It is critical that a 30-30 load is not too long. A long round will hang up in the transfer from the mag to the chamber and jam the gun.
If you seat the bullet deep enough to get the correct OAL, you may find that the mouth of the case is past the cylindrical section of the bullet.
If it is just a bit past, you could file the nose of the bullet, to make it shorter, so you could seat a bit longer. When I do something like this, I cut the nose off with a side cutter, then trim with a file.
Or, just seat the bullet deep enough to fit the chamber and practice with the rifle, single loading.
I would start with 28.0 gr of BLC2.