It is unfortunate that Glock did not take the sf series a step further and branch the G20 and G21 frames away from each other. A tenth of an inch width is important to all marksmen, and a deal breaker for the majority of those who try the large frame grip. In an era of computer assisted design and manufacturing, there is little cost advantage in maintaining a common frame with identical magazine well. Same can be said about the magazine body, follower, etc. 10mm magazines need be no wider than 40sw magazines, only more ample in the fore and aft dimension. For those who like to barrel swap, the G21 could still shoot the 10mm with magazines available today. For those only interested in 10mm to smaller base cartridge conversions, the G20 would still accommodate and provide for those who require or desire a smaller grip frame. I have read that Glock will now manufacture 6" hunting barrels for the G20. They do not mention long slides, which seems an obvious product for a manufacturer that recognizes their customers are demanding longer barrels!