In my limited experience, I have found that different powders, even with the same bullets, come together at very different velocities. For example, I have three different powders, with one bullet, that shoot to regulation at Xfps, X + 125fps and x + 190fps.

If I were to load powder one to the velocity of powder two's load it would cross. Likewise powder one or two to powder three's velocity.

Throw in different bullets and the issue is compounded.

Changing trigger pulls won't effect regulation. It is extremely unlikely that you changed the weight or balance of the rifle enough with pad or comb work to throw the rifle out of regulation.

JPK