The Marine Corps’ long, sometimes twisted, relationship with the M16 rifle is slowly coming to an end.

On Monday, the Marine Corps Times reported that the rifle is only a few signatures away from being phased out from front-line units and relegated to a support role. The move, which follows a similar one by the Army, comes as the Marine Corps implements its new small-arms modernization strategy.

“The proposal to replace the M16A4 with the M4 within infantry battalions is currently under consideration at Headquarters Marine Corps,” Maj. Anton Semelroth, a Marine spokesman, told the Marine Corps Times in an e-mail.

The weapon replacing the M16, the M4, is a smaller, carbine variant of the M16. Aesthetically the M4 looks only slightly different, with a collapsible stock and shorter barrel. And while the M4 also shoots the same sized bullet as the M16 — 5.56mm — the real benefits come from its reduced weight and portability.

At 7.5 pounds — a pound lighter than the M16 — the M4 fits nicely with the age-old infantry adage: “ounces equal pounds, pounds equal pain.” Additionally, the M4’s smaller size is ideal for close quarters combat and vehicle operations.

U.S. Marines with the 15th Marine Expeditionary Unit’s Maritime Raid Force advance on their targets while firing M4 carbine rifles on the flight deck of the USS Essex during training off the coast of San Diego in February 2015. (U.S. Marine Corps)

The Marine infantry’s adoption of the M4, however, is not completely new. The weapon has been fielded for quite some time, just not every Marine has been lucky enough to have one. In the past M4’s were generally issued to leadership while the average rifleman carried an M16.

Issuing the remaining Marine infantrymen with M4s will not cost the Marines a dime, as the Marines have the needed 17,000 M4s in stock, according to the Marine Corps Times.

The only drawback to using a M4 over the M16 is that the M4’s shorter barrel sacrifices accuracy out towards the maximum effective range of the rifle—500 meters. That is largely a moot point because at 500 meters the 5.56mm bullet fired by both the M16 and M4 is next to useless.

U.S. Marines from the Black Sea Rotational Force run a small arms range with Georgian Armed Forces using the M4 carbine rifle during Exercise Agile Spirit 15 at Vaziani Training Area, Georgia, July 10, 2015. (U.S. Army)

During the Vietnam war, when the M16 was first issued to U.S. troops, the Marines were some of the late adopters. In the early part of the war, Marine grunts hefted the M14, a grandson of sorts of the M1 Garand that was used in World War II and Korea.

The M16 of the Vietnam-era, though aesthetically similar, is not the M16 of today. The rifle of the 1960s was plagued with malfunctions due to issues with ammunition, corrosion resistance and other factors, as detailed in this excerpt from the book “The Gun.” Today, the M16 is not without its skeptics, however after various upgrades and modifications it is vastly more reliable and generally well-liked among current troops.