Recoil Rob,
You can always go the insert route. MCA will custom make a 22 mag adapter for your chamber.
http://www.mcace.com/rifleinserts.htmlAlso, I believe many of drilling makers offer full barrel inserts as well. Unless of course, you have your heart set on a new drilling.

A .243 would be great round for javelina and serve for antelope as well.
You could look at the Merkel 96K 12x12x243 or the Blaser D99 20x20x222 or the Krieghoff trumpf dural 12x12x270
Speaking of the San Carlos... I came very close to doing a do-it-yourself lion hunt there about a year ago. Seems they have way too many lions. The reservation biologist gets daily reports and she is more than willing to share this information. The fees are some of the cheapest around.
Pete
Pete, I'm not a big fan of new guns (or their prices). I have to admit I like the thrill of the hunt, I'll find an older gun.
Just last week a friend was cleaning out some drawers and gave me some old ammo to sell and along with it he had two 12ga. chamber inserts. One is .22LR the other is a strange one indeed. It's a 12ga chamber insert for firing .22 shotshells. Made of brass, has a tube that opens up to a small blunderbuss affair, stamped BARRELETT-PATENTED. Maybe for shooting song birds by naturalists?
Anyway, I can't see how those 22 inserts can be all that accurate. I imagine you put them in semi-permanently, zero the scope to the insert? Nah. I can always use another drilling.

BTW, this year at the San Carlos when you bought your javelina tag you were given a free lion tag that could be used up until the time you shot your pig. I've hunted their 3 times and haven't seen a lion but then again I wasn't looking and didn't have dogs. You going to bring dogs out from Illinois?
I'd like to get a lion, I have read from several sources that mountain lion meat is one of the best of all game meats. The members of the Lewis and Clarke expedition preferred it above all else. And those guys ate a lot of meat.
If you're interested in coming out with us next year give a yell.I have a group that meets there, we stay at the casino. Last year I got my pig the first day and had to keep the carcass in the bath tub with ice.

Be fun to try that with a lion.
Granite, that Hollenbeck sound perfect for peegs and quail, do you use it for that?
Vol717, I imagine any gunsmith that lines barrels could do that work, did he specialize in break open guns?
Rob