Used Firearm Inspection Guide
Used Gun Inspection
Checklist
A platform-specific field inspection guide for buying used. Work through each section before you hand over money. Items flagged red are walk-away conditions — everything else is either acceptable wear or a negotiating point.
Inspection Tool
⚠ Immediate Walk-Away Conditions
- Obliterated, altered, or re-stamped serial number — federal crime to own
- Visible bulge in the barrel — catastrophic failure risk
- Cracked frame or slide — non-repairable structural failure
- Safety does not engage or disengage correctly
- Seller refuses to allow unloaded function check or bore inspection
- Evidence of amateur gunsmithing — ground sear, filed trigger, mystery parts
↓ Negotiate On These
- Heavy holster wear or finish loss — cosmetic only, knock 10–20% off price
- Aftermarket trigger or sights installed — verify legality and quality
- Worn recoil spring — $10–15 part, deduct from price
- Grimy interior — detail strip and clean before evaluating further
Frame & Slide
Barrel & Bore
Function Check
Feed System & Magazines
Legal & Serial Number
⚠ Immediate Walk-Away Conditions
- Cylinder timing is off — any chamber that doesn't align with the barrel
- Cracked frame, barrel, or cylinder
- Obliterated serial number
- Forcing cone erosion that catches your fingernail — leading and gas cutting damage
- Cylinder won't lock up solid on any chamber
- Hammer or trigger won't return fully in either action mode
↓ Negotiate On These
- Finish wear, holster marks — cosmetic only
- Slight cylinder end-shake — sometimes correctable by a gunsmith
- Grips worn or replaced — cheap to fix
- Cylinder gap slightly wide — have a gunsmith verify if close to .010"
Cylinder Timing & Lockup
Barrel & Forcing Cone
Action & Trigger
Frame & Legal
⚠ Immediate Walk-Away Conditions
- Obliterated or altered serial number on lower receiver
- Any sign of auto-conversion: third pin hole, M16 BCG in a semi-auto lower without proper documentation
- Cracked upper or lower receiver — especially around the pivot pin area
- Severely eroded barrel crown — cannot be unseen, affects accuracy fundamentally
- Carrier key not staked — screws will back out under fire
- Evidence of amateur trigger job: filed sear, bent disconnector, mystery spring
↓ Negotiate On These
- Upper/lower fit wobble — pin trick or accu-wedge is a $5 fix
- Budget BCG — verify staking, price it into your offer
- Worn finish on handguard or barrel — cosmetic
- Missing dust cover or forward assist — minor, cheap parts
Upper & Lower Receiver
Barrel & Gas System
Bolt Carrier Group
Trigger Group & Controls
HexCore Tool
Check Build Legality by State
Use the HexCore Build Legality Scanner to verify barrel length, overall length, and suppressor compliance by state — covers AWB rules, mag limits, and SBR thresholds across all 50 states.
Open Build Legality Scanner →Legal & NFA Compliance
⚠ Immediate Walk-Away Conditions
- Obliterated serial number
- Cracked stock at action screws or wrist — structural failure under recoil
- Visible pitting or erosion in the bore throat — accuracy is gone
- Bolt won't close on a go-gauge (headspace issue) — have a gunsmith check if in doubt
- Safety won't engage or hold — function before anything else
- Signs of relined or rebarreled chamber without documentation
↓ Negotiate On These
- Stock finish wear, handling marks — cosmetic, no structural impact
- Factory trigger that breaks rough — aftermarket triggers are $75–200
- Scope not included or cheap glass — price out a replacement
- Surface rust on exterior metal — can be addressed, check if it's deep
Barrel & Bore
Bolt & Action
Stock & Bedding
Trigger & Controls
⚠ Immediate Walk-Away Conditions
- Any dent or bulge in the barrel — catastrophic failure risk
- Obliterated serial number
- Barrel shorter than 18" without documented SBS NFA registration
- Cracked receiver — especially around the hinge on break-actions
- Loose barrel-to-receiver fit on a break-action — headspace issue
- Firing pin protrudes with action closed — slam-fire risk
↓ Negotiate On These
- Stock finish wear or field scratches — cosmetic
- Missing choke tubes — check availability and price
- Heavy carbon buildup — clean it before final judgment
- Worn blueing — cosmetic but can indicate age/round count
Barrel & Chamber
Action & Function
Stock & Controls
Legal & NFA Compliance
Legal Disclaimer
This checklist is a general reference guide for educational purposes only. It does not substitute for a professional gunsmith inspection. HexCore Mounts LLC makes no warranty regarding the accuracy or completeness of this information. Always verify firearm condition with a qualified gunsmith before purchase. HexCore Mounts LLC is not responsible for any purchasing decisions made in reliance on this checklist. Some inspection items — particularly headspace and NFA compliance — require professional verification.
