FN 509

easy
Shop tier 2
high confidence
Pistol
striker fired
polymer frame
ambidextrous
duty pistol

field strip ~1 min · reassembly ~2 min · detail strip ~20 min

Before you begin Verify this firearm is unloaded. Remove the magazine or empty the cylinder or tube, lock the action open, and check the chamber both by sight and by touch. Keep the muzzle in a safe direction and remove all live ammunition from your work area.

FN Herstal limits owner disassembly The maker's own procedure goes as far as: Field strip only: slide, recoil spring assembly and barrel off the frame (striker released); manual also covers magazine and backstrap changes.. FN says the field strip is enough for thorough cleaning and that disassembly beyond the manual's instructions should only be done by a qualified armorer. (FN 509 Owner's Manual (66-100498 R2, 2603) — FN America, LLC, p. 39 fnamerica.com [4])

Specifications

Manufacturer: FN Herstal
Origin: United States
Category: Pistol
Action: Striker-fired, short recoil
Calibers: 9x19mm Parabellum
Capacity: 17+1 with the standard magazine
Production: 2017–present (in-production)
Also known as: FN 509 Tactical, FN 509 Compact, FN 509 MRD

Model-specific safety

Trigger press required to disassemble This design requires pressing the trigger as part of the takedown. That makes verifying an empty chamber non-negotiable. Check it twice, keep the muzzle in a safe direction, and never take a shortcut on this step.

This pistol requires a trigger press to field strip — the striker has to be released before the slide will come off. Verify the chamber is empty, verify it again, and point the muzzle somewhere a round would not matter before your finger goes near the trigger.
The recoil spring assembly is under tension when the slide is off.
Controls are fully ambidextrous. Confirm the slide stop on both sides is clear of your grip during the function check.

If it will not go back together

Common ways this firearm resists reassembly, and what is actually wrong. Forcing a part that will not seat is how firearms get damaged.

The slide will not pull forward off the frame.

Why The striker has not been released, or was inadvertently recocked.

Fix With the chamber verified empty and the muzzle in a safe direction, keep the rear of the slide and frame aligned and press the trigger to release the striker, then pull the slide forward.
The barrel will not come out of the slide.

Why It is being lifted straight out. The 509 barrel clears the extractor first.

Fix Grasp the barrel by its lug, lift it up and around the extractor, then slide it rearward out of the slide.

Under spring tension

Recoil spring assembly

Easily lost parts

Takedown lever

Tools

No tools required for the field strip.

Shop difficulty

Shop tier 2 Tier 2 — moderate among pistols, for the full job: strip to the parts that get coated and put it back together working. 59 line items in FN's standard-model list (some are day/night, backstrap and magazine variants); FN marks the unlock-block pin, fire-control pin, extractor pin and sights as replace-after-removal, restricts detail work to an armorer, and the manual-safety fire control carries a ball detent and spring. More parts and more traps than a Glock.

Parts: 59 numbered parts (FN 509 standard model, full-size frame, NMS and MS fire control; the parts list on this page (schematic pp. 58-59, list pp. 60-61); MRD/Tactical slide and Midsize/Compact lists omitted; 59 pieces), from FN 509 Owner's Manual — FN America, LLC, p. 60–61 fnamerica.wpenginepowered.com [1].

Bench time: about 25 min to strip, 35 min to rebuild (estimate). Estimate for an experienced tech with the right tools, detail strip to coatable parts (slide internals, frame pins, trigger group, sights) and rebuild to a function-checked gun; scale used across pistols: Glock-pattern 15/20 min, other strikers 20-30/25-40, DA/SA hammer guns 30-35/45-50, Hi-Power, Colt 1903 and Mark 23 40-45/60-75.

Small parts: 8 pins, 13 springs, 2 detents or plungers (counted from the manufacturer's parts list (one per key number unless a quantity is given))

What comes off for coating

Slide: slide end cap, striker, springs, guide and stop pin, striker block and spring, extractor, pin and spring, front sight, rear sight
Barrel: barrel, recoil spring assembly
Frame: backstrap and pin, unlock block retaining pin and unlock block, trigger pin and trigger assembly, slide stop lever and spring, take down lever, fire control pin and fire control assembly (sear, carrier, springs, pins; ball detent on MS), magazine release and spring — punch set, frame fixture (optional)

Special tools

Replacement pins kit (unlock block retaining pin, fire control pin, extractor pin) — FN marks these replace-after-removal
Frame fixture / support block (e.g. Apex FN disassembly fixture) — Driving the forward unlock-block pin without damage

