First time posting here. I discovered this forum while researching 10mm reloading and it has been a valued resource! Well I am picking up a new Glock 20 in 10mm next week and cant wait start shooting it.. As a result of all the research I was doing I discovered that it is suggested that one pick up an aftermarket barrel, spring and guide. What I have on my Midway wish list is; Storm Lake 4.6 SS barrel Wolff 22# recoil spring Wolff Guide Rod Im also new to Glocks.. So I have some questions. I understand the reasoning behind the heavier recoil spring, keeping the cartridge in battery longer to ensure a complete powder burn and in turn reducing velocity spreads. And I understand that an aftermarket barrel will have a tighter chamber (easier on brass) and the chamber is cut so more brass is supported unlike the factory barrel, but.. I see the recoil spring set has two springs. Is one for the extractor? What is meant by supported and unsupported recoil spring? Ive e been a handloader since the late 60s and have loaded many different rounds over the years, including .40 S&W, but never any 10mm I am aware of the situation with autoloaders where the bullet in reloaded ammo might have a tendency to slip back in the case upon ramping into the chamber thereby increasing chamber pressures catastrophically. One way to reduce or illuminate this problem is to use a powder that results in a slightly compressed result. Thats why I like to use BlueDot with 9mm Luger. In using 180-200 grain bullets in 10mm, there should be plenty of bullet tension in the case since they are seated deeply. Is this a conern? I threw a lot out at one time.. Hope thats ok.. I really appreciate your help.