It’s not the calibre, it’s the twist rate. So be careful with the .222, because despite remaining legal for lead, you might find no one brings in lead ammo or stocks the components you need. You might also find that due to the very small quantities of lead ammo that will be carried, it will become more expensive than non-toxic. Due to the difficulties of getting the .222 to perform with non-toxic, a subject I’ve discussed with the MD of Schultz Larsen, unless You have an old one you love, do consider the .223 or .22-250 instead. And, trust me, I love a .222!!!
As for going up from the .243 to handle non-toxic better for ‘tougher deer’. I’m all for it, shot bucket loads of stags with my .243’s, but past 150yds or even closer, even with good ammo, they lacked at times (not always), needing second or third shots to put a beast down. Not because of poor shot placement, just not enough oomph to create hydrostatic shock or quick bleed related shock and so on.
Some will argue it’s all about shot placement, it isn’t, it’s a lot about bullet design and construction, then speed at which it’s delivered, and then, placement. If you neck shoot, sure, even a tough old warrior or sika stag will drop with a short barreled .243 if hit in the right place, but stick one in the lungs from 275yds and have a block of commercial timber just within reach, good luck
Give really good consideration to what rifle you want, have it fitted to the right LOP, make sure your local shop has plenty of ongoing supply of ammunition that suits YOUR chosen and preferred shot placement, at a range YOU are comfortable with. And, in a twist rate that’s suitable for said round, not what the dealer has in stock, because a lot of stock is old now, even new rifles, and made for the lead ammo market.
I’d forget all about prc’s and magnums and wsm’s etc, and focus on a good solid calibre that feeds well, lots of ammo available, and doesn’t burn the barrel, nor requires a 26”
Barrel to get the best of it.
A 270 is wonderful, but wasted if chopped much shorter than 24”. Same with 7mm rem mag, waste of recoil, powder and pain.
A 6.5x55 in 20-22” would be my best recommendation, had it not been for the lack of good ammunition, loaded to perform. Now it’s really a handloaders round, unless you buy in bulk and have stock for a years stalking or more of course.
Or a good 7x57!
But if you like shorter barrels and reload, 7-08!!!!
But, alas, it’s back to commercially available ammo, as well as rifles actually made! So, we return to the 6.5cm and the 30-06 in my opinion.
If moderated, neither are a big deal, I’ve seen many boys and girls shoot the ‘06 without issues or fear.
But, it needs to be in a rifle that fits you, right LOP, and not 14.5” if you’re 5’6” tall!!!!!
Why am I not talking about the .308? I detest the .308. Small, short and stubby, ugly, underperforming IMHO, don’t like it..had several, all sold.
Just, not elegant. I’m, I’m being too harsh, it’s just not one I like really
My view. Sorry Pat

don’t take it personally.
Go and try some rifles, find the one you like that has, or can have the right LOP, then check cals it’s available in, if it has the right twist rate or can be ordered for such. Commercially plentiful, so parts not an issue,
Good reputation for accuracy, and service. Buy from a dealer you have a good working relationship with.
Go try some rifles in a few different calibres,
Don’t pick based on what I, or others recommend. But, at least
Maybe there’s a couple of sensible ideas in the approx 5000 replies your about to get, all recommending the calibre the poster has themselves….and a few from people just wanting to moan about the lead ban