The McMillan M86 (now Harris) was designed with military and security forces in mind, allowing for the ability to reliably and consistently deliver lethal firepower at long ranges in any climate or environmental working conditions. The M86 went on serve with both the Untied States Navy SEALs and Delta Force special forces groups with the first 460 or so of these systems being earmarked as such. Harris Gunworks purchased McMillan in 1995, changing the formal designation of the M86 to reflect this move.
The M86 utilizes McMillan engineering throughout, including the McMillan-based action, McMillan McHale adjustable fiberglass composite stock with recoil pad and the McMillan match grade heavy contour precision barrel. The rifle was eventually available in a variety of calibers that included 7mm Remington Magnum, 7.62x51mm NATO, .300 Winchester Magnum, .30-06 Springfield and .338 Lapua Magnum cartridges. Depending on the selected caliber, magazine counts differed from 3- (.300 Win Mag), 4- (.308 and .30-06), 5- and 10-round detachable magazines. Magazine types offered were either an internal magazine or a conventional detachable box. Optic options proved plentiful and included flashlights, low-light and night vision scopes. Despite its size, the M86 enjoyed a relatively light operating weight thanks to its fiberglass composite stock. An adjustable bipod (featuring full tilt and swivel control) was optional as was a detachable buttstock. Interestingly enough, no iron sights were afforded to the base weapon.
Externally, the M86 sported a simple and clean design. The near-vertical pistol grip was integrated into the stock and body. The bolt-action lever was set to the right side of the body with the segregated trigger group located just underneath. The barrel was seemingly featureless and extended forwards from the squared-off body while optics of virtually any type could be fitted onto the gun. The optional bipod could be folded backwards and up against the gun body for increased portability.