Known pain points

Several pins and the sights are single-use per FN: the unlock block retaining pin, fire control pin, extractor pin and front/rear sights carry 'replacement recommended after removal', so a shop needs new ones on hand. (reassembly)
Source: FN 509 Owner's Manual (66-100498 R2, 2603) — FN America, LLC fnamerica.com [4] — “* Replacement recommended after removal”
FN restricts disassembly past the field strip to a qualified armorer. (both)
Source: FN 509 Owner's Manual (66-100498 R2, 2603) — FN America, LLC fnamerica.com [4] — “Disassembly beyond the instructions provided in this manual should only be carried out by a qualified armorer.”
Manual-safety models carry a ball bearing and detent spring in the fire control, a captive detent that can fly. (both)
Source: FN 509 Owner's Manual (66-100498 R2, 2603) — FN America, LLC fnamerica.com [4] — “411*** Spring, Detent”

See also 2 documented reassembly problems and their fixes.

Fit or check on rebuild

Install new pins and sights — FN marks the pins and sights 'replacement recommended after removal'
Source: FN 509 Owner's Manual (66-100498 R2, 2603) — FN America, LLC fnamerica.com [4] — “* Replacement recommended after removal”
Sight position / re-zero — Drift or pressed sights moved for coating shift point of impact unless witness-marked and returned to the same spot
Full function check (trigger reset, safeties, slide lock-back, drop of striker/hammer only on trigger) — Standard after any fire-control strip; confirms springs and sears went back correctly

This is Pew-Takedown's rating, not the manufacturer's. How tiers are rated. Forum reports are owners' experience, not specifications.

Procedures

Clear and Make Safe

Clear & Make Safe

Point the muzzle in a safe direction and keep your finger off the trigger.
Press the magazine release and remove the magazine.
Removed at this step: Magazine
Retract the slide fully to eject any chambered round and lock it open.
Visually inspect the chamber and magazine well, then physically feel the chamber to confirm it is empty.
WarningLook and feel. Both, every time.
Remove all live ammunition from the work area.

Field Strip

Complete the Clear and Make Safe procedure and confirm the chamber is empty. Wear eye protection.
Retract the slide and lock it in its rearward position using the slide stop.
Remove the magazine and rotate the takedown lever downward.
Release the slide stop and ease the slide forward.
Keeping the rear of the slide and the rear of the frame in alignment, point the muzzle in a safe direction and press the trigger to release the striker. The slide moves forward slightly as it releases.
WarningThis pistol requires a trigger press to field strip — the striker has to be released before the slide will come off. Verify the chamber is empty, verify it again, and point the muzzle somewhere a round would not matter before your finger goes near the trigger.
TipFN's manual states the pistol must be completely unloaded to perform this step, and warns that failure to follow it could result in serious injury or death.
Pull the slide forward and away from the frame.
TipIf the striker was inadvertently recocked, go back and release it again before trying.
Removed at this step: Slide
Hold the slide upside down, grasp the small spring of the recoil spring assembly, and lift the assembly up and out of the slide.
Removed at this step: Recoil spring assembly
Remove the thread protector or muzzle device if the pistol has a threaded barrel.
Grasp the barrel by its lug, lift it up and around the extractor, and slide it rearward out of the slide.
TipUp and around the extractor, then rearward. It does not lift straight out.
Removed at this step: Barrel
Stop here. FN states this level of disassembly is sufficient for a thorough cleaning.

Reassembly

Fit the barrel back into the slide, reversing the lift-and-around-the-extractor motion.
Install the thread protector or muzzle device if the pistol has a threaded barrel.
Place the large end of the recoil spring assembly against the recess in the front of the slide, compress it, and slide the back of the recoil spring guide onto the recess until it is centred on the front of the barrel lug.
Guide the slide and barrel assembly onto the frame and pull the slide to its rearmost position, locking it with the slide stop.
Rotate the takedown lever upward, locking the frame and slide together.
Release the slide and let it travel forward, then test the slide stop, trigger, magazine release and manual safety if fitted.

Patent drawings

not under copyright

Drawings from US patents on this design. A patent shows the invention as the inventor filed it; the firearm that shipped can differ in detail, and later production often does. Use them to see how the parts relate, not as a parts reference or a procedure. Per the USPTO, the text and drawings of a patent are typically not subject to copyright; each patent here was checked for a copyright notice.

