Ken Waters did quite a bit of work with the 405 in his Pet Loads book.
The SAAMI drawing for the 405 looks like it would not be very conducive to cast bullet use. No real throat to speak of, just a 45 deg. bevel from the case mouth to the bore. How are those Rugers throated? Have you guys gotten good performance from them with cast?
Oh, remember it looks just like a 40-70 straight. Loads for that will work too.