I've shot lots of IMR4198 in the .30-'06 with cast Lead bullets. So long as the Lead bullet fits the groove diameter and the Lead bullet design is compatible with the rifling design, they shoot really well together.
Before you do anything, decide what you are trying to do by trying reduced loads: cut recoil, cut costs, cut noise, or something else? You'll cut recoil a lot more by going to a lighter bullet. Faster powders will cut noise. Sticking with Jacketed bullets will not cut costs much.
I've never tried 4198 with Jacketed bullets in the '06. If I was going to load a Jacketed bullet down, I'd probably use something like 4895 (it is forgiving), or SR4759 with 125gr bullets. There's a very famous article from years ago that talks about "the load", featuring either a Cast or Jacketed bullet in .30-'06 class cartridges, powered by Red Dot.
Cast bullets are not difficult, within limits. If you're going to go over about 1300 fps, use a gas checked design. Bell your case mouths slightly so you can insert bullets without damage. Be really careful not to double charge with powder or your rifle will spontaneously disassemble itself.
Cast bullets are cheaper than Jacketed, especially if you cast them yourself or bum them from somebody who does. They can be bought:
http://www.westernbullet.com/30caliber.html
https://secure25.securewebsession.com/proshootpro.com/order.htm
http://www.montanabulletworks.com/page5.html