Jan 31, 2007 · A collation is a definition for how each character is represented, stored and compared. Part of the collation setting, known as case sensitivity, determines if an upper case “A” and a low case “a” when compared against either. other are the same or different. If the collation is case-insensitive then a. lower case “a” and an upper .... Mar 28, 2021 · The 16-inch taper 9mm barrel is accurate for shooting at distance. This upper is compatible with lowers that use both Colt or a Glock mag. The Gen 2 9mm bolt-carrier group, charging handle, and A-2 style flash hider are all included for a complete drop-in-ready setup. 6. CMMG 9mm Upper Receiver.. "/>Best matched upper and lower