Javelina are not much challenge. You can shoot them at range if you want to. But it's easy to get within 20 yards. Much closer if you really want to. Sit still and wait and they will come right up to you and sniff your boots.
Shooting over feed is a big sin in the western tradition. I'm not judging. Just saying I wouldn't shoot a game animal over feed. That shot would be illegal in New Mexico. It's fair chase only here. That's the game I play. But others can do whatever they want.
You could kill one with a pencil in his neck if you wanted to. They are super curious. I've got close enough to touch one on several occasions. No food involved. If I had some I think he would have taken it out of my hand.
A bow is fun with javelina. I've taken them with a .22 handgun. They have thin skin and are super easy to kill. For me they are really not the sport animal that would justify a different weapon.
The natives in Hawaii hunt hogs 10x that size barefoot with a stick. That's more like a sporting challenge to me.
We do have a problem with feral hogs. Those rascals can be difficult to locate and tough to set up a shot. They aren't in farmland with ATV roads everywhere like in Texas. They are a huge problem. I've shot many and you could hunt them with a PCP if you were so inclined. But it certainly would not be the gun I would hunt with.
I know a spot where there are hundreds of turtles. You could shoot out to 150 yards. You couldn't shoot a firearm in this spot. But you could shoot an air rifle all day every day for months and not run out of targets. The heads are tiny. Their backs are armor plated. They are half submerged at the surface. That seems like the best PCP target I can come up with around here.
I get a kick out of shooting from a boat. Bowfishing carp is a passion. Frogs too.
There is a guy on that show "swamp people" He's a fairly unimpressive cat with a garish rifle that misses a lot of simple shots on alligators. But he shoots off the bow of the boat and that's pretty cool. I think a PCP would be cool from the bow of the boat sniping bullfrogs and turtles. Maybe even carp at the surface when they come up.
I think a .22 cal would work just fine. One that could hit a nickel at 100 yards would give you enough range to play with. A pair of binoculars to spot. You could have a bunch of fun and stay in targets all day. Set some lines and catch catfish while you were plinking. There are plenty of rock squirrels on the banks and those would present a target too.
If I were to invest in a PCP I think that would be the game. Off the bow of the boat in the morning before the waves kicked up. When the water got too rough for an accurate shot you could transition to the bow.
I think I'll take the springer out and try it. If I can't get enough range or impact to be effective I'm going to take someone with a PCP out and see if it's a thing. It's the only game I can think of that would justify a new gun and all that goes with it.
Urban prairie dogs in Santa Fe was a big thing. Dozens of guys shot them out of their truck windows at intersections with short PCP's. They had a club going and had contests. Someone in traffic saw a guy take one in a median while stopped at a stoplight. It became a huge issue and a few guys got in trouble. I admit it wasn't the safest or most ethical hunt but it was pretty cool. I might have been doing it if I'd thought of it before they were busted.
Anyhoo I'm going to give it a shot. Maybe I'll decide to get a PCP going this winter. If I can rig it as a boat gun and modify my bowfishing deck a little it could be a bunch of fun.