ive tested with frontier 124gr plated and the match grade, also with campro plated and blue bullets ( the plated and blues are even worse then the zeroes), hornady HAP projectiles cost about 220$CAD/1000 so those are too expensive for my taste. ( this is a uspsa/IPSC pistol) , i did some measuring last night and while pushing the barrel down into the slide the barrel can move forward about 0.0030, when i push down and forward i can see a tiny sliver of light between the breech face and the barrel hood. this sti is factory brand new barrel wise ive probably put about 20-30,000 rounds thru it.