How to clean and adjust a Glock 27 round 45 acp pinned magazine

[Doors of Perception]

I have a 27 round glock 45 acp pinned magazine and I have a JR carbine. I need to disassemble the mag in order to adjust the spring follower angle as per JR instructions. When I remove the base plate I cant remove the spring as it hangs up on the two pop rivits - I did not try forcing it as that may go terribly wrong.

Do I need to send it to a licensed gun smith to remove the rivets and adjust the spring angle?

Thanks