Builds & Assembly Guides
Step-by-step upper builds, torque specs, headspacing, and tools.
How to Build a Dedicated Night Hunting Upper
Plan a dedicated night hunting upper for your AR-15: caliber, barrel, handguard, muzzle device, optic mounting and lights, plus why state laws matter first.
More Builds & Assembly Guides
How to Build a Home Defense Upper That Balances Size and Reliability
Plan a home defense AR-15 upper that stays compact without giving up reliability. Compare barrel length, gas system, caliber, muzzle device and lighting.
How to Choose a Muzzle Thread Pitch for Your Upper
Match your AR-15 thread pitch to caliber, bore size and muzzle device. Learn when 1/2x28, 5/8x24 or big-bore threads fit the upper you are building.
How to Get a Competition Upper Ready for Your First Rifle Match
Prepping a competition AR-15 for your first match? Learn how to inspect, lube, zero and test your upper so match day is about shooting, not fixing gear.
How to Replace the Barrel on Your AR Upper
Plan an AR-15 barrel replacement the right way: tools, teardown order, gas block and nut install, headspace checks and when to hand the job to a gunsmith.
How to Test Your Upper's Accuracy With Group Shooting Drills
Measure AR-15 accuracy the right way. Learn how to set up group shooting drills, control variables, measure groups and read what your upper is telling you.
What Comes in an Upper Parts Kit and When You Need One
Learn what an upper parts kit usually includes, how forward assist and dust cover parts work, and when a stripped AR-15 upper actually needs one.
What Tools You Need to Assemble an Upper at Home
The essential AR-15 build tools for assembling an upper at home, from a vise block and armorer's wrench to a torque wrench, punches and headspace gauges.
Which Is Better for a First Build, a 14.5 or 16 Inch Upper?
Weighing a 14.5 barrel against a 16 inch upper for your first AR-15? Learn the NFA rules, pinned and welded muzzle devices and which length is simpler.
Why a 50 Yard Zero Works So Well on a Carbine Upper
Learn why a 50 yard zero suits carbine-length AR-15 uppers, how the trajectory behaves, how to confirm it at distance, and when another zero makes sense.
Free-Float vs Drop-In Handguards: Which One Do You Need?
Free-float handguards improve accuracy and mounting options; drop-in handguards install fast and cost less. Here's how to choose.
338 ARC Suppressed Builds - What Works Best?
Gas tuning, barrel length, BCG, and buffer weight for a reliable 338 ARC suppressed build. Shop complete uppers at AR15Parts.com. Call us at (888) 706-0633.
AR-15 vs AR-10 Parts Compatibility: What Shares and What Doesn't
AR-15 and AR-10 look similar but share almost no parts. Here's exactly what interchanges and what requires the larger platform.
Fixed, Adjustable, and Folding Options Explained - AR-15 Stock Guide
Fixed, adjustable, or folding AR-15 stock? Learn which fits your build and use case, then shop parts at AR15Parts.com. Call (888) 706-0633 for expert help.
How to Build an AR-10 - Parts, Process, and What to Expect
Learn the AR-10 build process from platform selection to final assembly. Shop AR-10 parts at AR15Parts.com. Call (888) 706-0633 or get a free parts list today.
How to Choose the Right Gas System Length for Your AR-15
Pistol, carbine, mid, or rifle-length gas system? Match your barrel correctly. Expert AR-15 build guidance from AR15Parts.com. Call (888) 706-0633.
Key Differences Every Shooter Should Know About AR-15 vs AR-10
AR-15 vs AR-10 compared side by side: calibers, size, and parts compatibility. Find the right platform for your next build. Shop uppers at AR15Parts.com.
Types, Features, and Installation - Your AR-15 Collapsible Stock Guide
Compare AR-15 collapsible stock types, key specs, and install steps. Mil-spec vs commercial, LOP, and more. Shop at AR15Parts.com or call (888) 706-0633.
What Is a Bolt Carrier Group and Why Does It Matter for Your AR Build?
Learn what a bolt carrier group does, how it works, and how to pick the right BCG for your AR-15 build. Shop BCGs at AR15Parts.com or call (888) 706-0633.
AR-15 Cycling Issues: The Full Troubleshooting Guide
Short strokes, failures to feed, stovepipes, and bolt-over-base: here's how to diagnose and fix the most common AR-15 cycling problems.
How to Clean an AR-15 Upper Receiver: The Full Guide
AR-15 uppers need less cleaning than most people think, but they do need cleaning. Here's the sensible full-cleaning routine that works.
AR-15 Barrel Break-In: Does It Actually Matter?
Barrel break-in procedures range from elaborate rituals to 'ignore it entirely.' Here's what actually helps, what doesn't, and how to do it right.
AR-15 Headspacing: What It Is, When to Check, How to Do It
Headspace determines whether an AR-15 chamber and bolt fit safely with a given cartridge. Here's what it means, when to check, and how.
Adjustable Gas Blocks: When You Need One and How to Tune
Adjustable gas blocks let you dial in exactly how much gas your AR-15 uses. Here's when they matter and how to tune yours correctly.
Muzzle Brake vs Compensator vs Flash Hider: The AR-15 Guide
Muzzle brakes, compensators, flash hiders, and hybrids all serve different roles on an AR-15. Here's what each does and which one you need.
Cold Hammer Forged vs Button Rifled Barrels: Which Is Better?
Cold hammer forged and button rifled AR-15 barrels are made differently and last differently. Here's how they compare on accuracy, longevity, and cost.
BCG Coatings Compared: Phosphate, Nitride, NiB, DLC, and More
Phosphate, nitride, nickel boron, DLC, TiN, and NP3 all coat AR-15 bolt carriers. Here's how they compare on wear, cleaning, and cost.
Full-Auto vs Semi-Auto BCG: What the Difference Actually Means
Yes, a full-auto (M16) profile BCG is legal in a semi-auto AR-15, and it's the modern standard. Here's how it differs from a semi-auto BCG in weight, shroud, and reliability.
Will This Upper Fit My Lower? The AR-15 Compatibility Checklist
Any mil-spec AR-15 upper fits any mil-spec AR-15 lower, including 300 BLK, 6.5 Grendel, and 6mm ARC. AR-10 calibers like 308 and 6.5 Creedmoor don't. Full checklist inside.
AR-15 Upper Torque Specs Cheat Sheet
Every AR-15 upper receiver torque spec you need in one place: barrel nut, gas block, castle nut, muzzle device, and handguard fasteners.
AR-15 Charging Handle Guide: Standard, Extended, and Ambidextrous Options
Mil-spec charging handles work for most rifles. Extended latches help with gloves and optics, and ambidextrous handles suit lefties. Compare types, prices, and install steps.
How to Install an AR-15 Upper: Step-by-Step Guide
A complete walkthrough for installing an AR-15 upper onto a lower receiver, plus torque specs, headspacing basics, and common mistakes to avoid.