would you shoot a whitetail deer or a mule deer with a 80 grain bullet or is it to lite? if so whats the max distance you would shoot?

Stick to the heavier bullets, distance is determined by how well you can shoot it.

In 243 I prefer the 100 gr bullets, but they are good for 300 yds or so. I just like to go with a heavy for caliber bullet in all smaller calibers.

http://www.udarrell.com/hunting_shooting_ballistics_frames.htm

Check out the above link for info on the .243. My personal favorite was a 90 grain nosler ballistic tip which I can't find anymore. I'm using my 30-06 and .44 this yearbut of all the guns I own and have taken deer with, nothing has ever taken deer down faster or caused more internal damagethan my A-bolt with a 90 grain BT.(OR BEEN MORE ACCURATE).243 gets a definite thumbs up from me, its like lightning on deer.

I usually prefer nothing less than a .270 when hunting deer sized game, but many people have had success with the 100 Gr .243 on deer and the like.

Although I don't use the 243 for deer, the 85 Grain Sierra BTHP is a good deer bullet and the only bullet under 90 grains that I would consider. However the Barnes bullets also work well as you can drop a weight or two because of their construction. The nosler BT is a good one.

I can recomend the 100gr sierra gameking, killed 17 straight whitetails with that bullet at 2850fps.

Can't beat that. I used to use the 100 grain Hornady RN. Not a great long range bullet but they performed well. That was in the slower twist 6MM Remington however.

I use the winchester balistic tips in 95 grain. Took my last buck at close to 400 yards. He was out in the open and I misjudged the distance and basically got lucky. The bullet worked to perfection. The shot was good and he didn't go very far at all. My 243 is a heavy barrel varmit gun set up to shoot.