I hear they work well in a glock 27 but in my full size M&P the 40's jammed every round... Was quite disappointed. I might do like others have said and get a cheap revolver. 357 or 44 mag and just use that when im out and about on my property.Ingenious... I've thought about developing rounds like that if I needed to.
Or, you could just use the CCI .45ACP shotshell... they've worked for me.
I've never tried the .40S&W version, never found them.