Not even close in my experience. Airguns sound like movie silencers at the loudest. The sound of a BB hitting a metal trashcan is louder even when pushing the pressure way past what is recommended. A .22 CB still has the distinctive crack of a firearm.

I've been thinking about that a lot myself. I've had a .177 air rifle since I was a kid and it's a very simple to use, dependable system. My first air gun was actually second hand and pretty old when I got it. Aside from replacing the gasket a couple of times over the years it's still in perfectly good shape.

A decent airgun would definitely be an asset in skilled hands. It's way more accurate than a slingshot or thrown rock. Really, the accuracy is downright amazing at short range. I bought a Czech air rifle for under $100 and from a fixed position it will shoot a 3/8" group at 10y any day even with cheap ammo. This is more than good enough for taking headshots on small game with .177.

The main problem as I see it however is the lack of power (and short range). .177 would be just enough to take a small bird, mouse or squirrel at 10 yards at most (might be necessary to put a scope on the gun to ensure a clean hit). Maybe a very powerful .177 could take a rabbit with a headshot but I'm not sure. I've never shot a .22 air gun so I can't tell the difference. But all in all, these guns are seriously underpowered and at the same time bulky enough to be pretty cumbersome on the move.

It's a real shame there's no reasonably compact, large caliber air gun on the market (multi pump might be ideal on the trail) at an accessible price. Maybe something along the lines of the old Girandoni (repeating rifle w/ 20 shot capacity, about as powerful as .38 Special). http://www.beemans.net/Austrian%20airguns.htm

I wouldn't try anything with a gun that only shoots 400 FPS. Paintball guns shoot about 300 FPS, though at a higher caliber... which might cause less damage.

Anyway, off track. Gamo makes single pump air rifles in .177 (and I believe "shotgun" versions). Some of their guns will shoot up to 1200 FPS. They also sell specific ammo that supposedly increases the speed up to 25%. If you're dead bent on getting an air rifle, theoretically you could get one that shoots 1600 FPS.

I have taken small game (rabitts, and squirles) with .22 cb caps fired from a ruger 10/22 with a muzzle velocity of 350fps they did a great job within 25-30 ft.

Ditto. I have also had great success with the CB caps in a youth single shot or a TC Contender. I don't leave these in my BOB, yet they would leave with me .
kmat

Some of the crack may be due to breaking the speed of sound (about 1100 fps), but I noticed someone said the CB ammo is much slower than that. However, be that as it may, an airgun that shoots faster than the speed of sound will make a very audible crack too, just like a whip will. This added velocity may not get you much in the practical sense except more racket.

My personal airgun hunting preference is a .20 cal Beeman R1. This is a top-quality accurate, extremely dependable and longlasting combination for plinking or filling a pot. Not only that, but there is an extensive manual on tweaking, repairing, and maintaining the R1 that was published some years ago by the operator of a very popular airgun website (The Beeman R1 - Supermagnum Air Rifle, by Tom Gaylord). It's a worthwhile addition to any R1 owner's survival library.

The caps are what? Don't forget that the 22 has a bit greater mass. I doubt it's a big difference in total kinetic energy though, given the slow muzzle velocity.

Given the choice between my pellet gun and my 10/22, I'd probably take the Ruger.

I've use these as well, and other a bit more crud left in the cylinder of my old K-22 I wasn't unhappy. And yes, those with a .22LR gives your more versatility.

However, what the airguns have going for them is that they are not regulated as firearms. That can make a difference at times, along with being nearly silent (a CB cap is NOT as quite a .20 air gun) and relative sizes of the ammunition.

Different tools, different people.

I'll have to look at the Beeman. Every airgun I've seen all are under 1100 fps. IIRC the CB ammo does have a subsonic slug speed. The crack is from the propellant gases as they exit the barrel.

I haven't tried hunting with one but the Crossman model I had 28 years ago would put a good dent in a 70's steel trashcan at that range.