Being a fairly New Guy to this sport I am not qualified to judge the worthiness of Un-announced Chrono's. But I think I was at the match in question, AND was one of the guys who's ammo failed the Chrono,, and I thought it was OK, "So Be IT", being new to Reloading as well, I just loaded from the manual,so it was a good lesson for me. Anyway I failed the check, my comment is that some of the folks who also failed did not sign the test sheets either on purpose or accidentally, and RUMOR had it, that there were some who tested ammo from a special box. NOW I agree that the Rules are the Rules,,but no one checked the weight of the bullets tested, and no one made sure the tests were signed, so if we are going to have Surprise Chronos,, then let's do it right..