Mil-Spec buffer tubes have a slightly smaller outside diameter (1.148 inches) and feature rolled threads, whereas Commercial tubes have a larger diameter (1.170 inches) with cut threads. It is crucial to match your stock type to your tube type. We carry heavy-duty, impact-extruded 7075-T6 Mil-Spec buffer tube assembly kits 6061-T6 aluminum to ensure a flawless fit for your build and Commercial buffer tubes.
Your handguard length depends entirely on your barrel length and gas system layout. Carbine-length systems typically utilize 6.5 to 7-inch rails, mid-lengths use 9-inch rails, and rifle-length setups require 12-inch versions. Combat Hunting features a massive inventory of direct two-piece drop-in M-LOK handguards, Picatinny / Quad Rails KeyMod and lightweight free-float rail systems to maximize your accessory space on all Mil-Spec AR-15, M4, LR-308, AR-10, or LR-308 platform rifles.
No, many components are not interchangeable. While fire control groups, pistol grips, triggers, and receiver extensions (buffer tubes) are universally compatible, specific components like the bolt carrier group (BCG), charging handles, upper/lower receivers, barrel nuts, and muzzle devices feature completely different dimensions. We offer specialized DPMS LR-308 parts, heavy 308 buffers, and 5/8x24 muzzle brakes specifically for large-frame builds and more.
Yes! Our Mil-Spec AR-15 parts and custom-colored furniture kits are direct, drop-in upgrades designed to fit standard Mil-Spec platforms perfectly. Whether you are upgrading a Smith & Wesson M&P 15 Sport (I, II, or III), a Colt M4 carbine, a Palmetto State Armory PA-15, or a Springfield Armory SAINT, our stocks, quad rails, and extended controls will install seamlessly without gunsmith modifications.
Muzzle device thread patterns are strictly defined by caliber size to prevent dangerous installation errors. Standard .223 Remington / 5.56 NATO barrels use a 1/2x28 TPI thread pattern, which is also shared by most AR-9 (9mm) setups. Conversely, 300 Blackout and .308 Win/7.62x51 barrels utilize a larger 5/8x24 TPI thread pitch. Always double-check your barrel thread specifications before buying a muzzle brake or flash can.
A complete lower parts kit contains all the essential internal pins, springs, detents, fire control group components (trigger and hammer), pistol grip, and safety selectors required to turn a stripped lower receiver into a functional firearm frame. Our custom-colored anodized lower upgrade kits allow you to dress up your rifle while ensuring reliable performance. Our AR-15 Lower Parts Kit are in enhanced with a special accuracy wedge to remove receiver slack, representing the ultimate upgrade for stability and precision for your build.
The AR platform utilizes six primary buffer tube configurations:
• Mil-Spec Carbine: Features a 1.148" outside diameter and an adjustable indexing track. It is the modern industry standard for adjustable stocks.
• Commercial-Spec: Features a larger 1.170" diameter with cut threads and an angled rear profile. Requires specialized commercial stocks.
• Pistol Tubes: A completely smooth, round cylinder with no bottom alignment holes, ensuring compliance with ATF regulations by preventing stock attachment.
• A2 Rifle: A long, smooth tube designed specifically for fixed stocks, utilizing full-length rifle springs and heavy 5.2 oz buffers for maximum cycling stability.
• A1 Style / Fixed with Adapter: Essential for retro Vietnam-era M16A1 clone builds. Our custom kits include a specialized rear adapter spacer block, allowing you to easily adapt fixed stock lengths of pull on full-length rifle extensions.
• A5 Intermediate: Shares the standard Mil-Spec diameter but features a 3/4" longer internal cavity to house rifle-length springs for significantly softened recoil.
Combat Hunting stocks a massive inventory of heavy-duty, impact-extruded receiver extensions to match any custom build style.
A complete pistol kit bundles the five core pieces needed to assemble a functional rear cycling unit: a dedicated smooth pistol buffer tube (receiver extension), a standard carbine recoil spring, a reciprocating buffer weight (typically 3.0 oz), a steel castle nut, and a receiver end plate. Many premium kits also include a heavy-duty foam sleeve cover that slips over the exterior of the aluminum tube to provide a comfortable surface for a clean cheek weld.
Mechanically, the internal system operates identically to a standard rifle by housing the recoil spring and buffer weight that allows the bolt carrier group (BCG) to cycle. However, because short-barrel AR pistols dump gas back into the action much faster and more violently than full-length rifles, a pistol buffer assembly often requires fine-tuning. Upgrading the internal buffer to a heavier H2 or H3 weight is a common and effective way to absorb extra recoil energy and prevent aggressive cycling or extraction failures.
The primary purpose of a dedicated pistol buffer tube is strict adherence to federal firearms laws and ATF guidelines. A standard carbine tube features a bottom adjustment rail that allows a traditional shoulder stock to click directly into place. Attaching a shoulder stock to a firearm with a barrel shorter than 16 inches creates an illegal Short-Barreled Rifle (SBR). A true pistol tube features a completely smooth round exterior that makes attaching a standard stock impossible without permanent, complex modifications, cleanly proving your intent to build a legal, compliant AR pistol.
No, AR pistol buffer tube lengths vary by design footprint. Standard Pistol Tubes measure 7.25" to 7.50" to match standard carbine dimensions, allowing the use of universal carbine springs and buffers. Extended A5 Pistol Tubes measure 8.00" to 8.50" to utilize heavier rifle-length setups for reduced recoil. Ultra-Compact Micro Tubes measure 5.00" to 6.00" for maximum portability but require proprietary short buffer weights and specialized flat-wire springs to function reliably without short-stroking. Combat Hunting stocks heavy-duty, impact-extruded pistol buffer tubes designed to fit standard lower frames flawlessly in Standard Pistol and extended length assembly kit with foam pad.
