Here in the UK we are only allowed to practice on military firing ranges and target clubs can usually get to use one only about once a month so I don't have the time to work up loads from scratch.
I have a Steyr Manlicher SSG with a 26" barrel in .308W. RWS factory loads jam the bolt so it is sensitive to high pressures. I would like to load 125grn Nosler Ballistic Tips or BlitzKings and also 150grn similar bullets.
I have done groups of just over 1" at 200 yrds with Norma 180grn factory loads.

I also have an FN Sauer in 270W that I would like to load 140grn BT bullets for. In the US the rifle might be called a Colt Sauer.

I have on order a Tikka Stainless Synthetic Varminter and would like to try both lightweight and heavier bullets in it. Ballistic tips again!

Do any of you have experience of loading for these rifles so that I have a starting point for to go from?

I have a variety of different brass for the .308 and .270 and can get Federal ammo in .223 locally. Will differing brass make a big difference to consistancy or should I go out and get a big batch of one brand of brass for each calibre?

I have a Nosler reloading manual from about 12 years back. Have things moved on much since then?

Lots of variables, I know, but I'm sure I am asking questions that a lot more would like answers to.