Suppressors • $1,196
Surefire SOCOM556-RC2
- 5.56mm optimized
- SOCOM adopted
$1,196.00
Shop at Silencer Central
AR-15 Barrel & Overall Length Visualizer
Pick a barrel from 10.3 to 20 inches, hang a suppressor or a pinned muzzle device on it, collapse or extend the stock, and see the rifle drawn to scale against the 16 inch barrel line and the 26 inch overall length line, measured from the closed bolt face the way ATF measures it. Compare two builds side by side: a suppressed 11.5 inch SBR against a 14.5 inch barrel pinned past 16 inches, for example. The velocity view answers the other half of the question: what each barrel length does to 5.56 muzzle velocity, measured, and how far a load stays fast enough to expand.
Barrel, muzzle, and stock
16 in barrel line26 in overall lineMeasured from the closed bolt face; overall length with the stock where it is set, the 26 in line from full extension.
Configuration A
SBRStock position
- Barrel as measured
- 11.5 in4.5 in short the 16 in line
- Overall, stock position 6 of 6
- 30.03 in4.03 in over the 26 in line
- With threaded-on parts
- 35.81 insuppressor reaches 5.78 in past the muzzle
- Weight on the muzzle
- 20.9 oz
Configuration B
RifleStock position
- Barrel as measured
- 16.48 in0.48 in over the 16 in line
- Overall, stock position 6 of 6
- 35.01 in9.01 in over the 26 in line
- With threaded-on parts
- 38.81 insuppressor reaches 5.78 in past the muzzle
- Weight on the muzzle
- 20.9 oz
Barrel length
Closed bolt face to the muzzle, or to the end of a muzzle device that is pinned and welded, welded, or silver-soldered on. Under 16 inches is a short-barreled rifle.
Overall length
Muzzle to the rearmost point of the stock along the bore, with the stock extended. Under 26 inches is also a short-barreled rifle, though a stocked AR clears it with any barrel here.
What does not count
A suppressor that threads or locks on, and any flash hider or brake that is only threaded on. They change how long the rifle is in the safe, not how ATF measures it.
How the 14.5 inch pin-and-weld math works
A 14.5 inch barrel becomes a 16 inch barrel only through the device permanently attached to it, and the number that matters is how far that device reaches past the muzzle face, not its overall length. A SureFire SF3P-556 is 2.6 inches long, but the barrel's 0.62 inch thread tenon sits inside it, so it adds about 1.98 inches and a pinned 14.5 measures about 16.48 inches. The 2.7 inch WARCOMP-556 lands near 16.58 inches. A standard 1.75 inch A2 adds only about 1.13 inches, so a pinned 14.5 measures about 15.6 inches and stays an SBR; the extended A2 patterns (KAK's 2.06 inch A2 Extended, BCM's A2X) exist to push the same barrel past 16 inches. The visualizer applies these numbers when the device is marked pinned and welded; unpinned, the same device adds nothing to the measured barrel.
A suppressor that locks over the device or threads onto the muzzle is removable and does not count; only a permanently attached one would, and this visualizer does not model that case. The SureFire SOCOM cans lock over an SF3P or WARCOMP and add 3.0 to 3.8 inches past the front of that device, about 5 to 6 inches past the muzzle, the HUXWRX FLOW 556k adds 4.9 inches over its own Flash Hider-QD, and a direct-thread can like the Canik VOID-556 needs a bare muzzle, so it cannot go over a pinned device at all. The muzzle thread checker lists which devices and cans share your barrel's thread, and the suppressor mounting systems guide explains the Fast-Attach, Torque Lock, HUB, and direct-thread ecosystems those numbers come from.
Anything that measures under 16 inches with a shoulder stock is a short-barreled rifle. Since October 9, 2026, ATF does not enforce Form 1 or Form 4 approval for SBRs (what ATF's NFA change covers), a Form 5320.20 is still required before taking one across state lines, and state law still applies on top of that. The barrel length guide covers what each length gives up in velocity, the suppressor buying walkthrough covers the transfer, and the suppressor tracker shows current Form 4 processing times.
The suppressors, devices, and loads in the visualizer
Every can and mount is modeled to its published length and diameter, and every load in the velocity view is charted from measured muzzle velocities.
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Modeled suppressors and mounts
Suppressors • $1,472
SureFire SOCOM556-RC4
- 5.56 NATO
- Inconel hybrid
$1,472.00
Shop at KYGUNCO
Suppressors • $1,377
SureFire SOCOM556-MINI4
- 5.56 NATO / .223 Rem
- 5.5 in / 15 oz
$1,377.00
Shop at KYGUNCO
Suppressors • $1,054
Huxwrx Flow 556k
- 5.56mm rated
- Flow-through design
$1,054.00 Catalog
Shop at Primary Arms
Suppressors • $650
Canik VOID-556
- 5.56 NATO / 6mm ARC
- Welded 17-4 stainless
$650.00 Catalog
Shop at Silencer Central
Muzzle Devices • $152
SureFire SF3P Flash Hider
- Three-prong flash hider
- 1/2-28 host thread, .223/5.56
$152.00 Catalog
Shop at PSA
Muzzle Devices • $152
SureFire WARCOMP
- Open-tine flash hider and compensator
- 1/2-28 host thread, 5.56 NATO
$152.00
Shop at KYGUNCO
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Loads in the velocity view
Ammunition • $25.99
Hornady BLACK 5.56 NATO 75gr InterLock HD SBR
- 75 grain InterLock
- 5.56 NATO
$24.90$25.99Save 4%
Shop at KYGUNCO
Ammunition • $13.5
Hornady TAP 75gr
- 75 grain BTHP TAP
- .223 Remington
$13.50 Catalog
Shop at Ammunition Depot
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Frequently Asked Questions
▶How much velocity does a 10.3 or 11.5 inch barrel lose with 5.56?
