Windham Weaponry announced new uppers that allow the shooter to quickly change calibers from 5.56 NATO to either 300 BLK or 7.62×39. The uppers are called MCS, or Multi-Caliber System. Currently, two are being produced: MCS1 and MCS2.

The MCS1 has a complete 5.56 NATO upper assembly, and comes with a swappable barrel for the 300 BLK. The MCS2 has a complete 5.56 NATO upper and 7.62×39 quick change barrel, plus a bolt carrier group and magazine for the Russian cartridge.

Readers may notice that the forend retaining system looks similar to the system used by MGI on the Hydra line of rifles. I exchanged e-mails with a Windham Weaponry representative about the new uppers. He confirmed that the Multi-Caliber System uses technology licensed from MGI, and that the two companies have had a long-standing association.

The MCS1 has a suggested retail of $899, while the MCS2 has a suggested retail of $999.