.17 Remington. Yes, it is legal in my state. I wouldn't go that small though.

Many calibers will do the job, but I am a stickler for a .270. My son took his first deer with a .223 but it was a perfect shot. Not much blood though.

Zink... No problem buddy.. I'm not trying to start a pissing contest.. However, my point was that the 7mm RM ( or whichever 7mm mag you were talking about) is not unique among centerfire cartridges as far how far its bullets travel... Many chamberings from .22 centerfires through elephant guns could POTENTIALLY penetrate a deer and kill something or someone a mile or more away, including your 30-30..

Another good reason to make sure we have a safe background for all of our shots..

It's all been mentioned already. Any rifle smaller than a .243, any buckshot load, or any bullet that's constructed in a way so that it's designed for larger animals.

I would not choose any cartridges for which a reasonable variety of quality factory ammo was no longer available. I would not choose any true magnum that are more suited for the big critters. I would not go for the obscure such as the 308 Norma Mag., Warbird, or 30/378, etc. I would not go below a 25 cal. For me the minimim for deer is the 6 mm Rem. or 243 Win. No 22 cal. stuff for me. I am pretty much stuck on 30 cal., proven, Plain-Jane stuff for deer - 30.06 Spr., 308 Win., and 300 Win.

Anything larger that a .243 would be good for me. A .223 is far too small for me, it could work for some smaller deer in Texas but Northern Deer I wouldn't even think about it. I'm sure a .243 would be sufficent enough as well, but it is still to small in my book. I shoot a .270 and a 30-30 and quite happy with how both perform.

Considering that the Inuit use .223's for Polar bear, Grizzly, Moose, and Caribou I'm sure it will work on those northern deer as well.

Yeah, but they typically take head or neck shots. Most people in the lower 48 shoot deer in the body. I don't care for any caliber where the weight of the bullets drop significantly below 100 grains for deer or larger sized game. That makes the .243 my low end limit for deer.

what's a magnesium shooter?

.270 Win...........
Its completely ruined my blood trailing skills, it just kills the damn deer too fast......