Roughly 130 to 420 fps against a 16 inch barrel, depending on the load. In Lucky Gunner's chronograph test, Hornady BLACK 75gr InterLock HD SBR ran 2,291 fps from a 10.5 inch barrel and 2,553 fps from a 16 inch barrel, 262 fps slower. Hornady's law enforcement data for its .223 Remington 75gr TAP, one data set covering four different firearms, lists 2,385 fps from an 11.5 inch Bushmaster and 2,514 fps from a 16 inch DPMS carbine, 129 fps apart. Across 16 loads chronographed from one set of barrels, a 10.5 inch barrel ran 219 to 420 fps slower than the 16 inch, 326 fps on average. At the two common SBR lengths the HD SBR comes from separate tests: RECOIL measured 2,269 fps from a 10.3 inch MK18, and Hornady lists 2,321 fps from an 11.5 inch test barrel. Barrel length here means the barrel alone, not the rifle's overall length.
▶How far does an SBR load keep expanding from a short barrel?
Hornady designed the 75gr InterLock HD SBR bullet to expand down to 1,900 fps. Solved from its G1 ballistic coefficient of .230 at sea level, it stays above that speed to about 105 yards from a 10.3 inch barrel, 120 yards from an 11.5 inch barrel, and 180 yards from a 16 inch barrel.
▶Does a suppressor count toward barrel length?
No. A suppressor that threads on or locks onto a muzzle device is removable, so it is not part of the barrel and does not count toward the 16 inch minimum or the 26 inch overall length. An 11.5 inch barrel with a SureFire SOCOM556-RC2 is physically about 15.3 inches from the bolt face to the end cap and is still an 11.5 inch barrel to ATF. Only a device that is permanently attached counts.
▶How does the ATF measure barrel length?
From the face of the closed bolt to the muzzle, or to the end of a permanently attached muzzle device. The procedure is a dowel rod pushed down the bore until it stops on the bolt face, marked at the furthest point of the barrel or pinned device, then measured. A rifle whose barrel measures under 16 inches this way is a short-barreled rifle under the National Firearms Act.
▶What counts as permanently attached?
A blind pin with the pin head welded over, a full-fusion gas or electric steel-seam weld, or high-temperature silver solder at 1100 F or hotter. A crush washer, thread locker, or a set screw does not make a device permanent, so a flash hider held on that way adds nothing to the measured barrel.
▶Is a 14.5 inch barrel with a pinned A2 flash hider legal?
No. A standard A2 is 1.75 inches long, but the barrel's 0.62 inch thread tenon sits inside it, so it adds only about 1.13 inches past the muzzle: a pinned 14.5 inch barrel measures about 15.6 inches and is still a short-barreled rifle. It takes a longer device. A pinned SureFire SF3P-556 puts a 14.5 inch barrel at about 16.5 inches, a WARCOMP-556 at about 16.6 inches, and the extended A2 pattern devices exist for exactly this: KAK's 2.06 inch A2 Extended clears 16 inches and BCM sells the A2X to bring a 14.5 inch barrel past 16.1 inches.
▶Is overall length measured with the stock collapsed or extended?
Extended. Overall length runs from the muzzle to the rearmost point of the stock along a line parallel to the bore, and ATF evaluates a collapsible or folding stock in its extended position. An AR-15 carbine with a Magpul MOE stock fully extended has about 18.5 inches behind the bolt face, so a 16 inch barrel puts it near 34.5 inches overall and a 10.3 inch barrel near 28.8 inches, both over the 26 inch line.
▶What makes an AR-15 a short-barreled rifle?
A rifle with a barrel under 16 inches or an overall length under 26 inches is a short-barreled rifle under federal law. With a shoulder stock on an AR-15 lower, the barrel line is the one that matters: every common carbine configuration clears 26 inches overall, while anything under a 16 inch barrel, or under 16 inches with its pinned device, is an SBR. Since October 9, 2026, ATF does not enforce Form 1 or Form 4 approval, registration, or the unregistered-possession offenses for SBRs. That is enforcement discretion, not repeal, and ATF still accepts the forms voluntarily. A dealer sale still runs a Form 4473 and NICS check, and a Form 5320.20 is still required before taking an SBR across state lines. State law is unchanged: California, the District of Columbia, Hawaii, New Jersey, New York, and Rhode Island ban SBRs, and several states tie possession to federal registration.
▶How much length does a suppressor add to an AR-15?
About 5 to 6 inches past the muzzle for the current 5.56 cans. SureFire publishes 3.0 inches added for the SOCOM556-MINI4 and 3.8 inches for the RC2 and RC4, measured past the Fast-Attach flash hider the can locks over; an SF3P already reaches about 2 inches past the muzzle, so an RC2 on it ends about 5.8 inches out. The HUXWRX FLOW 556k adds 4.9 inches over its Flash Hider-QD, and a direct-thread can such as the 6.1 inch Canik VOID-556 reaches about 5.5 inches past the muzzle once the barrel's 0.62 inch thread tenon is inside it.