It may seem contradictory, but I am inclined to agree with both Brian AND Marvin. In the traditional sense and based upon the way Reelfoot calls were originally designed, running one is immensely different than an AR style. However, being the maker of said calls, one can make them to be tremendously similar to an AR call by changing certain aspects of the call. My preferred slope is 6°, I'm torn between 4" and 4.5" on the barrel length. I have run 5" barrels which do require noticeably more air, as well as shorter barrels which seem to make it easier to choke up, I have also varied the slope from 4.5° to 8°, it seemed like the higher the slope the louder the call got and a longer barrel made it easier to get the air under the reed. I settled in at 6° after a lot of tweaking, finally deciding that I have found a nice middle ground between the high hails of a traditional Reelfoot and the ducky lows you can typically get with a J-frame. Now, all of my testing the tonality may mean absolutely nothing as I cut each reed by hand and there will certainly be inconsistencies in doing so, not to mention that different sections of the same reed material can vary in thickness and resilience. I do know that they sound pretty darn good and you can run 'em like nobody's business without hacking up a lung. More importantly, the only thing that quacks like a Reelfoot is a mallard hen.