CTM CNC UnderMount Picatinny Stock Adapter for Hi-Capa

Hi-Capas are designed as pistols, but in SQB and SpeedSoft formats they're often pressed into duty as primary weapons. Without a stock that's an awkward firing position — wrists carrying the recoil load, sight picture wobbling with every breath. Adding an undermount Picatinny rail lets you fit a rear stock (your choice of design) and the platform transforms: cheek weld, shoulder contact, and proper two-point bracing.

Most players assume an undermount adapter conflicts with kit like the REAPER conversion or other lower-frame additions. CTM specifically tested this and the adapter works alongside those systems rather than against them. It also pairs cleanly with the CTM CNC Large Flared Magwell (the matching new-arrival listing) — running both together gives you the most stable Hi-Capa-with-stock configuration the platform supports.

Construction is 6061 CNC aluminium, 60g weight, precision-machined to drop onto the Tokyo Marui Hi-Capa lower frame without fitting work. Colour-matched options across the line, with the Electroplated Rainbow finish carrying a small premium for the more expensive chameleon process.

Specifications