Clawman, I'm not exactly sure what you mean by a DIRECT comparison. My brother has a 19 Calhoon on the CZ action; bought it directly from Calhoon. My buddy has a 17 Ackley Hornet on a T-C. They've shot them together but never went through the rigamarole of chronographing them or otherwise comparing loads. No doubt the 17 will be a little faster depending on the bullet, but I've never seen ballistic data to see which one might be more likely to buck the wind or shoot flatter. After quite a few years of use my friend says the the 17 is probably limited to maybe 175 yards for the small squirrels we shoot in northern CA (probably less than half the size of a PD), especially in a 20 mph wind. I think my brother feels like he can be pretty consistent out to 200 yards on these small critters.

My way of thinking is that unless you just have to have something different from everybody else, stick to a 17 or go with a 20. Biggest issue is nobody else makes 19 bullets except Calhoon, unless you can get some custom guy to make them. There are so many brands of 20 cal bullets available now it's hard to justify the 19.

-- Edited by Verminator on Tuesday 6th of April 2010 07:19:24 PM

I would look at the relative trajectories and the relative masses of the bullets and impact energy in consideration of what you want to shoot and how far away it is and how big it is. 

The higher the mass of the bullet,  the more destructive force on impact.  The flatter the trajectory, the easier to hit the target.  The more mass, the longer the range, most likely.  Sometimes, the longer the range, the better it is to use a slightly larger bullet.

What will you shoot with the gun and how important is trajectory versus impact energy?  I have been switching from .17 Mach IV to .20 VarTarg, partly for fun, but the impact of the .20 is significantly more powerful and the visual gratification higher on Prairie Dogs.  The bullet mass is about 2x from one to the other.

It seems to me the issue of availability of bullets and the price of bullets is a consideration too. I am a high volume shooter and economy is an issue to me.

Yeah, a 17 Hornet will no doubt kill a ground hog out to 200 yards. Part of the problem of discussing effective range is knowing what the target is and how big it is relative to something else. A decent sized groundhog is maybe 15 inches long and 4-6 inches across (depending on where measured of course). A Belding ground squirrel is about 9 inches long and roughly 2 - 2 1/2 inches across at the widest. The vital zone is roughly 4 times bigger on a groundhog than a Belding ground squirrel. So where a reasonably accurate rifle can routinely hit a groundhog at 200 yards it can be falling apart at that distance to hit something so much smaller.