This season, the "Gun-Broker-couldn't-pass-up-deal" Contender carried it's weight during early season small game with a .410 barrel, and deer with a 30/30 barrel. I'm really liking this all-season, any-game Contender system quite a lot.

But, it's still new to me. I want to add a 10-14" rimfire barrel, preferably a scoped .22 Mag or .17 HMR to take advantage of the slightly better quality ammo and slightly longer range (over .22LR), but don't really know what would be the best choice since I don't have any experience with rimfire .17 and .22 Mag handguns, other than my lone iron-sighted 6.5" Single Six.

I do know that I've hunted many a season with a .22LR levergun and .22 Mag revolver which is great up until the last of the oak leaves came down, and then a .17HMR rifle after that through the last day of the season, when the lack of cover makes squirrels, um, "squirrely" and 50+ yd. shots were the norm.

So bringing the Contender into the late season game is the natural progression. There's a big variety of factory barrels that pop up occasionally on Ebay and GunBroker in .22 Mag, and to a lesser extent, .17 HMR. Beautifully blued octagon 10-inchers, modern G2-capable 14-inchers, and everything in-between, including a Bullberry custom tube once in a while.

So my questions are such, from someone interested in shooting barrels instead of just collecting them:

1) What accuracy and reliability could one expect from TC rimfire barrels, both older and newer variants?
2) Are the aftermarket barrels so much better in accuracy that the extra premium paid to obtain a new one in your choice of caliber and length is worth it, over a factory tube?
3) For all intents and purposes, shooting squirrels and rabbits, is there any appreciable difference in terminal ballistics between the .17 HMR and .22 Mag inside 100 yds. fired out of a handgun?

There's a couple very nice .22 Mag shiny blued octagon 10"-ers out there right now, but I wouldn't want to buy one and be disappointed in accuracy and range performance.

Help?