The GSL GT-300K suppressor is a fully welded stainless steel can from GSL Technology, rated for full-auto fire (brand part no. GT-300K-SUP). GSL says it handles .300 Blackout subsonic, standard and supersonic loads, so one can covers both quiet and full-power ammunition. It measures 6.25 inches long and 1.5 inches across and weighs 18 ounces. A High Temp Cerakote finish and a 5/8×24 direct thread mount suit a hard-used .300 Blackout AR.

Key Specifications

• The caliber is .300 Blackout, covering subsonic, standard and supersonic loads.
• GSL publishes a sound reduction of 30 dB.
• Length is 6.25 inches, compact on a short .300 Blackout upper.
• Diameter is 1.5 inches, a standard rifle-can profile.
• Weight is 18 ounces, the trade for a stainless build.
• Construction is fully welded stainless steel under a High Temp Cerakote finish, and GSL rates it full-auto.
• The mount is a 5/8×24 direct thread, the standard .30 caliber muzzle thread.

Frequently Asked Questions

Which .300 Blackout loads can it handle? GSL states the GT-300K handles .300 Blackout subsonic, standard and supersonic loads.

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 it full-auto rated? Yes. GSL lists the GT-300K as full-auto rated.

Buy the GSL Technology GT-300K Suppressor, .300 Blackout, Stainless

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 GSL Technology‘s silencers and suppressors lineup and our Lubbock, Texas team will handle the transfer.