I'm not a hunter specifically but I have done enough long range shooting to share that a high power .22 can hang with a similar .30 out to 100y. The .30 ends up being more loopy and sensitive to your distance measurement but tends to hit harder at distance. In terms of ballistic coefficient, the right .22 can keep up with most .30s. Since airgun hunting potency relies on both accuracy and power, and real-world accuracy is heavily influenced by wind drift, I guess my point is I'm not giving the .30 a big advantage. And .25 is right in the sweet spot between them.
If there is a SCUBA shop nearby who can do 4000+psi fills, you might consider getting started with a big 4500psi tank. But keep in mind those high power PCPs will drain a big tank down to 250bar (which is a common max fill pressure for bottle PCP guns) in several refills, which might only add up to a hundred or two hundred shots. I think you'll need the big tank regardless since you're traveling to shoot. **
** there are portable compressors that run on generator or even your truck electric but I'm not too familiar with them. And I'm still a fan of the big fill tank.
I'd love to say there is a price point where compressors become dead reliable, but unfortunately that price point is around $4k. Spending $1k or $2k on a compressor probably helps but that does not eliminate reliability issues. There is a growing segment of airgunners who buy cheap (<$400) compressors, add water cooling, don't lean too hard on them, rebuild as required, and make them work for a tiny cost compared to the other options. Me, I picked up a $2k compressor in a local sale for $900 or so and knock on wood it's handled my weekly fills of my big tank for two years now.
There are some brands of PCP that have ample adjustments for regulator pressure, hammer spring preload, and port size. They can allow relatively large changes in tune relatively easily, but in my experience these are more complicated designs and a bit less reliable. (not unlike comparing Campy 12 speed to Shimano 10 speed) I'm a fan of the simpler, more durable high performers like the RAWs and Daystate mechanical guns. But there are many options and they can all work.
Make sure you buy scopes that focus as close as 15y minimum, preferably 10y minimum. I like FFP reticles for the kind of shooting you describe since I can rely on holdover charts and not be stuck taking my shot at one magnification.
Slugs are a big thing these days and ballistically awesome but I still think only a minority of PCP shooters have been successful with them. In a word, not for beginners. If I experiment with slug shooting again, I will buy a dedicated slug gun and get right to working out the perfect slug selection and tune. Pellets are way more forgiving and still quite accurate and powerful.