US Patent 10,352,654 — Firearm with interchangeable sighting device system

Olivier Holger Costet, Luke Randel Howlett · assigned to FN Herstal SA · filed 2018-05-02 · granted 2019-07-16. Full patent (USPTO)

The optics-ready (MRD) slide of the FN 509: the stepped cut in the top of the slide, the interchangeable adaptor plate and its retaining spring, and how a red-dot sight bolts onto it.

Why this is the FN 509’s patent: listed on the maker’s patent-marking page — FN Patents | FN® Firearms — FN America, LLC fnamerica.com [8]: “Pursuant to 35 U.S.C. § 287(a), FN hereby provides notice that the FN products identified below are protected by the corresponding patents listed. ... FN 509® Series* U.S. Patent No. 10,352,654 *Excludes the following products: non optics-ready FN 509, FN 509 Midsize and FN 509 Compact.”

**US Patent 10,352,654, Sheet 1 of 6 — FIG. 1** The patent: “FIG. 1 is a left side view the auto-loading pistol of FIG. 1, according to an aspect of the disclosure;” Drawn for the patent, as filed; the production firearm may differ in detail. US Patent 10,352,654 — Firearm with interchangeable sighting device system, Sheet 1 of 6 — United States Patent and Trademark Office. Source. US patent drawing, not subject to copyright.

**US Patent 10,352,654, Sheet 2 of 6 — FIG. 2, FIG. 3** The patent: “FIG. 2 is an upper left perspective view of the slide shown in FIG. 1 with the optical sight removed to show the first portion and the second portion of the slide with the adaptor plate positioned in the second portion, according to an aspect of the disclosure; FIG. 3 is an upper left perspective view of the slide shown in FIG. 2 with the adaptor plate removed to show the spring retained by a feature formed in the second portion, according to an aspect of the disclosure;” Drawn for the patent, as filed; the production firearm may differ in detail. US Patent 10,352,654 — Firearm with interchangeable sighting device system, Sheet 2 of 6 — United States Patent and Trademark Office. Source. US patent drawing, not subject to copyright.

Torque specifications

Use a calibrated torque driverValues are the manufacturer's, shown in the unit it gives first; conversions are calculated and rounded. Tighten to the stated value — not "until it feels right" — and follow any sequence noted.

Fastener	Torque	Sequence, notes and the source's words	Where it comes from
Optic / slide-cap mounting screws (T10 Torx) through the MRD plate FN Optics Mounting System ("FN's patented Low Profile Optics Mounting System, U.S. Patent No. 10,352,654"), the MRD system the FN 509 owner's manual describes in section 11 with the same plates (501-5	22 in-lb 2.5 N·m · 1.8 ft-lb	Remove lubrication from screws and holes; o-ring in slide recess; MRD plate over o-ring; optic or slide cap (with MRD insert if required); start both screws; tighten with finger pressure with the T10 wrench. Threadlocker: "DO NOT USE THREADLOCKER." (self-locking system) “Start both mounting screws and tighten them down clock-wise with finger pressure with the provided T10 Torx wrench. (Recommended Torque spec: 22 in-lbs)”	Quick Setup & Reference Guide: FN Optics Mounting System (2603) — FN America, LLC, PDF p. 1, step 9 fnamerica.com [3]

Fastener

Torque

Sequence, notes and the source's words

Where it comes from

Optic / slide-cap mounting screws (T10 Torx) through the MRD plate
FN Optics Mounting System ("FN's patented Low Profile Optics Mounting System, U.S. Patent No. 10,352,654"), the MRD system the FN 509 owner's manual describes in section 11 with the same plates (501-5

22 in-lb
2.5 N·m · 1.8 ft-lb

Remove lubrication from screws and holes; o-ring in slide recess; MRD plate over o-ring; optic or slide cap (with MRD insert if required); start both screws; tighten with finger pressure with the T10 wrench.

Threadlocker: "DO NOT USE THREADLOCKER." (self-locking system)

“Start both mounting screws and tighten them down clock-wise with finger pressure with the provided T10 Torx wrench. (Recommended Torque spec: 22 in-lbs)”

Quick Setup & Reference Guide: FN Optics Mounting System (2603) — FN America, LLC, PDF p. 1, step 9 fnamerica.com [3]

Notes: The manufacturer's documents give no torque value. They say: "Start both mounting screws and tighten them down clock-wise with finger pressure with the provided T10 Torx wrench." (FN 509 Owner's Manual (66-100498 R2, 2603), PDF p. 25 (section 11, optic installation step 9)) "Thread the suppressor or muzzle device on to the barrel and tighten it following the manufacturers recommendations." (FN 509 Owner's Manual (66-100498 R2, 2603), PDF p. 27)

Reported by other sources — not the manufacturer

Not a manufacturer specificationThese values come from the people and publications named beside each one, not from FN Herstal, and where they differ from the manufacturer's values above, the manufacturer wins. They are recorded with who said them and their exact words so you can judge them — not as a recommendation. Confirm any of them with the manufacturer or a licensed gunsmith before you put a wrench on your firearm; a wrong value can crack a stock, strip a thread or loosen a muzzle device.

