I guess I don't see why anyone would want to load 40 S&W below the manufacturer's minimum load...? Primers are, for the most part, the most elusive component to obtain, now-a-days.

With 7K grains per pound, that additional (I shudder to use the term "extra"!) 0.5gr means you'll only expect to get 1,500+ bullets per lb.

If the question is really "Can I safely download a lead 180gr 40 S&W to well under 800 fps?", my 1st tendency would be to ask "But, why?".

Looking for a reload that won't reliably work the action or a squib?

Cheers!