That IR119 would be a very nice air hammer choice. Depending on how you use air hammers, you may want to buy a rivet hammer instead for more control. I hardly ever use my air hammer any more since buying rivet hammers for solid rivet projects.

CP714 is my normal use 401 shank. Good for most stuff, but it's not driving out press-in ball joints, or cutting 3/8 rivet heads off quickly. It's all about unscrewing rotted hardware for exhausts with ultimate trigger control and what not. It'll do most u-joints, knocking out frozen bolts from bushings, punching out exhaust studs after you heat up the flanges a bit, rattling tie-rod jam nuts free of rust, etc. I have a 498 shank Astro Pneumatic big-nasty for ball joints, wheel bearing hubs, although frankly I run into situations where I'd like even more punch than that. I made a thread on here asking about even bigger options, and finally admitted I'm basically looking for a death-ray.
What are you doing with it? What do you work on?
I have a Chicago Pneumatic CP7150, I like it but with the new CP7165 out id try it instead. The trigger looks like a "tip" trigger that you "should" be able to feather, the cp7150 is not and is on or off. I just adjust air pressure if need be. I've not used others to compare but its a brute.
For what it's worth, I've seen some favorable reviews of the Harbor freight Chief air hammer.
Sent from my SM-T720 using Tapatalk
IMO you're almost in the market for two air hammers. For removing the ball joint rivets on the lower control arm on older GM trucks, I like to cut an X in the top of the rivet (just remove the CV axle, or set it on top of the sway bar link). Then, knock the pie-pieces off the top, and you're ready to do battle punching them downwards. Those things can be a massive PITA, even with a 498 hammer if you're unlucky. A normal 401 shank can get the job done with this method on something like the rear leaf spring shackle mounting brackets, since there is less material for the rivet to be stuck in. To do sheet metal work, and thrash ball joint rivets, you really want two different things.
If you're just talking about dealing with stuck bolts and whatnot, a 401 should do fine. Trigger control is key for cutting metal, some of the cheaper guns in either 401 or 498 are on/off switches. One can regulate the air going into the hammer with a regulator to slow down the aggressiveness. My 714 has a built in regulator knob for this.
I recently purchased the Chief air hammer from Harbor Freight. It is identical to the one from Mactco and a third of the cost. It out performers the best from Snap On. All this for $139.99. When you pull the trigger you had better have a hold of it. Variable speed trigger. It removed ball joints easily.