Fastener	Torque	Who says so, and their words	Where it comes from
Optic plate to slide screws (6-40 x 5/8 T10) FN 509 series (optics-ready) with Forward Controls Design OPF-FN509T, ACRO plate	13–15 in-lb 1.5–1.7 N·m · 1.1–1.2 ft-lb	Reported by Forward Controls Design Secondary — a parts or tool maker, or a gunsmithing publisher “Torque value for the plate to slide 6-40 x 5/8 T10 screws is 13 to 15 in lbs.”	OPF-FN509T, ACRO (product page) — Forward Controls Design forwardcontrolsdesign.com [2]
Aimpoint ACRO P1/P2 mounting screw FN 509 series with FCD OPF-FN509T, ACRO plate, Aimpoint ACRO P1/P2	26 in-lb 2.9 N·m · 2.2 ft-lb	Reported by Forward Controls Design Secondary — a parts or tool maker, or a gunsmithing publisher “Torque value for Aimpoint P1/P2 is 26 in lbs, and 20 in lbs for Steiner MPS.”	OPF-FN509T, ACRO (product page) — Forward Controls Design forwardcontrolsdesign.com [2]
Steiner MPS mounting screw FN 509 series with FCD OPF-FN509T, ACRO plate, Steiner MPS	20 in-lb 2.3 N·m · 1.7 ft-lb	Reported by Forward Controls Design Secondary — a parts or tool maker, or a gunsmithing publisher “Torque value for Aimpoint P1/P2 is 26 in lbs, and 20 in lbs for Steiner MPS.”	OPF-FN509T, ACRO (product page) — Forward Controls Design forwardcontrolsdesign.com [2]
Red-dot optic mounting screws (6-32 flat head, supplied) into EGW rear-dovetail sight mount FN 509 (listed as fitting EGW's Sig #8-cut dovetail mount; EGW lists FN 509 Tactical as NOT fitting) with the EGW 'Trijicon RMR / SRO, Holosun 407c / 507c Mount for Sig Sauer P220, P226, P229, P320' (	15 in-lb 1.7 N·m · 1.2 ft-lb	Reported by Evolution Gun Works (EGW) Secondary — a parts or tool maker, or a gunsmithing publisher Remove the rear sight, install the EGW mount in the dovetail, tighten the set screw if applicable, place the optic on the mount, then apply blue Loctite and torque the optic screws. Threadlocker: Blue Loctite on the provided mounting screws (EGW instructions) “Torque mounting screws to 15in/lbs”	Trijicon RMR / SRO, Holosun 407c / 507c Mount for Sig Sauer P220, P226, P229, P320 (EGW product page, installation instructions section) — Evolution Gun Works (EGW) egwguns.com [6]
Red-dot optic mounting screws (supplied) into EGW rear-dovetail sight mount (Docter/Venom/Viper/FastFire footprint) FN 509 (listed as fitting EGW's Sig #8-cut dovetail mount; EGW lists FN 509 Tactical as NOT fitting) with the EGW 'SIG Sauer P220 P226 P229 P320 Red Dot Mount \| Fits Vortex Venom, Viper & Burris FastF	15 in-lb 1.7 N·m · 1.2 ft-lb	Reported by Evolution Gun Works (EGW) Secondary — a parts or tool maker, or a gunsmithing publisher Remove the rear sight, install the EGW mount in the dovetail, tighten the set screw if applicable, place the optic on the mount, then apply blue Loctite and torque the optic screws. Threadlocker: Blue Loctite on the provided mounting screws (EGW instructions) “Torque mounting screws to 15 in/lbs”	SIG Sauer P220 P226 P229 P320 Red Dot Mount \| Fits Vortex Venom, Viper & Burris FastFire \| EGW (EGW product page, installation instructions section) — Evolution Gun Works (EGW) egwguns.com [7]

Materials and factory finish

As stated by FN Herstal. Prep, masking and cure depend on these; a polymer or aluminium part, a nitrided or anodised finish, and a blued steel part are each a different job. Variants with other finishes may exist — check the maker's page for the exact SKU on the bench.

