If you fool around on rimfirecentral very much, you will find your complaint of leading with Thunderbolts is VERY common, almost everyone has a complaint or twelve with the stuff. It's just crap.
Instead of shooting the cheapest crap you can find, try something a bit better. There are alternatives that do NOT lead like Thunderturds, in the same price range. Federal bulk box ammo usually shoots like crap in my rifles, but it's better than anything Remington produces now.
In the immortal words of Doc Campbell, on HeeHaw, "If it hurts when you do that, don't do that."
