MAXIMIZE YOUR CAPACITY: 23 ROUNDS FOR 140MM & 21 ROUNDS FOR 126MM
Transform your factory tubes into competition-ready powerhouses with the MBX Comp Extension Kit. This premium upgrade package includes our advanced MBX Spring and proprietary S Follower Set that extends to 141.25mm for maximum capacity without compromising reliability.
COMPATIBLE WITH:
- STACCATO/STI Factory Tubes
- Springfield Factory Tubes
- SVI/Infinity Factory Tubes
- Checkmate/Atlas Factory Tubes
- BUL/Armscor/Para Factory Tubes
In order to achieve 23rds you may need the help of a loading device. I may take a little break-in time for the spring to set and sit correctly in the tube. Please be patient we have spend many hours developing the sets so we know the capacity with factory spec ammo.
Follower 3D Printed: Our Followers are made from a specific blend of material 2e have developed for this purpose and are 3D printed. If you are against the look or simply the ideal and feel this is not for you than please do not purchase. Remember the facts are MBX has been the most innovative company in the magazine business for Reliability, Performance, Capacity and part of that is Developing Innovative 3D follower Designs that simply can not be effectively molded.
MBX Notes for new spring and followers sets
MBX is not responsible for the quality and problem solving of other manufacturers tubes and feeding. We have provided a proven spring and follower that will perform if the tubes/ammo are good. Some manufacturer's tubes may have "soft fed lips" that will open out easily or bend if dropped. Other factory tubes may require additional adjustment "tuning" in order to perform correctly. This is not the responsibility of MBX.
Specs for competition
We used these in testing for over 15,000 rds! We don't want to cause any "controversy" with the mag "tuning gurus." This is what Adrian, who designs all our mags used in testing.
9 mm generic specs, we can only suggest is the front feed lips which needs to be less narrowing .005 -.007 of the rear lips. For Example, rear Measures .345 front to be set .340-.338. All 9mm ammo oal 1.145-1.165 max, crimp factory specs "very important" crimp around .372 we really only round nose .38 super comp max oal 1.255.
Springs/follower
If the design is good, it will work with very little pressure. Don't get all concerned because the spring lost length! It will!
The spring we use on these competition kits is not new. It has presented millions or rounds flawlessly over the last 10 years. Replace your main mag springs every 6 / 8 months if regular used. Adjust if you shoot more or less than average 2-3 matches a month.
