Just keep hunting monsters. You get really weird monster bones near the end.
You get a large monster bone from the large monsters like the kut-ku.
4*+ Elder quests. If I recall correctly, the Green Plesioth awarded Monster Bone+.
You can get them by killing monsters with shells in the dessert.
Kill the things with spicky tails in the desert
combine bone and machalite ore. :)
in the desert, look for a large monster with a spiked tail. kill these!!! ---- they are not hard and you can carve them twice.
You could just fight a monster from the Upper Rank missions in the Guild Hall.
You can get it from Giaprey's after the quest ends.Good Luck Finding it...CeroNueve09™
This isn't a question but a incomplete sentence, and there is no such item, bone, or weapon called big bone.
Most medium sized monsters drop them, but I think the best way is to kill apcerpos in the desert or volcano.
By hunting a khezu, rathalos, rathian etc... The first time I got any monster bone +, it was when I got 3 of them from one run of the 5* village quest "Small Shadow over the Swamp".
monster hunter wiki