HK MR762 A4 SBR 13-Inch 7.62x51 NATO Rifle (81001054)

The Heckler & Koch MR762 A4 SBR is HK's factory short-barreled rifle (SBR) in 7.62x51mm NATO: a 13-inch, semi-automatic, short-stroke gas piston rifle and the civilian descendant of the HK417 battle rifle. HK USA lists it at 7.95 pounds without a magazine and 31.4 inches overall, and it ships with one 20-round magazine. This is a National Firearms Act (NFA) item.

Why HK builds a 13-inch 7.62

HK developed the HK417 with its own money, working directly with special operations personnel. The idea was 7.62mm power in a rifle that still handles like a carbine. HK catalogs the military rifle with 13-, 16.5- and 20-inch barrels, and describes the spread as running from house-to-house fighting to precise fire at distance.

The 13-inch is the short end of that family, the one built for close quarters. The German Army fields the 13-inch HK417 A2 in its G27 family. The same platform also produced the G28 marksman rifle and, in a lightened form, the U.S. Army's M110A1.

The MR762 is the semi-automatic version HK sells to American civilians. With the A4 SBR, the short barrel comes from the factory.

What the piston buys you

A direct-impingement AR-15-pattern rifle vents hot gas into the receiver to run the action. The HK uses a piston and pusher rod instead, so that gas and its carbon stay out front. HK says the result runs longer, needs less maintenance, and puts less wear on internal parts.

On a short 7.62 that matters, and it matters more with a suppressor. The A4 adds a two-position gas regulator, with one setting for unsuppressed fire and one for suppressed.

What is new in the A4

HK USA announced the A4 series in late 2024, replacing the first-generation MR762 A1. The lower receiver is now fully ambidextrous: bolt catch and release, magazine release, and a 45-degree selector on both sides. The handguard is a slimmer free-floating design with M-LOK (Modular Lock) accessory slots, and the stock is HK416 slimline furniture.

Then there is the barrel. It is cold hammer forged with a 1:11-inch twist, and HK guarantees the bore for life, a first for the company. Nathan Schueth, HK's director of business development, said it plainly: "You shoot it out, we'll replace it."

13-inch SBR or 16.5-inch rifle?

This is the rifle for the shooter who wants 7.62 in the smallest serious package: a suppressor host, or the starting point for a 13-inch HK417 A2 clone. It is semi-automatic only; the HK417 is select-fire.

If reach is your priority, look one step up. Our 16.5-inch MR762 A4 gives you more velocity and is not an NFA item. And if you want 6.5 Creedmoor range from a short barrel, the LMT Mk 24 (MRGG-A) is the one to study. Charlie's is a dealer, not a brand. We will tell you which one fits.

Before you order

• No sights included. Bring your optic and backups.
• It feeds from HK417/MR762-pattern magazines.
• A 13-inch 7.62 is louder than the 16.5-inch and gives up some velocity. That is the trade for the size.
• The A4 gas regulator and ambidextrous controls do not fit an A1.

This is the short 417, and it comes from HK's own factory. Add your optic and your suppressor, and your build is done. Questions on optics, mounts or a suppressor to match? Call us. HK, 7.62, NFA: we speak your language.

Specifications

Questions buyers ask

Is the HK MR762 A4 SBR the same as an HK417?
No. The MR762 A4 is the semi-automatic civilian descendant of the HK417; the military HK417 is select-fire. The two share the short-stroke piston design, and the 13-inch barrel matches the short HK417 A2 the German Army fields in its G27 family.

What changed from the MR762 A1 to the A4?
The A4, announced by HK USA in late 2024, adds a fully ambidextrous lower receiver, a two-position gas regulator, a slimmer M-LOK handguard and stock, and HK's lifetime bore guarantee. The A4 gas regulator and ambidextrous controls do not fit an A1.

Is the MR762 A4 SBR a good suppressor host?
It is built for one. The piston keeps gas and carbon out of the receiver, the regulator has a dedicated suppressed setting, and the muzzle is threaded 5/8x24.

What magazines does the MR762 A4 SBR take?
HK417/MR762-pattern magazines. HK offers them in 10 and 20 rounds, and the rifle ships with one 20-round magazine.

Should I buy the 13-inch SBR or the 16.5-inch MR762 A4?
Choose the 13-inch for the smallest package and for suppressed use. Choose the 16.5-inch for more velocity and a rifle that is not an NFA item. Both use the same A4 receiver, controls and gas system.

What comes with the rifle?
One 20-round magazine. Sights, optic and suppressor are not included.