Lets all remember the design and physical performance limits of air rifles, regardless of powerplant. Air rifles are designed to be effective, accurate, efficient tools at 10 - 50 yds. Yes, decent 100 yard accuracy is possible with the right equipment, shooter and conditions. The biggest limitation is the ballistic characterists of diablo pellets. They pretty much have the B.C. of a rock. Diablo pelletes shed velocity and energy very quickly and are dramatically affected by wind. Nothing at all wrong with trying out the long range capabilities of any air rifle, as long as it in the right venue, ie. at a safe shooting range.
The biggest thing I'd like everyone to take from this thread is that it's OK to disagree with an idea or concept, as long as you do it respectfully. Attack ideas, not people.