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FN Five-seveN
- easy
- Shop tier 2
- high confidence
- Pistol
- delayed blowback
- high velocity
- polymer frame
- high capacity
field strip ~1 min · reassembly ~2 min · detail strip ~20 min
Specifications
- Manufacturer
- FN Herstal
- Origin
- Belgium
- Category
- Pistol
- Action
- Delayed blowback
- Calibers
- 5.7x28mm
- Capacity
- 20+1
- Production
- 1998–present (in-production)
- Also known as
- FN 5.7, Five-seveN MK2
Model-specific safety
- The Five-seveN uses a delayed-blowback action rather than a locked-breech tilting barrel, so the barrel does not tilt and the takedown feel differs from a conventional service pistol.
- 5.7x28mm is a high-velocity small-calibre cartridge. Treat the bore and chamber accordingly and do not substitute ammunition types casually.
- The recoil spring assembly is under tension when the slide is off.
- The polymer frame and slide cover make the pistol very light for its size — the slide has less mass than its dimensions suggest.
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 go back onto the frame.
Why One of FN's three preconditions is unmet: the takedown lever must be rearward, the frame must hold no magazine, and the hammer must be cocked.
Fix Check all three, then hold the slide parallel above the frame and align its rear with the front of the frame's rear guide rails.
Under spring tension
- Recoil spring assembly
Easily lost parts
Takedown lever · Recoil spring assembly
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. No parts count found. A hammer-fired delayed-blowback pistol with a polymer-clad steel slide; FN limits all work past the field strip to an armorer or the FN Service Center, and even the owner-level magazine catch swap needs the trigger held back while the spring is pulled and re-seated in a set orientation. Rated Tier 2 on design and FN's restrictions, not on counted parts.
No sourced part count yet.
Bench time: about 30 min to strip, 40 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. No parts list; hammer-fired with polymer-clad slide;
What comes off for coating
- Slide: firing pin and spring, extractor, sights
- Barrel: barrel, recoil spring assembly
- Frame: magazine catch and spring, hammer and trigger group, takedown lever, slide stop — 3/32 in. drift punch
Special tools
- 3/32 in. drift punch — Magazine catch spring
Known pain points
- FN limits disassembly beyond the field strip to a qualified armorer or the FN Service Center. (both)
Source: FN Five-seveN Series Owner's Manual (MRD edition, FN010 2204) — FN America, LLC fnamerica.com [2] — “Further disassembly should only be carried out by a qualified armorer or by the FN Service Center.” - The magazine catch spring can only be pulled with the trigger held to the rear and a 3/32 in. punch. (disassembly)
Source: FN Five-seveN Series Owner's Manual (MRD edition, FN010 2204) — FN America, LLC fnamerica.com [2] — “While pulling the trigger and using a 3/32” drift punch, pull the magazine catch spring out of its housing inside the frame and then remove it.” - The magazine catch spring goes back in one orientation only, again with the trigger held back. (reassembly)
Source: FN Five-seveN Series Owner's Manual (MRD edition, FN010 2204) — FN America, LLC fnamerica.com [2] — “While pulling the trigger, reinstall the magazine catch spring, oriented as shown, into its housing inside the frame.”
See also 1 documented reassembly problem and their fixes.
Fit or check on rebuild
- Magazine catch spring orientation — The spring goes back in one orientation with the trigger held to the rear
Source: FN Five-seveN Series Owner's Manual (MRD edition, FN010 2204) — FN America, LLC fnamerica.com [2] — “While pulling the trigger, reinstall the magazine catch spring, oriented as shown, into its housing inside the frame.” - 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
Field Strip- Complete the Clear and Make Safe procedure. After the safety checks, do NOT insert a magazine.
- Hold the pistol in your right hand. With the palm of your left hand, push the slide about 0.5 cm (0.25 in) rearwards and hold it there.TipA quarter of an inch. Not locked back.
- At the same time, with your left thumb, push the take down lever completely rearwards and hold it there.TipRearwards, not rotated down. This is a sliding lever, not a rotating one.
- Release the slide so that it returns forward.
- With your right thumb, push forwards on the rear end of the slide to disengage the complete slide assembly from the frame, then lift the slide assembly up and off the frame.TipUp and off, not forward off the front.Removed at this step:
Slide assembly - With the slide assembly held upside down, disengage the rear end of the barrel and take the barrel out of the slide.Removed at this step:
Barrel - Stop here. FN states this level of disassembly is sufficient for thorough cleaning, and that anything further should be done only by an authorised armorer or by FN Herstal or FN America.
