I picked up a KKM 10mm to .40 conversion barrel a few months back to save a little money and give me an extra caliber option (which there are many for the G20, .22lr, .40, 9×25 Dillon, .40 Super, list goes on, another great reason to get a G20). There are a lot of Glock barrel manufacturers (Lone Wolf, Bar-Sto, Storm Lake are some of the more popular options), all with good reputations, but in my research the name KKM kept coming up for best of the bunch so I decided to spend a bit extra and go with them.
The first ammo I put through it was Fiocchi 165gr and I was immediately concerned. The slide was moving very slowly, and sometimes wouldn’t seat the following round completely. I was worried it was a problem with the barrel but it turned out the stock spring is just too stiff for the Fiocchi ammo. I tried a mag of Winchester White Box and another of UMC and both cycled fine. During the filming of the video I shot several hundred rounds of both PMC and Sellier and Bellot and it cycled 100%.
The accuracy is great- with any of the ammo I’ve used I can keep the groups under 5″ at 25 yards quite easily. I haven’t shot it out of a vice or off bags (just forearms resting on the bench) but it is probably capable of a bit more accuracy than that. Accuracy great, function perfect, what else could you want? Oh… it’s shiny