Dont have an H&R in 30-30, 'just' a pre-64 Win. SRC
.......and the H&R 357 Mag because the case still holds more powder than I need for my usual sub-sonic, cast bulllet load. I have stoked it up and 'long seated' the bullet for low end 357Max performance to see that it would do, and loaded 9mm jacketed 115gr.RN as a 30Carbine equiv. and for the 30-30 loaded 32-20 equiv. on up to the fulll book loads. I know them both pretty decently, and like them both.
I really (
really) like the user friendliness of the 357, and the readily available bullets with the edge being the larger dia. The 30-30 is a bottleneck case, so it takes a back seat to the straightwall 357 with carbide dies. If I ever become unhappy with the 357 I can rechamber to 357Max, 35 Rem., or the 358 (rimless) or the 356 (semi-rimmed) Win. cartridges and become even more than the 30-30 is.
So, if all I used my rifle for was hunting bigger game then the 30-30 would be a good choice (and it, too, can become a 30-40 Krag or 7.62 X 59, BTW, a fine cartridge). Or just start with a 270. 308 or 30-06.
But since the most of my shooting is fun/pleasure and a little 'varminting', the 357 works well for me, and can do much more within my self imposed restriction of 100yd on larger game.