Reassembly
Reassembly- Check every component is perfectly clean before you start.
- Insert the muzzle of the barrel into the barrel opening at the front of the slide.
- Push the barrel slightly forwards against the force of the return spring, then fit the rear end of the barrel into position in the slide.
- Before going further, check three things: the take down lever is at the rear position, the frame holds no magazine, and the hammer is cocked.TipAll three. Any one of them wrong and the slide will not go back on.
- Holding the slide assembly parallel above the frame, align the rear end of the slide assembly with the front end of the frame's rear guide rails, then seat it.
- Return the take down lever forward, cycle the slide, and perform the function check.
Torque specifications
| Fastener | Torque | Sequence, notes and the source's words | Where it comes from |
|---|---|---|---|
| Optic securing screws (T10 Torx), with interface plate if applicable FN Five-seveN MRD (optics-ready slide) |
22 in-lb 2.5 N·m · 1.8 ft-lb |
Remove cover plate; clean mounting surface; select securing screws and interface per chart; remove lubrication from screws and holes; position optic (with interface if required); add threadlocker to both screws and tighten clockwise with the T10 wrench. Threadlocker: "Add a medium-strength threadlocker, such as Loctite Blue 242® to both securing screws" and follow its cure time “The recommended torque is 22 in-lbs.” |
FN Five-seveN Series Owner's Manual (MRD edition, FN010 2204) — FN America, LLC, PDF p. 21 (5.1 Installing an optic) fnamerica.com [2] |
| Cover plate securing screws (T10 Torx) FN Five-seveN MRD (optics-ready slide) |
22 in-lb 2.5 N·m · 1.8 ft-lb |
“The recommended torque is 22 in-lbs.” |
FN Five-seveN Series Owner's Manual (MRD edition, FN010 2204) — FN America, LLC, PDF p. 22 (5.2 Removing an optic, cover fnamerica.com [2] |
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 |
|---|---|---|---|
| Slide FN Five-seveN (standard, 4.8in) | steel | — | FN Five-seveN® — product page (Specs / Primary Features) — FN America, LLC fnamerica.com [3] “SLIDE … One-piece machined steel slide … Polymer cover” |
| Barrel FN Five-seveN (standard, 4.8in) | stainless steel | — | FN Five-seveN® — product page (Specs / Primary Features) — FN America, LLC fnamerica.com [3] “BARREL … Cold hammer-forged stainless steel … Chrome-lined chamber and bore” |
| Frame FN Five-seveN (standard, 4.8in) | Polymer | — | FN Five-seveN® — product page (Specs / Primary Features) — FN America, LLC fnamerica.com [3] “FRAME … Polymer construction” |
| Magazine FN Five-seveN (standard, 4.8in) | Polymer | — | FN Five-seveN® — product page (Specs / Primary Features) — FN America, LLC fnamerica.com [3] “MAGAZINE … Polymer body … Low-friction follower … Polymer base” |
Function check
- 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 or firing pin 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 · Magazine springs and followers
Common issues
| Symptom | Likely cause | What to do |
|---|---|---|
| Takedown lever will not rotate | Slide not fully locked to the rear | Lock the slide fully open and try again. |
Also covers
The procedures above are reported to apply to: Five-seveN MK2 · Five-seveN MRD. 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 Five-seveN MK2 Owner's Manual — FN America, LLC manufacturer manual primary source
https://fnamerica.wpenginepowered.com/wp-content/uploads/2020/06/2005_Five-seveN_OM_05.20201_V2.pdf (checked 2026-09-15) - [2] FN Five-seveN Series Owner's Manual (MRD edition, FN010 2204) — FN America, LLC manufacturer manual primary source
https://fnamerica.com/wp-content/uploads/2022/07/FN010_2204_Five-seveN-MRD_Manual_web.pdf (checked 2026-09-27) - [3] FN Five-seveN® — product page (Specs / Primary Features) — FN America, LLC website primary source
https://fnamerica.com/products/pistols/fn-five-seven/ (checked 2026-10-03)
Notes: CORRECTED on 2026-09-15 against the factory manual. The entry was a generic striker-pistol template and wrong at almost every step. The Five-seveN's takedown lever slides rearwards rather than rotating down, the slide is moved only about 0.25 in rather than locked back, the slide lifts up and off rather than running forward off the frame, and FN documents no separate recoil spring removal at all. Reassembly now carries FN's three preconditions — lever rearward, no magazine, hammer cocked. Rated medium pending step-by-step confirmation against the factory manual. The important mechanical point — that this is a delayed-blowback design with a non-tilting barrel — is well established.