In order to install and use the 45 ACP magazine extension, certain parts of your CX4 will need to be modified. Please read these notes carefully before ordering a magazine extension kit so that you are fully aware of what is involved in modifying your CX4 before you order the parts.
The most significant modification will need to be made to your original 45 ACP magazines. If you look at the magazines you will notice that there is an elongated depression, or dimple, on both sides of the magazine near the base plate. These depressions are designed to prevent the loading of more than 8 rounds into the original magazine and they must be removed in order to use the magazine extension. This modification permits the use of the magazine with the magazine extension and it does not cause any problems with using the modified magazine in its original 8 round configuration when required. This mag material is very tough and will rapidly ruin non-specialist tools. While you can perform this mod yourself, we recommend you have SierraPapa perform the mod. There is a $20/mag fee for this service.
Magazine Adapter Mod
The final modification is to the magazine adapter that fits inside the gun's grip. The ramp at the lower rear part of the adapter will need to be removed to permit the modified magazine to fully seat in the grip. The ramp does not serve any useful function in routine use. Its purpose is to make the insertion of the magazine a little easier. This may be an important function with a hand gun but it is not a significant aid in the case of a long gun.