I use Plan B muzzle devices on all of my rifles and PCCs. This design is based on pla.boi's FTN.5 Breek insert but has been adapted to use the Taper Mount Blast Shield from SLR Rifleworks. This blast shield is compatible with the Plan B standard used by Q, Rearden, Liberty Precision and others.

01/21/2026: Initial release. I am waiting on my Form 1 to be approved, so I have not actually tested this design with live firing. I will provide an update here as soon as I am able to build my 5.56 suppressor and give it a try. I don't recommend you try this with live fire before I do, but if you decide to do it, proceed very carefully and with all necessary caution.

01/30/2026 v2: In v1, the wall at the tip of the Blast Shield was too thin and likely to break, allowing the Blast Shield to migrate forward into the suppressor. To address this issue, the Blast Shield was pulled back by 5mm (away from the suppressor body) to allow for a good, thick retention ring with adequate wall thickness to retain the tip of the Blast Shield properly. This change increases the overall length of the Threaded Insert by 5mm.

02/14/2026 v3: PLA Boi pointed out a weakness in the v2 design that was likely to result in failure. This version moves the rear of the SLR Blast Shield well up into the threaded area to provide needed support. See the ReadMe file for a detailed explanation.

02/16/2026 v3 addendum: I added "Looser Thread" STL and STEP files to be used if you find that the standard version is too tight to thread into your suppressor body. I also added a PDF file that describes how to properly calibrate the Flow Rate for the specific filament and slicer settings that you are using. If you follow these steps prior to printing the suppressor and thread adapter you should find that the standard threads provide a perfect fit.

02/27/2026 v3 addendum: The plate orientation of the parts in the STL and 3MF files has been changed to horizontal instead of vertical. This change takes advantage of the greatly increased shear strength of the XY plane. This version was tested with 100 rounds of live-fire today on a 16" AR-15, and it held up very well.

LBRY Tags: guncad; nfa; suppressor