1.) What is the difference between the Handi Rifle and the Ultra Varmit? I assume some type of accuracy addition to the ultra.
The Handis come with synthetic or plain wood stocks, some with a plain laminated wood. The Ultras have resin laminated or the new fluted Ultra have a partial skeltonized stock, also, they have a longer scope rail with support on the over hang which is nice when mounting longer scopes.
http://www.hr1871.com/firearms/index.php?cat=42.) Are there any models that I should try to stay away from?
The super light barrels have a hot/cold history, some shoot excellent, others don't. Not an issue if you get the .223, it's got an excellent track record with few exceptions. The 22-250 is a new again caliber, not many out there yet to tell.
3.) What is the process of ordering extra barrels? Do the extra barrels drop in or do they need gunsmith work. I have heard barrels can be had for less than $100. Compared to the contender barrels, this is great.
Accessory barrels will cost $110-$135, most around $110 after all shipping is paid, you send your frame in minus the barrel, they fit the barrel and return a complete gun to you. Some choose to remove the butt stock to save weight and keep it from being damaged.
http://hr1871.com/barrelAcc/index.htm4.) Does anyone see any problems with ordering one in 223 or 22-250 and then buying a 22 mag barrel for after dark fox hunting?
The rimfire barrels can't be fired on a centerfire frame and vise-versa, the firing pin location is different and the rimfire frames are not strong enough even if pin location were different. Rimfire and shotgun frames are designated as SS1 and SB1, centerfire rifle frames as SB2, SB2 frames are heat treated to stand the much high pressures of the non-magnum rifle calibers. You would need to buy a Sportster in the caliber of choice, which isn't much more than a fitted acc barrel which run $94-$98, a complete Sportster can be bought for $104 from Walmart, an Ultra 22mag for $134.