Block 2 IAR

$1,629.00 at Optics Planet · In stock

The Daniel Defense M4A1 FSP upper is the classic Block 2 foundation: a 14.5-inch cold hammer forged barrel with a Surefire SF3P pinned and welded to a permanent 16-inch barrel length, carbine gas, a pinned front sight post, and a full quad rail. The quad rail is the point here; its mass helps soak up heat during sustained fire, and the four Picatinny faces mount anything. The assembly includes Daniel Defense's M16-profile BCG and ambidextrous GRIP-N-RIP charging handle.

$155.00 MSRP

The Aero Precision M4E1 stripped lower is the most popular upgrade receiver for a reason. The threaded bolt catch pin installs with a hex key instead of a hammer and roll pin, the integrated trigger guard cannot snap off, and the upper tension screw removes receiver wobble against the DD upper for a tighter feel.

$275.00 at Optics Planet · In stock

The Partisan Disruptor is the heart of the build. It is a forced reset trigger with a three-position safety and a listed 3.75 to 4.1 pound pull. In its enhanced-semi mode the bolt carrier's rearward travel physically drives the trigger forward into reset, so follow-up shots come far faster than a standard trigger while each pull still fires a single round. It needs an H2 buffer at minimum, with H3 recommended, on a carbine-gas gun like this one.

$19.85 at Optics Planet · In stock

The Magpul MOE-K2 uses a steeper 17-degree grip angle that brings the firing hand closer to the body, which suits a squared-up stance and reduces wrist strain when running an aggressive, C-clamp hold during fast strings.

$95.00 at Optics Planet · In stock

The B5 Enhanced SOPMOD gives the widest cheek weld in B5's lineup at 11.8 ounces, with dual water-resistant compartments that each hold three CR123 cells. The wide comb supports your face under the raised holographic sight, and the battery storage keeps spares for the EXPS3 and light on the gun.

$789.99 at Optics Planet · In stock

The EOTech EXPS3 is the close-range half of this setup: a 68 MOA ring with a 1 MOA center dot, projected as a hologram so the dot stays 1 MOA once a magnifier goes in behind it. Thirty brightness settings cover daylight through night vision, the quick-detach lever lets the sight come off without tools, and the large window keeps both eyes open and the peripheral view intact during fast strings.

$629.99 at Optics Planet · In stock

The G33 is the 3x half. It rides a switch-to-side mount behind the EXPS3 and flips out of the optical path in a thumb sweep, so the rifle sits at true 1x by default and only picks up magnification for positive identification and precision past 200 yards. The pairing runs around 22 ounces with mounts, which is the weight cost of the versatility.

$129.95 at Optics Planet · In stock

The Magpul D-60 holds 60 rounds in a compact drum with a ratcheting loading lever and the proven Gen M3 feed tower. For a sustained-fire role, it keeps the FRT fed through long strings without the interruption of frequent 30-round reloads, at the cost of 46 loaded ounces hanging off the magwell.

$74.95 at Optics Planet · In stock

A rifle carrying a quad rail, a drum, and a magnifier needs a padded sling. The Blue Force Gear Vickers Padded runs a two-inch closed-cell foam pad inline with the webbing, so the weight rides across the chest instead of cutting into it, and the patented Quick Adjuster snaps between hands-free carry and a shooting position with one pull.