I am able to get a 27 at a very good price. I want an extension on the mags so I have somewhere to hang my little finger. On of the guys at work said to get 23 mags instead. His reasoning is that the last two rounds dont feed properly, possible stovepipe. My question is: Can / should I get the extensions and add 23 springs or just get the 23 mags and the slip on extension covers? Thanks for your help in advance.