The +4 magazine follower is made from very durable injection molded glass filled nylon. It is designed as a direct replacement for the standard factory follower. When installed it increases the magazine capacity from 10 to 14 rounds of .22lr. When the magazine is filled to 14 round capacity, it can be difficult to fully seat with the slide forward.
The magazine fed flawlessly when using CCI Mini-mag round nose ammunition. Other .22lr ammunition which had a waxy coating tended to jam and mis-feed from the magazine.
Instillation of the follower can be carried out by anyone. Care must be taken when disassembling the magazine as the spring is under tension.
- Remove the plastic base plate
- Remove the plastic follower floor plate
- Remove the magazine spring (Observe orientation of spring)
- Slide follower all the way down to the bottom of the magazine body.
- Slide the metal pin out (It can only be removed from one side)
- Install the upgraded +4 follower
- Install the magazine spring in the correct orientation
- Fit floor plate and base plate
The standard follower and pin are not required when the +4 follower is fitted. 
The image to the left shows the +4 follower and an aftermarket base plate fitted. The image to the right shows a magazine fitted with the standard follower and baseplate.
The +4 follower has a load assist hole which is only visible once the magazine contains 2-3rounds. Aftermarket magazine filler assist pins are available but these can be around $20.
This follower can be used with Sig Sauer / GSG / ATI 1911-22 magazines.
Followers are also available for the Sig Mosquito, S&W and other .22 pistols.
This follower was supplied by GSG-Pro at $5.95 per follower. There are many other manufacturers and suppliers who also stock this product design.
