Really? The load data in all of my manuals is set in stone and is now a recipe instead of a "Guideline" . I cannot substitute a Federal primer if my manual listed a Rem? I cannot use data for a bullet of same weight of similar construction (substitution)? I cannot use my firearm, I must use the one used in the manual? I must use the same lot number of powder, primers and brass?

Now that that is done, Show where in the loading manuals that "clearly state that you should not substitute components". Mine say that IF I substitute any component I should start low and work back up, but NONE say that I cannot substitute components of similar design, weight and construction.

Now to the OP, do not use these primers in your 270. This is not a component substitution, they are simply the wrong primers and will give you issues you do not need.