Sig Sauer M400 SDI Sentry, Semi-automatic Rifle, 223 Remington/5.56 NATO, 16″ Threaded Barrel, Black
Home » Shop » Sig Sauer M400 SDI Sentry, Semi-automatic Rifle, 223 Remington/5.56 NATO, 16″ Threaded Barrel, Black
Home » Shop » Sig Sauer M400 SDI Sentry, Semi-automatic Rifle, 223 Remington/5.56 NATO, 16″ Threaded Barrel, Black
Sale!
$1,899.99Original price was: $1,899.99.$1,749.99Current price is: $1,749.99.
🚚 Ships to your local FFL — order online, put your FFL dealer’s name and address in the Order notes box at checkout, and we coordinate the rest. Most firearms ship same or next business day. How buying a gun online works.
FREE SUPPRESSOR WITH THIS GUNBuy this firearm and get a free Outlier Backdraft Hunter 4″ suppressor, a $189 value. In stock now, while supplies last. How it works →
Sig Sauer M400 SDI Sentry is a semi-automatic AR rifle in .223 Remington/5.56 NATO with a 16" threaded barrel. It is for home defense, training and recreational shooters who want a red dot, a weapon light and a vertical foregrip already on the rifle.
Chambered in .223 Remington / 5.56 NATO
16" barrel with a threaded muzzle
30-round capacity, semi-auto action
ROMEO5 GENII red dot and FOXTROT-MSR light
Free-floating M-LOK forend with vertical foregrip
Fully ambidextrous controls
SKU: SGRM400-SDI-16B-R5FX · Mfr part #: RM400-SDI-16B-R5FX · UPC: 798681716128
The Sig Sauer M400 SDI Sentry is a semi-automatic AR rifle chambered in .223 Remington/5.56 NATO with a 16″ threaded barrel. It holds 30 rounds, wears a polymer stock and has a black anodized finish.
What sets the Sentry apart
The Sentry is built on the M400 SDI X platform and is set up as a complete rifle. It carries a ROMEO5 GENII red dot, a FOXTROT-MSR full size light and a vertical foregrip, so the main add-ons are already chosen. The forend is free-floating and uses M-LOK. Controls are fully ambidextrous, covering the safety, charging handle, and bolt catch and release. The trigger is the SIG 2-stage Matchlite Duo.
This rifle suits shooters who want one setup for home or personal defense, advanced training and recreational shooting. The red dot and light mean you can start working with it without picking out an optic or a light first. The ambidextrous controls help left-handed shooters and anyone who likes to train from both shoulders.
Good gear to pair with it includes extra 30-round magazines, a sling, M-LOK accessories for the forend, a muzzle device for the threaded barrel, and .223 Remington or 5.56 NATO ammunition. If you plan to add a muzzle device, confirm the thread fit with the maker before you order. A padded rifle case and a cleaning kit round out the setup.
Sig Sauer M400 SDI Sentry, Semi-automatic Rifle, 223 Remington/5.56 NATO, 16" Threaded Barrel, Black Specifications
Order online and we ship it to the licensed FFL dealer you choose near you — see how buying a gun online works. Western Sport has been a licensed FFL/SOT dealer since 2007, and everything we sell carries the full manufacturer warranty. Questions before you order? Send us a message.
Frequently Asked Questions
Q: What caliber is the Sig Sauer M400 SDI Sentry?
A: It is chambered in .223 Remington / 5.56 NATO. The action is semi-automatic.
Q: Does the M400 SDI Sentry have a threaded barrel?
A: Yes. The 16" barrel has a threaded muzzle for adding a muzzle device.
Q: How many rounds does the M400 SDI Sentry hold?
A: 30 rounds. That is the rated capacity of the magazine the rifle is set up for.
Q: Does the M400 SDI Sentry come with a red dot and light?
A: Yes. It is configured with a ROMEO5 GENII red dot and a FOXTROT-MSR full size light. A vertical foregrip is part of the setup too.
Q: Is the M400 SDI Sentry good for home defense?
A: Sig Sauer sets it up as an out-of-the-box rifle for home and personal defense. It has a red dot, a weapon light, a vertical foregrip, ambidextrous controls and a 2-stage trigger.
Warranty and Manufacturer
Covered by the Sig Sauer factory warranty; warranty terms come from Sig Sauer.
Reviews
There are no reviews yet.