What powders do you have now? IMR4198 was a benchrest winner decades ago when the .222 Rem was "the" cartridge to win benchrest matches. H322 is also an excellent choice.
Changing charge weight does the same thing as as adding weight or moving it at the muzzle end. All both do is change the point where the bullet exits the muzzle as it whips up and down vertically. It's cheaper to change the charge weight than how much weight's on the muzzle or where it's at. Besides, a weight on the muzzle end needs to be moved if another load's used, so I think it's best to just change charge weight and/or powder type.
In the following burn rate chart, item 70 through 74 all all excellent for the .222. Use stick/extruded powder for best accuracy; ball powder's never been popular for best accuracy in any rifle cartridge.
That YHM 3200 at $500.00 is probably going to be a waste of money anyway. If you cannot get the barrel to shoot well with a different load, I doubt it'll do any better with that silencer on its muzzle. And what if it's not the barrel's problem? Something about the reloads may be the cause; tools, setup, component choices. And, just maybe, it's neither the rifle or the ammo that's at fault.
One thing to check; does the stock's fore end touch the barrel at any place? If so, that's guaranteed to be an accuracy detriment.