I'll jump out of the gate with this: Most folks will recommend a centerfire cartridge for any kind of hunting - which largely IS necessary for coyotes/fox/bobcat and larger - but for what it seems you're looking to do, you'll be fine with a rimfire.
When you say Varmints, many of us immediately think of shooting coyotes at 250yrds or blasting prairie dogs out as far as we can hit them. It doesn't sound like that's what you're looking to do. Looks like you're looking for a handy little small game gun to carry in the woods and work on hunting & marksmanship skills by hunting small game. A 22LR would do just fine in this role as well, with the best ammo availability and lowest cost of any of them. The 17HMR DOES have a bit more range and power, and is also a great choice.
Originally Posted by
Vuk0321
I'm wondering what the best all around round for shooting varmint (digger squirrel and wood pecker, sometimes coyote in my case).
The cartridge I'm really curious about is the 17HMR. How does it compare to a 22lr?
The .17HMR will be fine for short range small game busting.
It's too small for coyotes. Great for rabbits, crow, squirrel, etc. I LOVE the round in both the Savage 93 and Taurus Tracker for small game blasting.
The .17HMR is the same cartridge case as a 22 mag (win mag rimfire), only necked down to a 17 caliber bullet. Both of which are much more powerful and flatter shooting than the 22 Long Rifle.
Originally Posted by
Vuk0321
Also I read that either a 410 shotgun or a 20 gauge with size 6 brass would be a good option.
A 20ga or .410 is a fine option also, again, for short range busting. Not "size 6 brass," but size 6 shot. The .410 is too small for coyotes, but the 20ga is a reasonable choice.
Other options:
The 22mag is a great option for these small game species as well. With heavier bullets than the 17HMR, it hits harder than the 17HMR at range. Still too small for coyotes.
If you want to step up a little more in power, a .17WSM is a viable option. Still too small for coyotes, but good for 250yrds+ on small game like rabbits and squirrels, assuming you're able to connect on target.
If you're really thinking coyotes will be a common target, then you DO need to step up to a centerfire round. The 223rem is quite likely the ideal coyote cartridge, although it's very much over powered for bunnies and squirrels. Ammo is cheap and easy to find.
The 22 Hornet is a good option, a little less overkill than the 223rem, but still enough punch to take down coyotes at short range. Ammo is still pretty cheap, and still easy to find.
Larger cartridges like 220 swift, 22-250, 243win, etc are more expensive, more powerful, and really would be more power than you need.
Originally Posted by
alleyyooper
Were it me I would stay away from any rim fire ammo.
If I were interested in a 17 I would go with a ... 17WSM.
17WSM is a Rimfire round.