Yote - I've owned and played extensively with all the Hotrod .22's from the K-Hornet up to the Swift. (Including the .221) I would go along with most things the others have said about it. For sure it's a loveable little cartridge. But there are some shortcomings you should be aware of.

First, no way you will have the power, speed, range, bullet selection of even a 222.

Second, I question any improvement in accuracy. The 222 for example is almost legendary for it's accuracy and a good 223 is no slouch either. But then all these little guys are danged accurate.

The less recoil, noise, etc are going to be minor reductions.

I guess what I'm saying is you can get more gun and fewer hassles by sticking with the larger calibers. For simple coyote hunting, a 223 is a good choice. A 22/250 a better choice.

I would think of a Fireball as a 150 - 200 yd rifle. Yes it will hit and kill further but it's running out of gusto mighty fast.

VG, your assumption is correct about my Fireball days. It was in a galaxy far, far away.

And indeed your data for current possibilities is impressive.

One of the hazards of becoming an old fart is we learn that many of the things we thought we knew and had often learned the hard way...no longer apply.

Thank you for your comments and reminding me of this. Jim

Pecos45: Apparently you played with the 221 Fireball some time ago! The new powders and pointy new Polymer-Tipped bullets have turned the 221 Fireball into a real performer! I now use a load that shows no pressure signs what so ever and has been widely described in the last year by many shooters of the 221 Fireball.
The load uses the 40 gr. Nosler Ballistic Tips, Remington factory brass, Federal 205M primers and 16.0 grs. of Hodgdons Lil'Gun powder. It gives 3,400 FPS in my 24 inch barreled Remington and the trajectory chart reads like this:

100 yards = +1.30"

200 yards = 0.0"

300 yards = -6.8"

and at 300 yards the extremely lethal Nosler Ballistic Tip is still perking along at 2,150 FPS! I would hate to be hit with that bullet at that speed anytime! By the way this load has been published as giving only 48,900 C.U.P.!
With the superb accuracy of the 221 Fireball 300 yard hits on Varmints are easily done. With a rangefinder 400 yard plus hits are very do able!
You stated that there are some hassles using the Fireball cartridge in a Rifle? I have been loading for and shooting my 221 Fireball Kimber Ultra Varmint Rifle since 1994 and my Remington 700 since Febraury 2,003 and have yet to run into hassle #1! The Fireball is easy and VERY economical to load for and performs really well at the range and in the Varmint fields.
Accuracy is certainly hard to quantify or compare, gun to gun - day to day - barrel to barrel etc. But if I were pressed to make a comparison of 221 Fireball accuracy to the 223 and the 222 I would comment that I feel the 221 Fireball is going to be more often more accurate than a 223 in comparable Rifles and at least as accurate as a 222! I know thats saying a lot! But that is how impressed I have been with the Fireballs accuracy in Rifles.
You mentioned bullet selection being inferior with the 221 Fireball than the 222 - well I contend that for the vast majority of those here on the Accurate Reloading Forum the bullet selection for reloaders of these two cartridges is the same.
As far as comparing the speed of a 221 to a 222 lets stick with the 40 gr. Nosler Ballistic Tips and the latest Nosler Manual (Fifth Edition) - the highest velocity - MAXIMUM loading - for the 222 Remington is 3,564 FPS. Lets remember back to my 221 Fireball loading (with the same bullet) of 3,400 FPS so an improvement with the much larger case in the 222 is 164 FPS! Two things are obvious here (besides your obvious statement in your posting that the Fireball is not as fast as the 222!) and they are this, the Fireball is a very EFFICIENT cartridge and the 222 is not much faster than a 221 using the popular 40 gr. projectiles! A quick check of the latest Sierra Manual (Fifth Edition also) shows their maximum loading in the 222 Remington with 40 gr. projectiles of several types as being loaded to 3,400 FPS! Hmm....
One could say then, using my illustration that the 222 is at most 4% faster than a Fireball - not enough in my experience to describe as a "shortcoming" for the Fireball.
Hold into the wind
VarmintGuy