The magazine will work on all the RTI versions.
The magazine needs to break in, so as soon as you receive it insert it on the gun all the way until it clicks, initially it will be really tight, but after inserting and removing a couple of times it will start feeling much more better.
Number of Shots per Caliber
.177 cal - 14 shots
.22 cal - 12 shots
.25 cal - 10 shots
.30 cal - 8 shots