(snip)On deer at very close range the same might be true on deer when using the 170 gr bullets, I would hesitate to use 170 gr on small deer at short distances, 170 was made for elk and bear, not that it cant kill a deer, just more than what you need.
The 170 grain bullets are more than you need for deer, but 170 grain flatpoint bullets made by most manufacturers are designed to expand very well at 30-30 velocities. The last deer I saw shot with a 30-30 was shot with 170 grain Federal factory loads, and it was a spike blacktail. It was so small, I was able to carry it out on my back a distance of 6 miles without help, and without putting it down. The 170 grain flatpoint broke a rib at the rear of the left chest going in, made a royal green mess of the deer's last few meals on the way through, exited just behind the right foreleg, entered the right foreleg, and was found under the skin at the "elbow" joint. It was expanded to .56", and it weighed 138 grains. That's the only 170 grain bullet I've seen recovered from a deer, but all wound tracks showed signs of bullet expansion.
As for not using the 170 at short range, well, short range is where all bullets are most likely to expand the most, so I'm not sure if I'm understanding you here. The same goes for 180 grain 30-06/308 loads not expanding "at distances up to 100 yards." Perhaps you've seen some bullets fragmenting at close range, and tiny exit holes left by a single fragment are giving you the impression that the bullet didn't expand. You must have recovered all of the game, in order to determine that the bullet exited, so I was wondering what sort of internal damage you saw.
The 30-30 should have ample velocity to expand any bullet made for it out to at least 200 yards, except for hard-cast lead. Likewise, if you're using a .308" bullet that's designed to expand at all, the .308 Winchester and the .30-06 Springfield produce plenty of velocity to do the job, even out to 400 yards and more, depending on the specific bullet used. There is some chance that you simply got hold of some defective bullets or loads, if there was really no expansion at all.
Deer don't open up a bullet as far, or stop it as often, as really big game tends to, but the bullet does almost always expand some. I started hunting with a .308 caliber model 88, and my dad always stoked it with 180 grain bullets, and he always used 170 grain bullets in his 30-30, and I don't remember any problems with either (other than the recoil of that 88 against my tender young shoulder).