The Colorado Division of Wildlife has seen fit to consider the groundhog AKA marmot,to be an edible species,therefore placing a bag limit of 2 per day on them,possesion limit of 4.The season runs the middle of August to the middle of October. Our prairie dogs,considered inedible,also have a season for public land from the middle of June to the middle of February and no limit,on private land the season is year round.This is what happens when the state wildlife and forestry units are over run by environuts.
Here,in the South West mountains of CO. groundhog shooting usually involves wide draws,canyons and long parks so a cartridge capable of long range is needed,and,if you plan on eating your kill something that does not destroy much . The OP is not about prairie dog shooting ,but around here if it goes bang it is going to get used