HK MR762 A4

The HK MR762 A4 is Heckler and Koch’s premium gas-piston 7.62 AR-10 rifle, delivering full-power .308 performance with the same engineering that made the MR556 famous. Built around a cold hammer forged cannon-grade steel barrel with an adjustable two-way gas block and a modern M-LOK handguard, the HK MR762 A4 is made for shooters who want serious range and authority without giving up reliability. This is a big-bore battle rifle with HK’s obsessive quality baked in.

What the HK MR762 A4 Brings to the Table

Chambered in 7.62 NATO and .308, this rifle steps up from the 5.56 class with substantially more energy on target, making it a strong choice for longer ranges, larger game, and situations where you want more authority per shot. It is an AR-10 pattern rifle, so it carries that added power in a familiar, ergonomic package that feels natural to any AR shooter.

Like its smaller sibling, the MR762 wears a 16.5 inch cold hammer forged cannon-grade steel barrel. In HK’s 12,000 round test, that barrel technology outperformed a mil-spec chrome-lined barrel in both accuracy and durability, and HK backs it with a lifetime barrel warranty for real peace of mind.

Features That Set the HK MR762 A4 Apart

• Chambered in 7.62 NATO and .308 for full-power range, energy, and authority
• 16.5 inch cold hammer forged cannon-grade steel barrel backed by a lifetime warranty
• Short-stroke gas piston system for cleaner, cooler, more reliable operation
• Adjustable two-way gas block for precise tuning to ammunition and suppressor use
• Modern M-LOK handguard for a lightweight, flexible accessory mounting platform
• Robust steel construction engineered for hard, sustained use in the field

Specifications Woven Into the Build

The short-stroke gas piston system is what sets the HK MR762 A4 apart from typical direct-impingement AR-10 rifles, keeping gas and fouling away from the bolt carrier so the action stays cleaner and cooler. In a full-power .308 platform, that reliability advantage is especially welcome during long strings and hot conditions.

The adjustable two-way gas block lets you dial the rifle in for your chosen loads and for suppressed shooting, while the cannon-grade steel barrel provides the accuracy and longevity HK proved in testing. The M-LOK handguard rounds out a modern, capable package built for the long haul.

Practical Use, Care, and Compatibility

As an AR-10 pattern rifle, the HK MR762 A4 works with compatible .308 magazines, optics, and M-LOK accessories, so building it into a precision or defensive system is straightforward. Clean the piston components and chamber regularly, keep the rifle lubricated, and it will reward you with dependable, accurate performance season after season.

Learn more about the maker at HK, and when you want to compare .308 rifles, browse our full firearms collection to see how it stacks up.

Powerful, reliable, and backed by a lifetime barrel warranty, this HK is a premium .308 you can trust. Like every firearm, it ships to your local licensed dealer for transfer after your background check.