34.1 grains of reloader 15 is alliants max load for the 170 grain. It's also the most accurate load I've ever fired from my 1971 30-30.
NOTE: this load is hot, it's a true max load, and I found it stretched brass in my older rifles.
I managed a .75" group with the load once. Had my wife for a witness.
I'd bet I can't do that again!
I don't actually USE that load for hunting. I don't need that power. The load I used to take the bull moose with was a dose of 4895 (29 grains) under a Hornady 170 grain interlock. It's quite accurate, and doesn't stretch the crap outa my brass in any of my guns.
With that load, I can neck size.
TIP:
If you can neck size only the top portion of the neck, the bullet will be less likely to be pushed back in the tube mag.
When neck sizing for a 30-30, be sure to run all your cartridges through the chamber once before you take them hunting, in case of tight fit.
Most tight fits, can be squeezed home anyway, but not something you want to be doing when hunting.