as a slow learner and very poor pistol shot, I have found that a slightly more than book maximum of AA #9 with a 200 grain bullet has not bulged the case with a gen 4 glock 20. If I found a gen 2 for $300, I guess the barrel upgrade would be reasonable, or maybe just buy a new gen 4 gun. I know lone wolf barrels had been unsupported chambers just like the glock barrels, not sure on a kkm.
