HOT
OpticPrimary Arms
SIG Sauer Romeo MSR Gen 2 Red Dot Sight - 2 MOA
2 MOA dot, 40,000-hour battery, M1913 Picatinny mount
Check price at Primary Arms →Gun parts worth buying, and where to get them
A short list of parts, optics and complete build sheets from Palmetto State Armory, Primary Arms, Brownells and MidwayUSA. Every link goes to the store's own product page, so the price you see there is the real one.
WHAT CAN I BUILD FOR…
8 builds
6 builds in reach
Grouped for a $650 budget. The slider that changes it needs JavaScript.
Comfortably in range
In range: Ruger 10/22 In range: Glock 19 In range: Glock 17Doable, but tight
Tight: SIG P320 tight Tight: AK-47 tight Tight: 1911 tightOut of reach at this budget
Out of reach: AR-15
Out of reach: AR-10 / .308
Rough budgets. Check the store for today’s price.
How this works
We don't sell anything. We link to the stores that do.
1
We pick the parts
We hand-pick slides, BCGs, triggers, furniture and mags from the retailers builders actually use, and lay them out as complete build sheets, so you know what to buy, in what order, and where it's safe to save.
2
You click through
Each part links to the retailer's own product page. You check out on their site, not ours, and pay their price.
3
The store ships it
The retailer takes your payment, handles compliance, and ships your order like any other. Your warranty and support come from them, the people who actually made or stocked the part.
Disclosure: Some links on this site are affiliate links. If you buy through one, the retailer pays us a small commission. Your price is the same either way.
Build sheets
Pick a platform and we lay out every part you need to build it, with estimated prices and a running budget total. Check parts off as you buy and your progress saves on this device (needs JavaScript).
Each one also has a full write-up with the complete parts list, what needs an FFL, where to save and where not to: Glock 17 · Glock 19 · SIG P320 · AR-15 · AR-10 / .308 · AK-47 · 1911 · Ruger 10/22. All eight build sheets →
Glock 17 Build
9mm · Full-Size · parts from Brownells
PRO TIP: The frame is the firearm. A serialized OEM frame ships to a dealer, you do the background check there, and you own a normal transferable pistol. That's the route for almost everyone. Partially-complete ("80%") frames fall under a 2022 ATF rule that is still being litigated, and several states ban them outright; check current guidance and your state law before going that way.
ESTIMATED TOTAL $410–560 · STILL TO BUY $410–560
Glock 19 Build
9mm · Compact · parts from Brownells
PRO TIP: Same build as the 17, just compact, with a shorter frame, slide, and barrel. A great everyday-carry first build. Same frame rules too: a serialized frame goes through a dealer, and partially-complete ("80%") frames need a check of current federal and state law first.
ESTIMATED TOTAL $405–550 · STILL TO BUY $405–550
SIG P320 Build
9mm · Modular · parts from Brownells
PRO TIP: The P320 is built around the Fire Control Unit, and that little stainless chassis IS the serialized firearm. Grip module, slide, and barrel all ship to your door, so one FCU can become a full-size, carry, or X-series gun whenever you want.
ESTIMATED TOTAL $535–725 · STILL TO BUY $535–725
AR-15 Build
5.56 NATO · Carbine · parts from Palmetto State Armory
PRO TIP: This is the friendliest centerfire rifle build, since barrels come headspaced from the factory and the upper is basically drop-in. Stake that castle nut and gas key.
ESTIMATED TOTAL $670–910 · STILL TO BUY $670–910
AR-10 / .308 Build
7.62 NATO · Rifle · parts from Palmetto State Armory
PRO TIP: The big-bore AR. Pattern is everything, because DPMS/LR-308/SR-25 pattern and original ArmaLite AR-10 pattern do NOT mix, and DPMS Gen1 and Gen2 receivers differ again. Pick one lane, match upper, lower, BCG and barrel to it, and gauge headspace before you ever fire it.
ESTIMATED TOTAL $855–1,155 · STILL TO BUY $855–1,155
AK-47 Build
7.62×39 · AKM · parts from Palmetto State Armory
PRO TIP: Real kit-building means pressing a barrel and setting rivets, which is gunsmith territory. Most people start with a complete rifle or a barreled/riveted receiver, then upgrade the furniture and trigger. That honesty saves you a ruined receiver.
