The AR-15 took its beginnings from the military M16 rifle. The goal at the M16’s creation was to be the lightest rifle available for battle. That first M16 — the M16A1 — met the military weight requirement, coming in at 6.37 pounds. The commercially produced Colt counterpart (AR-15A1) weighed the same. With continuous improvements — a heavier barrel and longer buttstock — came some not necessarily desired weight.

The current Colt AR-15A4, featuring its round forend and railed upper receiver with detachable carry handle, now weighs 7.71 pounds. And the heavy barrel M4 carbines, such as Windham Weaponry’s HBC, weighs 7.45 pounds.

Many AR-15 rifles and M4 carbines are quickly turned into tactical operator’s weapons after purchase. Red-dot optics, lights, lasers and suppressors are common enhancements. But the original triangular fiberglass (and later rounded) handguards of the AR-15A1 and A2 had no place to readily affix extra equipment. Neither system was satisfactory, and people were demanding the ability to mount more gear. So the AR-15 quad rail forend was introduced. The quad rail could accommodate vertical foregrips and nearly anything else, including 37mm grenade-launcher units! While these quad rail units offered the ultimate in versatility for carrying and positioning accessories, they also added more weight.

Key Mod and M-Lok Rails

Eventually, users and manufacturers realized festooning the forend of an AR-15 with Picatinny railing was unnecessary and most shooters could get by with far fewer mounting points. This was especially true after the gear itself got smaller. Two new forend systems were introduced to accommodate short Picatinny rail segments: the Key Mod, introduced in 2012, and the M-Lok, introduced in 2014.

These allowed multiple mounting points of various accessories while reducing overall weight and, maybe most importantly, forend diameter. These new, sleeker systems allowed AR-15s and M4s to maintain the feel of handling like a sports car even with gear attached.

Today, AR users can reduce the weight further and improve the handling by taking the rifle down to the bare bones.

What Is a Skeletonized AR-15

With the advent of CNC machining and the use of carbon fiber to produce AR-15 parts such as receivers, forends and stocks, a whole new generation of AR-15s is emerging with heretofore unimagined construction: the Skeletonized AR-15.

The purpose of skeletonization is to shave every ounce of unnecessary weight from the lower receiver, stock and forend without reducing the platform’s strength. The result is the creation of customizable and individualized rifle art that is still fully functional.

Skeletonized forends are probably the most eye-catching of the skeletonized aftermarket features available. They have an almost wispy appearance. (I never thought that I’d use the word wispy in relationship to an AR-15.) And depending on the company and material used in the construction, forends, buttstocks and lower receivers are available in various colors. Many of the items available online are mil-spec as well, so they should easily fit any AR-15.

Is There a Downside to Skeletonized ARs?

Simple answer: yes. The M16 was developed as a battle rifle, designed and developed on the job for combat in the jungles of Vietnam. But for 20 years after the 9/11 attack, the M16 found itself in sandy desert combat. In contrast to minimizing points of dirt entry, skeletonization provides a myriad of openings for dirt to enter critical spaces.  This is especially true of skeletonized lowers. Think of dropping one into the mud or sand and having to clean that out.

Using a skeletonized AR-15 for competitive or recreational shooting should see less trouble. If your rifle is for emergency use or as a bugout weapon, perhaps stick to the original AR-15 design to keep the entry points of dirt to a minimum. Determining your rifle’s purpose will be the most important factor in determining design.