I have seen them with a Rem Varmint/Sendero jammed in, but it definitely was overstuffed.
A #5 is where that stock maxxes out. You might push that a smidge, but if you do, keep an eye on shank length.
#5 is your answer, within conventional bounds.
"What we obtain too cheap, we esteem too lightly: it is dearness only that gives every thing its value. Heaven knows how to put a proper price upon its goods; and it would be strange indeed if so celestial an article as freedom should not be highly rated." Thomas Paine