ESTIMATED TOTAL $575–775 · STILL TO BUY $575–775
1911 Build
.45 ACP · Government · parts from Brownells
PRO TIP: The 1911 is a fitting gun, not snap-together, so the sear, barrel, and safeties usually need stoning and hand-fitting. Budget for a gunsmith, or go slow on your first.
ESTIMATED TOTAL $585–795 · STILL TO BUY $585–795
Ruger 10/22 Build
.22 LR · Rimfire · parts from MidwayUSA
PRO TIP: The friendliest build there is, with no press, no fitting, and headspace that takes care of itself once the barrel is seated. Everything hand-assembles with a punch, and it's the best possible first build.
ESTIMATED TOTAL $355–480 · STILL TO BUY $355–480
NOTE: Every price here is an estimate to help you size a budget, not a live quote and not a price we can honor. Ranges are typical street prices; the only real number is on the retailer's own page. The one part that may require an FFL transfer is flagged on every sheet.
HOT
AR-15 UpperPrimary Arms
Battle Arms Workhorse Stripped AR-15 Upper - BLEM
Forged 7075-T6, cosmetic blem only, warranty intact
Check price at Primary Arms →NEW
TriggerPrimary Arms
MIMTAC CORE AR-15 Drop-In Trigger - 3.5lb Flat
Drop-in cassette, single stage, fits AR-15 and AR-10
Check price at Primary Arms →HOT
OpticPSA
Vortex SPARC AR 2 MOA Red Dot
2 MOA dot, 12 brightness settings, included multi-height mount
Check price at PSA →OpticPSA
Vortex Strikefire II Red Dot
4 MOA red/green dot, lower-1/3 co-witness mount
Check price at PSA →HOT
AR-15 BCGPSA
PSA 5.56 Nitride MPI Full-Auto BCG
MPI-tested, full-auto profile, nitride finish
Check price at PSA →AR-15 BCGPSA
Toolcraft Carpenter 158 Nitride Full-Auto BCG
Carpenter 158 bolt, nitride, staked gas key
Check price at PSA →AR-10 BCGPSA
PSA PA10 .308 Nitride BCG
DPMS-pattern .308, nitride finish
Check price at PSA →NEW
AR-15 LowerPSA
PSA "Stealth" AR-15 Stripped Lower
Forged 7075-T6, no rollmark, ships to your FFL
Check price at PSA →HandguardPSA
Midwest Industries Combat Rail 15" M-LOK
One-piece free-float, lightweight, M-LOK
Check price at PSA →HOT
Weapon LightPSA
Streamlight ProTac HL-X Pro 1000lm
1000 lumens, rail mount, USB multi-fuel
Check price at PSA →Weapon LightPSA
Streamlight ProTac HP-X Pro 800lm
800 lm, long-throw beam, rail mount
Check price at PSA →Weapon LightPSA
Streamlight ProTac Rail Mount HL-X 1000lm
1000 lumens, fixed rail mount, tail cap or pressure switch
Check price at PSA →GripPSA
Magpul MOE SL Grip (AR15/M4)
Slimmer drop-in AR grip, anti-slip texture
Check price at PSA →NEW
GripPSA
Magpul MOE K2-XL Grip
Steeper grip angle, aggressive texture, AR-10/AR-15
Check price at PSA →HOT
MagazinePSA
Magpul PMAG 30 GEN M2 (5.56)
30-rd, 5.56, anti-tilt follower, USA-made
Check price at PSA →MagazinePSA
Magpul PMAG 30 AK MOE (7.62x39)
30-rd, 7.62x39, fits AK / AKM
Check price at PSA →Muzzle BrakePSA
Midwest Industries 5.56 Muzzle Brake
3-chamber, 3.6 oz, 100% USA-made
Check price at PSA →Muzzle BrakePSA
Fortis RED Brake 5.56 (SS)
Stainless, full-auto tested, 2.4 oz
Check price at PSA →NEW
AR-15 BCGBrownells
Faxon 5.56 Mil-Spec BCG
Mil-spec carrier, nitride, properly staked gas key
Check price at Brownells →HandguardBrownells
Wilson Combat AR-15 M-LOK Handguard
Free-float M-LOK, black, multiple lengths
Check price at Brownells →NEW
Charging HandleBrownells
Breek Arms Warhammer MOD2 Charging Handle
Ambidextrous, oversized latch, AR-15
Check price at Brownells →GripBrownells
Magpul MOE Grip (AR15/M4)
The original MOE, storage core, drop-in
Check price at Brownells →HOT
OpticBrownells
Holosun ARO Enclosed 2 MOA Red Dot
Enclosed emitter, 2 MOA dot, rifle-ready
Check price at Brownells →OpticBrownells
Holosun HS515GM Red Dot + QD Mount
20mm micro sight, solar failsafe, QD mount included
Check price at Brownells →HOT
Weapon LightBrownells
Streamlight TLR-1 HP Weapon Light
Long-throw beam, rail mount, CR123 power
Check price at Brownells →MagazineMidwayUSA
Magpul PMAG 30 GEN M3 (5.56)
30-rd GEN M3, 5.56, anti-tilt follower
Check price at MidwayUSA →NEW
MagazineMidwayUSA
Magpul PMAG 10/30 GEN M3 (5.56)
Full-size body blocked to 10 rounds for capacity-limited states
Check price at MidwayUSA →Guides
Things worth knowing before you place your first order.
