Of my three M&Ps (.45, .40, and 40C) my M&P45 has the heaviest trigger, in spite of installing an Apex trigger in it. In contrast, the stock trigger in my recent production M&P40, and the trigger in my first year production 40C are fantastic.

Does the M&P45 have an inherently worse (heavier) trigger pull than the .40S&W models?

My M&P40 and M&45 are both recent production and close to brand new, and yet the M&P45 trigger pull is much heavier, much less desireable.

The M&P40 trigger is stock and feels wonderful, as does my older 40C... but my M&P45 trigger sucks, in comparison.

Any thoughts on this?