I have found that the longest that will fit in a ammo box without any problems
is the longest OAL allowed in my 270 and 30-06 paper ammo boxes.
I don't know if this will work with your caliber, since I don't own one....
and then the is always the internet OAL data to look up.
Old timers "Smoked" their loads to get a OAL then backed it off a touch.
However, never use this type of ammo in any other rifle, due to
pressure problems or stuck bullets that may result, if not fired
and the tried to extract.