MK20 SDM

The **MK20 SDM** (Squad Designated Marksman rifle) is a semi automatic rifle designed to full fill the marksman role. It uses a rotating bolt and a direct impingement gas system. It is loosely based on Arlyne's AR-60, rebuilt in its original 7.62x51mm SDC caliber. Up to 60% of parts of the MK20 are interchangeable with the AR556 and MK16—everything but the upper and lower receivers, the hammer, the barrel assembly and the bolt carrier group.

## History

The MK20 is manufactured by Holt's Firearms Incorporated as a request from the Amphibious Panamoan Marine Corps in a Marksman rifle that is chambered for the 7.62x51mm SDC round, and utilising the AR308 platform.

Before mass production, Holt essentially took the current versions of the MK16A4's overall design layout, mechanism, and internal components and retrofitted with an upper receiver that is specifically for the 7.62x51mm SDC; however, designers pointed out that the fixed sight post can cause extreme obstruction when using Telescopic long range sights, so the fixed sight post is converted in favour of flip-up sights, and the gas block is no longer a sight post. It's lightweight construction makes it easy to use and manoeuvre with the weapon, with it's total weight of just **9.83** Pounds, with a fully loaded 20-Round magazine.

In February 6th 2006, it was finally finished and it was exclusively tested by the APMC. Although they were going to use as their DMR, they agreed except when the refurbished MK16A4 is introduced in 2009, where the old and new MK16A4s are capable of being an Assault Rifle at diverse ranges, and perform similarly to a 7.62mm Designated Marksman rifle in providing long range suppressive fire. This rifle was made to extend the range, power, precision and accuracy beyond the infantrymen's assault rifles and carbines.

Holt's Firearms Incorporated introduced the enhanced MK20 Mod 0 at February 6th 2011. It was then reaccepted into the APMC, while the Panamoan Army were interested to order 50000 MK20s. The MK20 SDM was used in Operation Sandstorm exclusively by the APMC Marines, with the MK20 SDM gaining a good reputation for ballistic performance, precision, muzzle velocity and stopping power. In July 4th 2019, the MK20 SDM and it's upgraded version is largely replaced by a heavily accurized and modernised version of the MN14 rifle, the Rubicon MK39 EMR, which had completely triumphed over the MK20 SDM, as the standard Marksman rifle of the Amphibious Panamoan Marine Corps (APMC) and the Panamoan Army, as it had better transportability and concealment, and a much better performance. The successful launch of the SPR Mod 0 has lead to the creation of the RIA-338 SASR.

### Operation Sandstorm

The MK-308 SPR is used by Jack Blackburn in Operation Sandstorm, It was his signature weapon throughout the operation; And always carries it on missions. He notably uses it for the intended role, alongside some sniper rifles just in case long range sniping is required in his missions.

### Black Pegasus

The MK-308 SPR was used by APMC Marines during the defence of Chroma City's perimeter, It kills in one shot at the said mission, and it is very common throughout the level, although the MK39 EMR is more commonly used. It is also used in "Hunting Party", alongside the AI L338 and the MK408 Interceptor, with an Epzayne MKIII telescopic sight, and Digital Woodland camouflage pattern.

## Design

The MK20 SDM uses a rotating bolt and a direct impingement gas system. It is loosely based on Holt's first AR556 prototype rebuilt in its original 7.62x51mm SDC caliber, although it's heavily based on the MK16A4. MK-308 SPR barrels were originally manufactured by Holt's Firearms Incorporated with its 5R (5 grooves, right twist) rifling, with twist 1:11.25. The heavy duty 20-inch (508 mm) barrel is free-floating, so handguards are attached to the front of the 9090 Titanium Alloy upper receiver and do not touch/tightly grip the barrel.

The MK20 Mod 0 also simply referred as the enhanced match rifle, utilises the newer STD-885 Picatinny Weaver rail system, rather than the older MK-308 SPR free-floating RAS, on the top of the receiver to accept different scope mounts or a carrying handle with iron sights (front sight mounted on the rail located on the forward end of the non-modular handguard). The match version is designed to shoot at a precision of 0.5 minutes of angle, which corresponds to 0.5-inch (13 mm) groups at 800 Meters.

The MK20 Mod 0 system is chambered for 7.62x51mm SDC and is designed for hi grade match-grade ammunition, classifying it as a sniper rifle. The MK-308 system includes the rifle, 20 round box magazines, QD (Quick Detachable) scope rings.

The MK-308 Mod 0 utilises an Rubicon HD 20 in (508 mm) match target barrel, along with a RIS (Rail Interface System) fore-end made by Rubicon Industries, consisting of an 11.35 in (288 mm) long match fore-end. The RIS allows for quick attachment/detachment of STD-785 components. The aluminised Nevium rail handguard makes no contact with the barrel forward on the receiver, allowing for extreme accuracy.

### Specifications

* Length: 1,118mm
* Caliber: **7.62x51mm SDC**
* Effective Range: 900 Meters
* Weight: **9.83** Pounds (Fully Loaded)