Dude you don't have to unscrew the tube to get access to the spring. When you take off the cap in the front and remove the barrel you will notice in the from of the tube there seems to be a cap that looks like it won't come out because the end is crimped get a large flat heat stick it in that cap and screw in about 1/8 of a turn do that the notch in the cap lines with the crimp in the tube and pops out mind you, you need to do this pushing the cap in a little. Once the cap comes off just pull the spring out and follower. If you feel the spring has lost some tension give it an attitude adjustment and stretch it out a bit to gain more tension. You don't need any special tools. The only reason to take out the mag tube is if it's bent or dented because it can cause feeding or loading issues.