It depends what you want the ammo for ? If i presume your on a deer stalking forum for a reason. I personally tend to go for 140gn bullets with Viht N165, about 57gn does the job. But can cause carcass damage with expanding bullets, best avoid Noslor expanding type ballistic tip if you are planning on eating. 130 gn also work well, i have used speer 130, not so bad for damage, and accurate enough for 200+ yard shots. and the beauty of a 270, I have have never had a runner, (Im sure someone will tell you they shot a rabbit at 30 yards and it ran half a mile with a 270, I would suggest, suspect the smell of bull****) You can go as light as 110 , but dont bother, accuracy is poor, but crows do explode!
as far as accuracy goes, dont expect target like performance, most 270's are light and often short barrelled ( easy to carry) but if you shoot off a string of bullets, the barrel will get hot and your group will move about, so get it at about a 100y, let it get cold, fire 2, repeat a few times, as you are only going to shoot from a cold barrel, then dont clean the bore until you need to zero it, then clean before you zero it, not after, and you are ready to go, I have an old sauer, sporting barrel, I zero shot it yesterday, a string of 5 and it was creeping about 3 inches high, it will group under 2 inches at a 100, with bipod and bag, freehand more like 3 to 4, its more than enough.
good luck and welcome to the 270 club.