RXM Plasticcatto Grip Module Open Beta

DISCLAIMER: This is considered an OPEN BETA! I overbuilt the model for safety and heft but I don’t have the huge support network like the big names do, so please reach out if you’d like to share your results, have questions or concerns, or anything else! I’m on FB, IG, X, Discord, Makerworld… I’d love to see your build!

THIS IS NOT A FRAME, IT IS A GRIP! Follow your local laws but this is not governed under the same rules as a normal frame/lower due to the FCU being the serialized part.

RG3D RXM Plasticcatto Open Beta

Overview & Changes
Gunder_Mifflin adapted MPMS’s Plasticcatto design to accept RXM components and an FCU. I built on that work and refined it further. All non-RXM pins and bolts were replaced with bolts I already had on hand.
 

The compensator was updated so it now installs without any plate-chamfering—fully plug-and-play. I changed the SCS plate to use M3 hardware, though users with the original version can simply drill out the holes. The printed portion of the compensator was also revised to use the same M3 hardware with captured nuts, improving printability, support removal, and overall assembly. The front compensator bolt was resized for an M3 with a captured nut, and the brass-rod holes were enlarged for easier assembly (a ⅜" drill bit may still be required).
 

I added a printable mag catch that works reliably with the PMAGs supplied with the RXM. Other magazines were not tested—please share compatibility feedback.
 

Gunder’s logos were replaced with my own, just as he had previously replaced MPMS’s; this was partly for consistency and partly as a learning exercise in Fusion. I created a smaller backstrap to suit my personal preference, but all original Plasticcatto backstraps from MPMS remain compatible and are included in the provided STEP file. The magwell required only minor cleanup to correct some geometry issues, likely caused by translation between different CAD programs.
 

The holster was further resized to accommodate socket-head screws securing the top plate, and the assembly was converted to use M5 hardware instead of the original barrel-nut system.
 

A left-handed version is included. It is fully untested, but the geometry mirrors the standard model wherever feasible. Note that the slide release remains right-handed due to the FCU design.

Assembly
Assembly is no different than any other grip module. See RXM instruction manual. One of the easiest 3D2A build out there in my opinion. Helpful Tips: Install slide lock spring first. Use a punch/allen wrench from the opposite side to line up the square sided hole with some leverage and carefully push in the pin, it can walk. Then push the rear pin in to lock the FCU in place. Removed the need to use the takedown spring. Key note would be make sure you're not galling the threads on the hardware when assembling the compensator. Just take your time and it will be fine. As an added tip I put the nuts on the bolts and use the bolts as a press-in tool for the nuts into their captured positions. A small deadblow came in handy getting the compensator to seat properly, just make sure you clean up all the support interface areas. I put the brass rods in my drill and hit them with a brillo pad for a good polish.

BOM
1x) RXM
1x) Glock/rxm mag release spring
1x) SCS Top Plate for Compensator (In .step file)
2x) Brass Rods 9.5mm x 65mm
1x) M3 x 30mm with nut - front bolt in compensator
4x) M3 x 40mm with nuts - Top plate in compensator
1x) M2.5 x 25mm with nut - Compensator attachment point
1x) M2.5 x 20mm - Back strap
1x) M2.5 x 20mm - Flared magwell
2x) M5 x 20mm with nut - holster clamp
1x) M5 x 12mm with nut - fork mount

Accreditations
MostlyPeacefulMachineShop - Original Plasticatto Design files and reference cad
https://odysee.com/@TheGatalog-PrintableFramesReceivers:9/PLASTICCATTO:6

Gunder Mifflin - RXM x Plasticatto main conversion work
https://makerworld.com/en/models/1831271-rxm-plasticcatto-grip-module-beta#profileId-1955583

Chairmanwon - RXM Staged Hardware
https://odysee.com/@chairmanwon:a/RXM_Chairmanwon:7

DannyMeatball - Staged Magazine
https://odysee.com/@DannyMeatball:b/DMB-Glock-Mags-(v1.1):1