I have to agree with Byron. I have run into the same thing with firearm dealers. When they hear you say you are looking for a predator rifle, they grab the closest bull barrel varmint rifle off the rack. I have several bull barrel bolt guns I use for groundhogs and sage rats and wouldn't consider lugging one of them around for calling predators. Nothing against anyone who chooses to do so of course. What a fella chooses for his hunting is his business. It's all personal preference and I'm not about to suggest my way is the right way. Use whatever works for you.
Regarding ARs, I have 16", 18", 20", 24" rifles. The one I use least is the 16" and the one I use most is the 24". Some snub their nose at a 24" but it has stacked more coyotes for me than all the rest combined. It handles like a dream, is super accurate, is much more pleasant on my ears and I notice a performance edge over my shorter ARs. The 24" is one I built long before Bushmaster offered their Varminter but is essentially the same rifle. It has the deep cut barrel fluting and is quite light for a long AR. 8.5 lbs with the scope on my digital scale.
Having said that, if a guy is out to get one AR for predator hunting I would probably go for a deep fluted 20" like the new one Bushmaster is now offering. It is the best of both worlds. For those that get distressed about longer barrels, and others that worry about velocity loss, the 20" is a good compromise between a 16" and 24". One thing great about ARs though is you can build more uppers and swap them out with the push of a pin to suit your needs. Whatever you get, rest assured you will end up with arguably the most effective calling rifle available and that's a great start. Got the honey do's done so I'm grabbing mine and going right now. /ubbthreads/images/graemlins/smile.gif
Good hunting