I got my first own deer rifle when I was 11 and it was my Remington 700 ADL .270 Winchester. Since I've owned it, there has never been a factory round fired through it. My Dad started me out on 140gr Hornady SSTs and that's what I still use today. He never had much experience with .270s in the past but decided to go with the 140gr for a good weight between the 130s and 150s.
I debated switching bullets, but my rifle pushes the 140 SST at 3080fps with a good dose of IMR 4831 and it shows no signs of excessive pressure. With the .495 BC and high velocity, this lightweight rifle is deadly. The 150 SST has a .525 BC but with the loss in muzzle velocity, the downrange performance is nearly identical so I see no advantage in changing slugs.
Last year I shot a doe at 728yds with my .270 and it dropped her to the ground, then she crawled about 20yds or so before she expired. Shot placement was just behind the left shoulder and the slug excited just infront of the offside shoulder leaving a half inch diameter exit wound. I didn't hit any bone besides ribs, but the bullet still managed to open at the low velocity and do its job. This is my longest kill to date and I was very pleased with it. The 140gr SST did its job and the buddies I was with were surprised by the .270s long range performance. They weren't expecting this from a standard deer rifle and a cartridge that is not used or known for its long range capabilities. There may be better options out there, but for what I do, I can't see using anything else. From dispatching deer at 15 yards in the brush, to dropping does at 700yds in the fields, the 140 SST fits the bill!