The Nemesis is a large caliber sniper rifle and was devised
in 2001 by two former military, the retired US Marine Corps officer, James Owens
and the Swiss Chris Movigliatti. First prototype was tested only 3 months after
the design inception. In 2003, first production batch of rifles was made by
AMSD, a Swiss company, highly specialized in the design of precision military
light armament. The new weapon was officially christened as the OM 50 Nemesis (OM standing for names of the designers, 50 for caliber
and Nemesis for the ancient Greek goddess of justice and vengeance). The prime
niche for this new weapon is precision anti-material shooting for military and
police applications. The weapon can be configured as well for urban warfare as
for long range target operations. A civilian version exists also for long range
precision shooting. For this reason, the OM 50 Nemesis rifle features a fully
modular design with three basic versions, known as Mk I, MK II and Mk III
respectively. Each of these versions can be fitted with a variety of
quick-change barrels, of different profiles and lengths, as well as with
different add-ons (high efficiency muzzle brakes or detachable silencers /
sound moderators). Barrel lengths vary from 381 mm / 15 inches for short range
(urban) shooting against hardened targets and up to 838 mm / 33 inches for
accurate long-range shooting. Barrel change can be accomplished in the field in
less than 2 minutes, using a DIN screwdriver. All OM 50 Nemesis rifles are
built around the same aviation grade aluminium-alloy receiver and (steel) bolt
group with a manually operated, rotary bolt. Bolt heads lock directly into the
barrel extension with three radial lugs, relieving receiver from most of the
stress and providing constant headspace, needing no adjustment. Barrels are
free-floated, and are held in the receiver by a set of cross-screws. Trigger is
of two-stage type, fully adjustable. The forend is attached to the receiver.
Top of receiver is provided with one or more Picatinny type rails which can
accept a variety of telescope and other accessories (laser; Night Sight;
light). The top rail can be delivered with a 20 MOA to 40 MOA angle.

The OM 50 Nemesis Mk I have a manual feeding block, and feature an adjustable
fixed butt stock. It can be upgraded to the OM 50 Mk II configuration by taking
out the manual feeding block and replacing/adding (1) the 5-round detachable
box magazine, (2) the side-folding adjustable butt stock, (3) the folding bipod
(attached to forend) and (4) the rear folding monopod (attached to the butt
stock). Further upgrade, which includes extended forend with additional
Picatinny rails, constitutes the OM 50 Mk III configuration. Depending on the
mission, a particular version of the OM 50 Nemesis can be easily converted by
the operator to another (up and down), with installation or reinstallation of
necessary parts and modules.