Build Guide
The $400 AR Build That Actually Runs
A full parts list from budget-tier options: what to save on, what to never cheap out on, and the one shortcut that keeps a first build from failing.
Read the guide → Buyer's NotesDo I Need an FFL?
One part on every build is legally the firearm and goes through a dealer. Everything else lands on your porch. Which is which, platform by platform.
Read the guide → Build GuideThe Tools You Actually Need
About $60 of tools builds a working AR-15. The $300 master kits pad the count with things you use once. The short list, and what to skip.
Read the guide → Buyer's NotesWhat "Blem" Really Means
Cosmetic scars, full function (usually). How to read a blem listing, what's actually wrong, and when it's free money.
Read the guide → Field NotesWhy First Builds Fail
Nine mistakes account for almost every dead first build, and eight are catchable on the bench for free. What each looks like, and the check that prevents it.
Read the guide → Buyer's NotesAR-15 Twist Rates, Decoded
1:7, 1:8 or 1:9? What twist rate actually does, which myths to ignore, and how to match it to the ammo you'll really shoot.
Read the guide → Build GuideAR-10 Pattern Wars
There is no standard AR-10. Three incompatible patterns share the name, and mixing them costs you a receiver you already transferred.
Read the guide → Field NotesCold-Weather Lube: What Survives −20°F
Most gun oil is rated for a garage in Georgia. What actually works at twenty below: specific picks, and the mistake that freezes your firing pin.
Read the guide →Glossary
Terms you'll run into on product listings.
FFL
Federal Firearms License: a serialized frame or receiver ships to an FFL holder, who runs the background check and transfers it to you. Every other part on a build sheet ships to your door.
80%
A partially-complete frame or receiver you finish yourself. Under a 2022 ATF rule (upheld by the Supreme Court in 2025, still being litigated) a kit sold with a jig or tooling is treated as a firearm and goes through a dealer like any other; several states ban the route outright. Check current guidance before buying one.
Blem
A blemished part: cosmetic marks only, full function, usually 20–40% cheaper, and free money if you don't mind a scuff.
BCG
Bolt Carrier Group, the heart of an AR's action. Look for HPT/MPI tested and a properly staked gas key.
LPK
Lower Parts Kit, every small part to finish an AR lower (trigger, safety, springs, and pins).
Stripped
Sold as the bare part (slide or receiver) with none of the internals. Cheaper, but you supply the guts.
Headspace
The critical fit between bolt and chamber. Some builds (AR, 10/22) are drop-in safe; others need gauging. Get it wrong and it's dangerous.
M-LOK
The standard slots for bolting rails, grips, and lights onto a handguard, modular and everywhere.
MOA
Minute of Angle, about 1 inch at 100 yards. How sights and scopes measure adjustment and accuracy.
Nitride
A hard, corrosion-resistant black finish (aka Melonite/QPQ). Tougher and cheaper than phosphate for BCGs and barrels.
Free-Float
A handguard that attaches only at the receiver and never touches the barrel, which means more consistent accuracy.
Castle Nut
The notched nut that locks an AR buffer tube to the lower. Stake it so it never backs out under recoil.
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