Any recommendations for an air rifle that can ethically take a groundhog?

Would a .22 work, or am I looking at a big bore?

A PCP .22 that can be tuned up to push the heavy 25 grain pellets at 800 ft/s would be sufficient, but that in my opinion is about minimum.  A .25 PCP is easier to get the velocity to 840 to 880 ft/s with 25 to 33 grain pellet, which would be better.  The slightly larger diameter makes a bit bigger wound channel, and is more likely to hit vital areas.  The .25 will use more air than a .22 but for the few shots taken at critters like that filling should not be too much of a problem.  

Oh, and keep your shots to a maximum of 60 yards.  Pellets lose quite a bit of energy as you reach out.  You might think that you could then push the pellet faster so that you do have down range energy, but the problem then becomes stability with the pellet and accuracy suffers tremendously.    The velocity at which pellets go haywire is typically around 900 ft/s.  Some guns can seem to do o.k. a bit faster while others somewhat slower.

Round nosed pellets do quite well on critters, and often better than the hollow points or the plastic tipped pellets.  The possible exception is on smaller critters and closer where the expansion does not prevent adequate penetration to vital areas.

Agree with the above advice.

Those critters can be tough and I recommend a clean headshot.

A typical airgun is producing less energy with a subsonic 22 pellet than what you are used to in a rimfire, much less.

So make sure you can place the shot in the brain pan.

They are slower than squirrels, but are still quick enough and jumpy if they see you stalking.

Good Luck and Good Hunting.

I have used a stock .22 Benjamin Marauder to harvest over 125 groundhog over the last few years from 10-60 yards and have had only about three run to the hole. These were mostly subhurbian GH were noise was a concern to the property owner. Love that gun- n mostshots were with the standard crosman premier domed .22 14.4 pellet

Thanks all.

I’m in the city, sandwiched next to a bank and nursing home behind me, with a city police officer 4 houses down, so traditional guns aren’t an option.  I’m thinking air rifle out the window is my best option.

Have a heart trap and a garbage can of water is a safer bet after hearing where you live.

If you go the airgun route above advice for sure. Just make sure your not gonna get yourself caught up in a law for the city your not aware of.

Most places around here have no discharge laws and minimum distance to building's if hunting.

Yea in town, depending on the laws of your town it could be real bad.  In many towns they see no differences between a pellet gun and a 50BMG.

I get on my high horse about ethical and IMHO a 22 is just so close.....I would want a little more room for error.  As to taking one at 60 yards with a stock Mrod, again IMHO that is not ethical, I have chrono'ed pellets at 50 yards and some brands loose 40% of their speed at 50 yards, things like Pred's bleed speed so darn quick.