A 400 Legend suppressor must be rated for .40-caliber bullets or larger; in practice that usually means a .45-caliber centerfire rifle suppressor that its maker lists for 400 Legend. For the semi-automatic CM15 400 Legend with supersonic hunting ammunition, Chattahoochee Munitions recommends a flow-through suppressor, which vents gas forward and keeps back-pressure down in the AR15 action. Chattahoochee Munitions manufactures the 400 Legend as a 16-inch CM15 AR15 rifle and as 16-inch and 10.5-inch uppers.

400 Legend Suppressor Requirements

Requirement	What to check
Bore rating	.4005-inch bullet, so a .40 or .45-caliber rated suppressor
Cartridge rating	The maker lists 400 Legend, or an equal or higher pressure and bore
Mount	Matches the barrel’s thread pitch or muzzle device
Design for the CM15	Flow-through, for supersonic hunting ammunition

Winchester lists the 400 Legend’s .4005-inch bullet diameter on its Power-Point product page.

Why Flow-Through for the 400 Legend CM15?

Chattahoochee Munitions’ rule for every semi-automatic rifle it manufactures: supersonic ammunition, flow-through suppressor; subsonic ammunition, enclosed suppressor. A conventional baffle-stack design raises back-pressure in a gas-operated AR15, sending more gas and fouling into the action and toward the shooter. The CM15 400 Legend is a supersonic hunting rifle, so the 400 Legend suppressor recommendation is flow-through. Its Superlative Arms adjustable gas block and ODIN adjustable buffer help tune the cycle once the suppressor is on.

400 Legend Suppressor Thread Pitch on the CM15

Complete CM15 400 Legend rifles: 16-inch 416R stainless 1:16 barrel threaded 11/16×24, shipped with a Chattahoochee Munitions muzzle device.
CM15 400 Legend 16-inch upper: 416R HBAR barrel threaded 5/8×24, with a muzzle device or thread protector.
CM15 400 Legend 10.5-inch pistol upper: CrMV barrel threaded 5/8×24, with a suppressor-host muzzle device or thread protector. See the 10.5-inch 400 Legend pistol upper.

Thread pitch alone does not establish compatibility. Match the suppressor’s mount and confirm bore clearance for the .40-caliber bullet with the suppressor maker.

Subsonic 400 Legend

Winchester sells a 300 gr Super Suppressed 400 Legend load at subsonic velocity for target and range use. Chattahoochee Munitions makes no subsonic cycling claim for the CM15 400 Legend. With supersonic hunting loads a suppressor reduces muzzle blast, but the bullet’s sonic crack remains. For subsonic-first rifles, see the 375 Raptor subsonic and 458 SOCOM XL.

400 Legend Suppressor Legal Notes

Suppressors are regulated under the National Firearms Act, and some states prohibit ownership or hunting use. Check federal, state and local law. Re-confirm zero with the suppressor attached.

400 Legend Suppressor FAQ

Can you suppress a 400 Legend?

Yes, with a suppressor rated for .40-caliber bullets or larger.

What caliber suppressor for 400 Legend?

A .40 or .45-caliber rated centerfire rifle suppressor that its maker lists for 400 Legend.

Will a 350 Legend suppressor fit a 400 Legend?

Only if it is rated for .40 caliber or larger. A .36-caliber can rated for 350 Legend is too small. See 350 Legend suppressor.

Flow-through or enclosed for a 400 Legend AR15?

Flow-through, for the supersonic hunting ammunition the CM15 400 Legend is designed for.

Do the 400 Legend uppers accept a suppressor?

Yes. The 16-inch 400 Legend upper and the 10.5-inch 400 Legend pistol upper are both threaded 5/8×24 and come with a muzzle device or thread protector.

Who makes a threaded 400 Legend AR15?

Chattahoochee Munitions manufactures the CM15 400 Legend semi auto rifle with a threaded 16-inch barrel, at Hall of Legends.

400 Legend Suppressor: .40-Caliber Bore, Flow-Through and Thread Pitch