The CMMG DEFCAN 45 Gen 2 .45 ACP suppressor is a full-auto rated pistol-caliber can built for .45 ACP hosts (brand part no. 45CA453). CMMG gives it a Reduced Backpressure System that vents gas forward and away from the shooter while cutting back pressure in the operating system, which matters on a blowback carbine or SMG. It attaches with a tri-lug QD mount that locks onto the included .45 ACP 3-lug muzzle adapter, threaded .578-28, and a locking release button frees it again. The body and mount use the industry-standard 1.375×24 HUB interface, so other QD mounts can be swapped in later. The sealed design and Cerakote finish keep maintenance simple.

Key Specifications

• The caliber is .45 ACP, with the 3-lug adapter made for calibers up to .45.
• Length is 8.3 inches, a full-size pistol-caliber can.
• Diameter is 1.81 inches, a large tube for big-bore pistol gas.
• Weight is 15.6 ounces, as CMMG publishes it for the DEFCAN-45.
• Construction is stainless steel and aluminum, with a Cerakote finish.
• The mount is a tri-lug QD that clicks onto the included 3-lug muzzle adapter.
• The included adapter is threaded .578-28, the common .45 ACP barrel thread.
• The body is 1.375×24 HUB compatible, so the mount can be changed to another HUB QD system.
• It is full-auto rated with no minimum barrel length, per CMMG’s firing schedule.
• The Reduced Backpressure System vents gas forward and away from the operator.

Frequently Asked Questions

Will the 9mm DEFCAN adapter fit this suppressor? No. CMMG says the 3-lug mounts on the DEFCAN-9 and DEFCAN-45 are different diameters and are not cross compatible, so use the .45 ACP adapter that ships with this can.

Do I need ATF approval to buy this? No. As of October 9, 2026, ATF no longer requires Form 4 approval, registration or a tax stamp for suppressors. It transfers on a Form 4473 with a background check through a Class 3 (SOT) dealer. State and local laws still apply.

Is there a minimum barrel length? No. CMMG rates the DEFCAN-45 for full-auto fire with no minimum barrel length restriction.

Buy the CMMG DEFCAN 45 Gen 2 .45 ACP Suppressor, 3-Lug QD

A big-bore pistol can that clicks on and off a 3-lug adapter is the practical choice for a .45 carbine or SMG. As of October 9, 2026, this suppressor transfers on a Form 4473 with a background check at your Class 3 (SOT) dealer, with no Form 4 or tax stamp; state and local laws still apply. Order through CMMG‘s silencers and suppressed firearms lineup and our Lubbock, Texas team will handle the transfer, and it ships fast to your Class 3 dealer.