The split ring will take a little "persuasion" to move and then remove, in a perfect world, a pair of pliers that open when the handles are squeezed, and a flat tip at right angle to the pliers, to insert in the center of the ring just behind the flat surface that the plug is now resting against and pull straight out would be perfect. I don't seem to have anything made quite that way, so I insert the tip of a flat screwdriver behind it padded with a small cloth and gently pry towards the magazine cap a little at a time, working it out slowly from side to side, it takes a little practice but patience is key, once it is out far enough you will see the shoulder protruding out of the end of the magazine tube, this is when I grab a shop rag, and place it over the end of the tube, re-insert the screw driver and cover with one hand while pulling out the split ring with the other to catch the magazine spring ,and split collar together. It has tension but not a lot, it is not dangerous, just very surprising, protect your eyes with glasses. I have never seen an A5 that would require the replacing of the magazine spring or split collar, just keep them clean. Powder residue tends to eventually build up on the metal piece the first shell you load into the magazine rests against, this is what I am calling a follower, as you load more shells the crud travels up the magazine tube, that is why I suggest a lube that will stay dry so as not to attract any dirt or powder but still prevent any rust from building up inside the magazine tube, I have seen quite a few of them that were very dirty in this area, a spot usually overlooked when routine cleaning is performed.