OK, OK...I feel really stupid, but I know what the problem was. I started comparing my barrel, where the gas system is, to a schematic. The Gas Cylinder was GONE, and the Gas Cylinder Retainer (a little split washer) was also missing. I don't have a clue how they were lost. I hunted using that barrel 3 years ago and it worked fine. The next year I had a Remington 30" barrel polished by Denny Tubbs and I've used it to hunt the last two years. I decided to shed some length and weight and went back to the 25" barrel. I never inspected the barrel or the gas system, I just shoved it in the receiver and locked it down. The ONLY place that 25" barrel has been is in my gunsafe. I checked the floor of my safe - no Gas Cylinder. It's a mystery, one of the like I am very familiar with. Stupid crap happens to me and I never catch it; I have to do what I did today to find out what mechanical issue is screwing with my firearm, whichever one I happen to be shooting at the time.