7.62x51mm PLUS 7.62x39mm (to take Soviet mags). This was the FN SCAR which ended up in 7.62x51mm for Army SFs and SOCOM Ops. The weapon debuted in Afghanistan and immediately made a difference fighting insurgents and terrorists alike. The weapon is heavier than the XM8 by almost 1 lb (8.5 vs 7.6), has multiple Picatinny railings for accessories, new mags, and either fixed or swinging butt. Very tough and resilient to the ME environment it is favored by US troops. But the weapon is not main issue, the US Army still stuck with the rotten M4 and the ACR competition still open. Several US companies like Bushmaster's bullpup ACR and Robinson Arms ACR are competing against 3 German weapons. Colt simply can't seem to break from the M16 series architecture and their ACRs lack innovation and engineering skill that the Germans put into their weapons. The SCAR is doing fine as a SPECOPS weapon, but no true ACR has emerged to replace the M4.