Actually, there are differences in pressures and performance for different bullets of the same weight. A 168gr Barnes TSX/TTSX has no lead but has 3 or 4 rings cut in the bullet to manage pressure and reduce fouling, as compared to a lead core hunting bullet as opposed to a match bullet. Differences in jacket thickness, alloys and design produce different ballistics, accuracy and behavior. Plated bullets, like Speer's DeepCurl have different characteristics than jacketed bullets like Speer's HotCor and different loads are recommended by the manufacturers. Also, different rifles perform differently with various bullets.
Accordingly, I have the manuals from all the manufacturers whose products I use...powder (Alliant, Vihtavuori, Hodgdon/IMR/Winchester), bullets (Speer, Sierra, Barnes, Nosler, Lapua and Hornady) and my old faithful, Lyman's (49th ed currently). I also check manufacturer websites for updates and notices. I recommend this...it has worked well for me though YMMV.
My goals are threefold:
1. the safest, most reliable ammunition I can produce
2. a custom load for each gun and application that I have in mind that offers best accuracy or terminal performance from each rifle
3. personal safety while hand loading and shooting
Much like shooting itself, these goals can be realized by a combination of the right training, the right knowledge base and the right attitude. I've been loading since 1978 with no incidents save for a few broken decapping pins and bent recapping assemblies from sizing/decapping the occasional Berdan-primed case that got mixed in with my surplus mil .30-06 and 7.62x51 brass (I usually inspect cases after I resize them as cracks and head separations sometimes happen as I work the brass).
FH