Yeah, that was what I wanted mine for, groundhogs. I was a genuine rifle loony back even then, and the little bottleneck looked cool, and provided zip over the .22 lr, and shells were about $3.50 a box!. It was the first rifle that I shot for group, understood trajectory a bit, and made hits on game past 75 yds or so.
Dad was against it, said one didn't need a "special rifle" to hunt groundhogs, but Christmas morning a note leading me around the house and eventually to the rifle in the basement was the way it went.
If a few other mfg's had made firearms for the 5mm, it may have flown, but as it was, it was 20+ yrs before its time.