Component	Material	Factory finish	Where it comes from
Barrel FN 509 (standard, 4in), e.g. 66-100002 FN 509 NMS BLK/BLK	stainless steel	—	FN 509® — product page (Specs / Primary Features) — FN America, LLC fnamerica.com [5] “BARREL … Cold hammer-forged stainless steel”
Frame FN 509 (standard, 4in), e.g. 66-100002 FN 509 NMS BLK/BLK	Polymer	—	FN 509® — product page (Specs / Primary Features) — FN America, LLC fnamerica.com [5] “FRAME … Polymer construction with replaceable steel frame/slide rails”
Magazine FN 509 (standard, 4in), e.g. 66-100002 FN 509 NMS BLK/BLK	polymer	black	FN 509® — product page (Specs / Primary Features) — FN America, LLC fnamerica.com [5] “MAGAZINE … High visibility, low-friction follower; polymer base with black finish”

Parts list

Transcribed from the manufacturer's parts list (FN 509 Owner's Manual — FN America, LLC, p. 60–61 fnamerica.wpenginepowered.com [1]) — FN 509 standard model (full-size frame; NMS and MS fire control). Omitted: 509 Tactical/MRD slide assemblies list (pp.64-65) and 509 series Midsize/Compact frame & magazine list (pp.68-69). Schematic pp.58-59.. Key numbers refer to the exploded view in that document.

59 parts

Key	Part	Qty
101	Unlock Block	1
102	Pin, Unlock Block Retaining Replacement recommended after removal	1
103	Trigger Assembly	1
104	Lever, Slide Stop	1
105	Spring, Slide Stop	1
106	Pin, Trigger	1
107	Lever, Take Down	1
108	Pin, Fire Control Replacement recommended after removal	1
109	Release, Magazine	1
110	Spring, Magazine Catch	1
111F-A	Backstrap, Small, Black	1
111F-B	Backstrap, Medium, Black	1
111F-C	Backstrap, Large, Black	1
112	Pin, Backstrap Retaining	1
200-A	Slide Assembly, FN 509, Black, DS	1
200-B	Slide Assembly, FN 509, Black, NS	1
201	Slide, FN 509, 9mm, Black	1
202	Barrel, 4.02"	1
203	Recoil Spring Assembly	1
204-A	Sight, Front, Day Replacement recommended after removal	1
204-B	Sight, Front, Night Replacement recommended after removal	1
205-A	Sight, Rear, Day Replacement recommended after removal	1
205-B	Sight, Rear, Night Replacement recommended after removal	1
206	Extractor	1
207-A	Pin, Extractor Replacement recommended after removal	1
208	Spring, Extractor	1
209	Striker	1
210	Spring, Striker Return	1
211	Striker Spring Stop	1
212	Pin, Striker Spring Stop	1
213	Spring, Striker	1
214	Guide, Striker Spring	1
215	Slide End Cap	1
216	Block, Striker	1
217	Spring, Block	1
300F-A	Magazine Assembly, 17 Rd, Black	1
300F-B	Magazine Assembly, 10 Rd, Black	1
301	Follower, 9mm, Orange	1
302F	Spring, Magazine	1
303	Catch, Magazine Floorplate	1
304	Floorplate, Magazine, Black	1
305F-A	Tube, 509F Magazine, 17 Rd	1
305F-B	Tube, 509F Magazine, 10 Rd	1
400-A	Fire Control Assembly, 509, NMS	1
400-B	Fire Control Assembly, 509, MS	1
401	Housing, Left	1
402	Housing, Right	1
403	Sear	1
404	Carrier, Sear	1
405	Cam, Disconnect	1
406	Spring, Disconnect	1
407	Spring, Sear	1
408	Spring, Carrier	1
409	Pin, Carrier	1
410	Pin, Carrier Spring	1
411	Spring, Detent Manual safety model only	1
412	Bearing, Ball Manual safety model only	1
413	Clip, Retaining Non-manual safety model only	1
414	Overmold, Manual Safety Manual safety model only	1

Function check

After every reassemblyPerform these checks on a verified-unloaded firearm. If any check fails, the firearm is not safe to fire — stop and see a licensed gunsmith.

Verify the pistol is unloaded with no magazine inserted before each check.
Rack the slide and press the trigger. The striker should release cleanly.
Hold the trigger to the rear, rack the slide, then release slowly and confirm the reset.
Press the trigger again to confirm the striker releases.
Confirm the slide locks open on an empty magazine and the magazine drops free.

