This is my first post on this forum and I wanted to thank oceanbob for inviting me to this forum. From what I have read, the members seem to be very knowledgeable. I was interested in this thread because I also just obtained a Glock 20 recently. The ammo that I plan on shooting, after a lot of research, is Buffalo Bore 10mm 180 gr. JHP. for home protection, and Double Tap 10mm 200gr WFNGC Hardcast for use as my hunting sidearm. I was on the fence about a barrel since I wasn't planning on reloading at this time. I ultimately chose the Lone Wolf Tactical 5.15 in. barrel to get above the 5 inch mark. I also added a 22 lb. guiderod spring due to the fact that I wanted to stay above 700lbs. of energy without ejecting my rounds 30 feet and the slide slamming the back of the gun. These are the upgrades that I made based on my personal preferences as to what the gun needs to do for me. As you can see from the differing opinions on here, a Glock can be easily personalized for what you want to use it for. All will agree that is a good thing. The first question should be to yourself, asking exactly "what do you plan on using your Glock for"? Once you answer that question, the others come easy. Wanna kill these ads? We can help!