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Avoid 90-degree vertical foregrips on handguns/braced kits unless you have registered the firearm as an AOW or SBR. If you want extra control, stick to factory-integrated hand stops or angled grips, or consult the manufacturer’s documentation. The MCK does not have a vertical foregrip option.

• There are few quick things to review if you’re having trouble fitting your pistol in your MCK:
  • Aftermarket parts such as threaded barrels, sights, back straps, frame alterations can alter your pistol’s footprint and cause binding or mis-alignment.
  • Double check pistol compatibility. Be sure your handgun matches your MCK model and the handgun model is stamped on the inside left wall of your MCK. 
  • Adjust your barrel shroud to be sure it is the correct position for your compact or full size firearm. The ship is configured for compact pistols, so it will not seat properly if you try to fit a full size handgun without adjusting the barrel shroud. 
  • Insertion technique is critical to ensure the frame rail of your pistol aligns with the rails inside your MCK. Line up the grooves and smoothly push the pistol forward until it clicks into place. Watch the official step-by-step demonstration here: Proper MX1 & EVO Insertion Technique Video. 

Always remove the handgun before cleaning the MCK chassis. Heavy carbon fouling accumulates inside the front muzzle shroud and around the ejection port. Clean these areas using a soft nylon brush and polymer-safe cleaners/degreasers. Avoid aggressive harsh solvents (e.g., acetone or harsh mineral spirits), as they can degrade or discolor the synthetic polymer housing.

• MCK 1.0 (Gen 1): Original, slim/compact product design, non-suppressor and RMR compatible.
• MCK 2.0 (Gen 2): Accommodates suppressors up to 1.38″, fires in folded brace position, and adds a push-button integrated spare mag release catch. Not RMR compatible.
• MCK 3.0 (Gen 3): Suppressor ready up to 1.5” dia. RMR Compatible. Redesigned charging system that attaches directly to the slide backplate.
• MCK EVO (4.0): One Chassis, 120+ Handguns such as Glock, SIG Sauer, Smith & Wesson, Taurus, CZ, HK, and more.
  • AR-Style Charging System: perfectly smooth, fully ambidextrous AR-style charging system for unparalleled ergonomics and speed.
  • Slimmest Design Yet: By hugging the pistol tightly and removing unnecessary external bulk, it operates as the slimmest and lightest chassis in the CAA lineup.
  • Aerospace and Defence Quality: Equipped with metal from front to back, the EVO is solid, holds zero, and trusted by the United States Air Force.

https://caagearup.com/mck-buyers-guide

• Manual Safeties: MCK units are not compatible with handguns that feature external manual frame safeties (such as specific M&P or Ruger variants) because internal clearances prevent proper operation.
• Backstraps: Large aftermarket backstraps or extended beaver tails block the horizontal clearance required for the rear hatch door to latch securely and must be removed.
• Ambidextrous Slide Releases: If your handgun has an ambidextrous slide release, it may have issues fitting inside the MCK Chassis. 

Because the optic is mounted to the MCK’s external Picatinny rail while the barrel is part of the internal firearm, slight mechanical tolerances exist. While the setup holds exceptional group accuracy, you may experience a minor shift in zero when removing and re-inserting the handgun. Sights should always be quick-checked/re-zeroed after reassembly.

• MCK 1.0 (Gen 1): Not suppressor compatible.
• MCK 2.0 and 3.0 (Gen 2 and Gen 3): Compatible with suppressors. The front muzzle shroud on Gen 2/3 accommodates suppressors up to 1.38 inches in outer diameter. Larger suppressors will rub or fail to fit inside the shroud.
• MCK 3.0 (Gen 3): Will fit suppressors up to 1.5”
• MCK EVO (4.0): Suppressor-compatible when paired with a 9″ or longer aftermarket barrel for proper clearance. CAA Gear UP has these available for sale. 
• We recommend using a suppressor with a booster/Nielsen device to ensure the best level of functionality. Also, using subsonic ammo will help. You may need to do some experimentation if you see failures since all ammo is not created equal.

No. Compensators physically will not pass through the front muzzle shroud. Ported barrels and slides vent high-pressure, superheated combustion gases upward inside the closed polymer chassis. This can melt or warp the polymer structure, causing extreme fouling build-up, or pose a safety hazard to the shooter’s hand.

• Slide-Mounted Red Dots: Depends on the MCK version.
  • The only version that you can run your red dot on is the MCK 3.0 (Gen 3). 
  • MCK 1.0 and 2.0 (Gens 1 & 2) will not accept a slide-mounted red dot. It must be removed from the handgun slide prior to installation. Optics must be mounted to the MCK’s top Picatinny rail.
• Aftermarket Iron Sights: MCKs are engineered around standard OEM iron sight profiles. MCK 1.0 and 2.0 (Gen 2 and Gen 3) models accommodate some standard-length suppressor-height sights, but oversized/wide sights (e.g., TruGlo, Ameriglo, Leupold Bullseye) will prevent the charging handle from seating.

First, ensure the handgun’s rear factory sight is sitting fully inside the dedicated sight pocket on the underside of the charging handle. If the sight sits too high, the handle rides above the slide serrations and strips. Second, verify you are using the correct handle—some kits ship with two handles (e.g., Gen 3 Glock vs. Gen 4/5 Glock slide geometry). Upgraded full-serration handles are available if heavy wear occurs.

• Cycling issues inside the chassis are typically caused by one of three installation factors:
  1. Improper Insertion Angle: The pistol must be inserted straight and completely level into the internal Picatinny rail lock. If inserted at an upward angle before locking, the slide will rub against the upper body.
  2. Charging Handle Fitment: If the handgun slide isn’t fully seated into the charging handle notches, friction will prevent the slide from completing a full stroke.
  3. Optic Over-tightening: Top-rail accessories clamped too tightly near the ejection port can slightly flex the polymer chassis and choke the slide travel.

• It depends on the rear attachment model:
  • Stabilizer Brace: Keeps the platform classified as a handgun/pistol under federal ATF rules (subject to current regional brace regulations) and does not require Form 1 submission.
  • Rigid Shoulder Stock (NFA Variant): Attaching a solid shoulder stock converts the handgun into a Short-Barreled Rifle (SBR) under the National Firearms Act (NFA). This requires ATF approval via a Form 1 submission before assembly.
    • A $200 Tax Stamp fee was once required, but recent legislation removed that requirement.