Maintenance

Lubrication points

Frame rails where the slide rides
Barrel hood and locking lug
Outside of the barrel at the muzzle end
Rear barrel lug where the recoil spring assembly bears

Cleaning notes

Light lubrication only — a thin film on the rails and barrel. Keep the striker channel dry and free of solvent, since oil there collects fouling and causes light strikes.

Suggested inspection interval: roughly every 5000 rounds. This is a general guideline, not a manufacturer specification.

Wear parts to inspect

Recoil spring assembly · Extractor · Striker spring

Common issues

Symptom	Likely cause	What to do
Slide locks back with rounds remaining	Support-hand thumb riding the ambidextrous slide stop	Adjust grip so the thumb rides clear of the lever.

Also covers

The procedures above are reported to apply to: FN 509 Tactical · FN 509 Compact · FN 509 LS Edge. Verify against the manual for your specific model.

Similar manual of arms

Sourcing

Confidence: high — Cross-checked against a primary source such as the manufacturer's manual or an issuing military technical manual.
Verification: Checked against the manufacturer manual
Last updated: 2026-10-29

References

Every source this page draws on, with its web address so you can read it yourself. Numbers in brackets elsewhere on the page point here.

[1] FN 509 Owner's Manual — FN America, LLC manufacturer manual primary source
https://fnamerica.wpenginepowered.com/wp-content/uploads/2026/03/2603_FN_509-OM_66-100498_R2.pdf (checked 2026-09-15)
[2] OPF-FN509T, ACRO (product page) — Forward Controls Design website secondary source
https://www.forwardcontrolsdesign.com/OPF-FN509T-ACRO_p_517.html (checked 2026-09-27)
[3] Quick Setup & Reference Guide: FN Optics Mounting System (2603) — FN America, LLC manufacturer manual primary source
https://fnamerica.com/wp-content/uploads/2026/03/2603_Quick_Setup_Reference_Guide_FN_OPTICS_MOUNTING_final.pdf (checked 2026-09-27)
[4] FN 509 Owner's Manual (66-100498 R2, 2603) — FN America, LLC manufacturer manual primary source
https://fnamerica.com/wp-content/uploads/2026/03/2603_FN_509-OM_66-100498_R2.pdf (checked 2026-09-27)
[5] FN 509® — product page (Specs / Primary Features) — FN America, LLC website primary source
https://fnamerica.com/products/pistols/fn-509/ (checked 2026-10-03)
[6] Trijicon RMR / SRO, Holosun 407c / 507c Mount for Sig Sauer P220, P226, P229, P320 (EGW product page, installation instructions section) — Evolution Gun Works (EGW) website secondary source
https://egwguns.com/trijicon-rmr-sro-holosun-407c-507c-mount-for-sig-sauer-p220-p226-p229-p320 (checked 2026-10-11)
[7] SIG Sauer P220 P226 P229 P320 Red Dot Mount | Fits Vortex Venom, Viper & Burris FastFire | EGW (EGW product page, installation instructions section) — Evolution Gun Works (EGW) website secondary source
https://egwguns.com/vortex-viper-venom-sig-sauer-p220-p226-p229-p320-sight-mount-fits-burris-fastfire-and-docter (checked 2026-10-11)
[8] FN Patents | FN® Firearms — FN America, LLC website primary source
https://fnamerica.com/fn-patents/ (checked 2026-10-13)

Notes: Cleanup on 2026-09-15: when this entry's trigger-press flag was corrected, the stale text asserting the opposite was left behind. The rendered page carried the new warning and the old contradicting one together, and in some cases a 'no trigger pull takedown' tag in the header. Removed. This was caught by screenshotting the built page rather than by any test, which is why a test now covers it. CORRECTED on 2026-09-15 against the factory manual. The entry recorded triggerPullRequiredToDisassemble as false. The FN 509 requires the striker to be released with the trigger before the slide will come off the frame, and FN's manual carries an explicit warning that the pistol must be completely unloaded for that step or serious injury or death could result. That makes five pistols in this pass found carrying the flag backwards. Also corrected the barrel removal, which goes up and around the extractor then rearward rather than lifting straight out. Rated medium pending confirmation against a specific variant manual; the 509 line includes Tactical, Compact, MRD, and LS Edge models differing in slide, barrel, and optic mounting.

Found something wrong? Corrections are the most valuable contribution to this project. Open an issue with the model, the step, and a source.