I loaded some a few years ago for my handi-rifle.
Got better accuracy out of the flat base Pro Hunters, which were a little cheaper.
https://www.midsouthshooterssupply.com/item.asp?sku=000072130Don't have that gun or another 30-30. Have a 30-06 now, but I stayed with Pro Hunters.
Now, the Gamekings were great in my high velocity calibers, 130 in 270, 55 in 22-250.
On a mag fed gun, you need to watch OAL. The boattail uses up some of the surface that the brass bearing surface that is available on a flat base bullet, and the GK is looooongggg. In other words, less room for powder.
Seems like I saw a discussion, maybe here, on the the GK's needing a certain velocity to expand, and by the time you got out to the longer range you want to reach out to, the bullet would not expand even though it had good energy. 30-30 bullets are segregated by the manufacturers because their jackets are thinner to expand at the lower 30-30 velocities. Don't take this statement as law, just as a starting point for a more discussion and search.
https://www.midsouthshooterssupply.com/item.asp?sku=000072000You could post a WTB in the classifieds for a handful of 150 GKs, or trade for some.