At a Glance:
Fully metallic lower replacing factory plastic
Fully assembled and upgraded with all TANDEMKROSS parts and accessories
“Drop-in” ready out of the box
Compatible with virtually ALL factory Ruger® Mark IV™ and Mark IV™ 22/45™ uppers
The #TANDEMIZED Cthulhu Lower is the single best way to get the most out of your Ruger® Mark IV™ Standard or 22/45™ pistol. What was once a stripped lower that required additional parts and assembly is now ready to host your pistol’s upper right out of the box! Increase the life and durability of your pistol while also increasing its reliability and performance!
The Cthulhu Lower boasts an enlarged trigger guard for large or gloved hands, a hooked trigger guard for more points of contact, and textured backstrap for improved grip and ergonomics. Additionally, the takedown button has been replaced by a single takedown screw that helps preserve the pistol’s simple takedown while reducing play between the lower and upper for a firm, secure hold. The cerakoted aluminum is also less susceptible to damage from heat, chemicals, impact, or general wear and tear.
The Cthulhu Lower will support virtually any factory Ruger® Mark IV™ or Mark IV™ 22/45™ upper. This means the Cthulhu Lower allows you to transform any Standard Ruger® Mark IV™ into a Mark IV™ 22/45™! Swap your factory Mark IV™ magazine base pads with our Mark IV™ 22/45™ base pads. Try either the two-pack of Tomahawk or MarkPRO Magazine Bumpers.
This upgrade contains over 30 parts, components, and accessories, all from TANDEMKROSS and all fully installed, assembled, tested, and ready to go as soon as it arrives at your door. Whether for serious competition or recreational plinking, the #TANDEMIZED Cthulhu Lower is perfect for anyone looking to improve their favorite rimfire pistol.
Choose your favorite color TANDEMKROSS Cthulhu Lower and all black or all red accessories! Get the #TANDEMIZED Cthulhu Lower for your Ruger® Mark IV™ or Mark IV™ 22/45™ today and make your good gun GREAT!
With the #TANDEMIZED Cthulhu Lower you’ll receive:
IMPORTANT: This product complies with ATF RULING 2009-2
Any person who installs “drop in” replacement parts in or on existing, fully assembled firearms does not manufacture a firearm and does not need to be licensed as a manufacturer under the Gun Control Act. A “drop in” replacement part is one that can be installed in or on an existing, fully assembled firearm without drilling, cutting, or machining. A replacement part, whether factory original or otherwise, has the same design, function, substantially the same dimensions, and does not otherwise affect the manner in which the weapon expels a projectile by the action of an explosive. Any person who is licensed as a dealer, which includes a gunsmith, and who installs “drop in” replacement parts in or on existing, fully assembled firearms as described in this ruling does not need to be licensed as a manufacturer under the Gun Control Act. Any person who is engaged in the business of installing “drop in” replacement parts in or on existing, fully assembled firearms as described in this ruling must be licensed as a dealer, which includes a gunsmith, under the Gun Control Act.
This item is NOT considered an “80% Lower” and Complies with Rule 2021 R-05F
The full definition can be found here: https://www.atf.gov/rules-and-regulations/definition-frame-or-receiver/summary
This product is NOT a serialized part.
*Rebuild kit comes pre-installed and does not include the tackle box.
INTERNATIONAL CUSTOMERS: Because the TANDEMKROSS Lower is a frame, it is NOT available for direct international sales.
This product is protected against mechanical failure for life by TANDEMKROSS’s Lifetime Guarantee. Learn more about our warranty and returns policies here.
WARNING: This product can expose you to chemicals including chromium, which is known to the State of California to cause reproductive harm. For more information go to www.P65Warnings.ca.gov