DMR is short for Designated Marksman Rifle. These are semi-automatic rifles that effectively fill the gap between assault rifles (used up to approx. 300-400 metres) and sniper rifles (usually from 600-800 metres).
This role has previously been fulfilled by squad snipers. These received selected ordnance weapons which were already noticed during the shooting tests in the factory by an above-average precision. These weapons were often equipped with a fixed rifle scope (e.g. G3ZF).
Umarex/VFC G3 GBB at Umarex at the IWA 2019
Many armies now use 5.56×45 NATO caliber assault rifles. At 500-600 meters, it has a lower precision and effectiveness than the previously used 7.62x51mm NATO cartridge. Therefore DMR rifles in 7.62mm caliber were often procured. Logistically this means, of course, that the infantry group has to keep another type of ammunition in stock. However, many armies accept this. In 2016 the Bundeswehr purchased additional rifles in the old Nato caliber under the designation G27P (based on the HK 417). These serve as heavy assault rifles and complement the G28 as currently used DMR.
DMR and Airsoft
In general, a well built MP5 does not differ from a G3, with the exception of the barrel length. However, this has less influence on a 6mm ball than a good hop-up and a tight system. Therefore the use of DMR’s is often controversial. In the rules of many airsoft areas these weapons are described exactly. The length of the weapon, the type of optics, or even the original model are relevant. This prevents someone with a heavily modified MP5 from playing with 2 joules and more than DMR.
Therefore, DMR’s may also have a higher energy if a larger safety distance is ensured.