The M87R is an anti-materiel rifle of US origin. It was developed in the 1980's by McMillan and produced by Harris Gun Works. The M87R took part in the trails that led to the widespread addoption of anti-materiel rifles in US service. Although the M87R proved to be more accurate, the M82A1 was chosen since it was semi-automatic. For anti-materiel use a high rate of fire was deemed more useful than better accuracy.

The M87R may be regarded as an upscaled version of the 7.62x51mm Harris M86 bolt action sniper rifle. The M87R uses a larger and reinforced fiberglass chassis which holds the very long and thick barrel and much larger bolt action mechanism. A large pepperpot muzzle brake is fitted and a bipod is standard. Besides the baseline M87R a folding stock model and a lightweight model were also developed.

The M87R is a bolt action rifle that fires the 12.7x99mm NATO round from a 5 round detachable box magazine. Later on 10 round magazines were introduced and 20 round magazines are rumored to exist. The accuracy is very good and the effective range is over 1.5 km.

The M87R and its variants were sold to US government agencies and exported to various nations, including France, Italy and Turkey. Since Harris Gun Works is no longer trading since the late 1990's the M87R is no longer available. An improved model is sold by McMillan as the TAC-50.