The 6.5 Grendel is in many military small arms enthusiasts’ eyes the ideal military caliber, in theory combining the best characteristics of both 7.62mm and 5.56mm rounds. However, in the thirteen years since the round’s introduction, it has found little if any traction with actual military users – until now. It seems that the Serbian government has quietly adopted the “slow and steady” six five earlier this summer. From Novosti Online:

SPECIJALCI Serbian Army will be next year armed with the new US NATO modular rifles 5.56 and 6.5 millimeters. Procurement procedures and necessary tests should be completed by March next year, when the new weapons in the hands of the military and counterterrorist protivdiverzanata Special Brigade.

Purchase of new rifles, as explained in this unit, the continuation of the process of equipping with modern armaments, which began in 2008. Purchase of modern military equipment is the result of mounting tensions in the world and the intentions of the state leadership to prepare a response to the security threats

Additional clarification from Mondo:

During the shooting are tested modernized automatic rifle 7.62 mm and 5.56 mm, a new type of automatic sniper rifles and machine guns 6,5 mm “Grendel” modernized sniper rifles 7.62 mm “Lapua” guns and modernized. The new and modernized weapons from the “Zastava arms” is equipped with the new generation of optical and electronic sighting system produced in “Teleoptik gyroscopes”, “sensor INFIZ” and “Sova”, while a new generation of ammunition for the weapons produced Uzice Prvi Partizan

It must be noted that this is not a nation-wide adoption of the round, rather adoption by the Serbian Special Brigade only, and only in a limited role for sniper/designated marksman rifles. Still, this is a very significant victory for 6.5 Grendel proponents everywhere, and it also introduces the possibility of real battlefield data on the squat, short 6.5 round, where previously no data was available.

The 6.5 Grendel is an intermediate cartridge designed for AR-15-length rifles, requiring a change of bolt, barrel, and magazine. In exchange it provides greatly increased retained energy at long range vs. the 5.56mm, and at extreme ranges (over 900m), it even exceeds the 7.62 NATO in this respect. Thanks to its 11.3mm case head and rim dimensions, which it shares with the 7.62x39mm Soviet round, the 6.5 Grendel has made a natural partner for the AK family of rifles, and it seems to be Zastava-made AK pattern weapons in this caliber that have been adopted by the Special Brigade (article texts reference “modular American rifles”, but photos all show Zastavas). Serbian ammunition manufacturer Prvi Partizan will reportedly be the supplier for 6.5mm ammunition, which it is rumored is made to a slightly different specification than SAAMI-standard 6.5 Grendel.