Within the Marine Corps veteran community, there are few subjects more prone to good-natured ribbing than the modern generation’s reliance on the standard issue Marine rifle combat optic, commonly referred to as an RCO. These 4x magnification rifle gunsights have been a part of every Marine’s standard rifle loadout for years now, but among old timers, the use of an RCO, rather than the rifle’s traditional iron sights, is just another sign of the Corps’ softening over the years. Now, the Marine Corps may actually run out of the standard issue optics in as little as six months.

“Based on the current sustainment model, the shortfall will have a critical impact on both Marine Corps Recruit Depot Parris Island and The Basic School within six months and Weapons and Field Training Battalion, Edson Range within 12 months,” the Marine Corps said in a recent press release.

The RCO utilized by the Marine Corps is a modified Trijicon ACOG (Advanced Combat Optical Gunsight) that utilizes dual illumination technology that incorporates a combination of fiber optics and self-luminous tritium.

According to Trijicon:

This allows the aiming point to always be illuminated without the use of batteries. The tritium illuminates the aiming point in total darkness, and the fiber optic self-adjusts reticle brightness during daylight according to ambient light conditions. This allows the operator to keep both eyes open while engaging targets and maintaining maximum situational awareness.

The Marine Corps is widely believed to produce the most proficient long-range shooters of the U.S. military’s conventional forces. Marines are required to engage targets as far away as 500 meters as a part of basic rifle qualification requirements, a distance more than 200 meters further than U.S. Army soldiers are required to shoot. Of course, every branch takes a slightly different approach to rifle qualifications and the standards to qualify tend to shift from time to time.

That 500-meter distance isn’t a recent addition to the Marine Corps’ rifle qualification standards, and as those aforementioned “old timers” can attest, hitting a silhouette target at that distance with iron sights requires a very different approach than it does with a 4x magnification RCO. Although RCOs are notably rugged and can withstand a great deal of abuse, many older Marines and veterans attribute their affinity for their old iron sights, at least in part, to their dependability.

The Marine Corps seems to be suggesting the RCOs have held up in the fleet, but are wearing out rapidly in training units that have a far higher rate of turnover. This suggests the problem may not really be the RCOs, but rather the ways in which they’re being treated, maintained, and stored. That means the Corps likely won’t be making the shift back to iron sights any time soon (or ever), despite concerns about RCO shortages.

“This highlights a need to develop a use and care policy for [entry-level training] in order to reduce shortfalls and a long-term sustainment model for the total force,” the Marine Corps press release states.