I feel the 30-30 is way underpowered, however plenty of stuff larger than deer have been killed with it.
I thought like that when I was 16-30 years old . the older I get (46 now) the more I like the 30-30. Of course back then I needed a 12 ga pump to hunt rabbits and quail now the scattergun I use is a youth 28 ga H&R. The only animal in north America that I would hesitate to hunt with the 30-30 is the big bears.
Tim
I have an old 157 H&R with the barrel length fore arm in 30-30 A.I. I haven't lost a case fire forming who ever did the rechamber went a tad deep and it has to be headspaced on the shoulder
Since we can't deer hunt with rifles I mostly shoot cast bullets out of it 113 gr cast @1100 f.p.s make one ragged whole at 50 yards 170 gr cast @ 1725 f.p.s. shoot inside 2 inches with a make shift rest at 100 yards, fire forming loads seem to hit what ever dirt clod on the back stop that needs shootin,
I really wish it was a standard 30-30 but I like the way it handles so unless I run across the same gun in 30-30 I guess I'll keep it

Roy