Listen Mossy, I think a few people is taking this too far. I mean big bold letters like YES. Come on. The two powders are almost always within 1 grain of max load from each other in standard rounds like your 270. Take the speer manual, and barnes. With some bullets, they are exact, and some are within a grain. As the case opens up a tad when the case gets larger or you get to compressed loads. If you work up your load from which ever powder you got, you will see the pressure signs. And I know you know how to look for them.

I think people gets too caught in the manuals. Its a guide and results that a company got with a certain barrel. Not your barrel. Like my Krieger barrel in my 300RUM, will show pressure signs with max loads in some manuals but not with my factory barrel. You will even see deviations between editions of manuals. On edition will show one load being safe, and another different.

No they are not perfectly interchangable but they are close enough you can build up a load from starting load and note pressure signs. Especially a 270win.