I have a Gen 4 model 26 & 19 set up the same way... XS Big Dot nightsights, ext slide release, trigger bars & springs, KKM barrels, ect... I bought two 50 rd boxes of Federal HST 147 +P ammo to test and I was really impressed with the ammo BUT it will not shoot in the G26 KKM barrel. The empty brass is coming out of the chamber and the next round runs under it and jams it up every time. I put the stock barrel back in the G26 and it shoots fine. The G19 runs fine with the KKM barrel no problems. I was looking to carry the G26 with the KKM barrel loaded with the HST 147 +P but thats not going to happen. Anyone else running a G26/KKM barrel/HST 147 +P set up out there?