Gun Modding (Buttstock Compartment)

Today, I am modifying my Crossman Storm XT to have a compartment in the buttstock. The Storm XT has a solid hardwood stock, so drilling into it will be a requirement. The plan is to create a small compartment behind the rubber buttstock pad, but not too big... I've got to make sure we don't compromise the integrity of the stock. I figure the extra space can be used for backup ammo, a cleaning kit or some other useful items. So, come with me as I make yet another modification to this pellet rifle