Has any one used the magpul detachable box magazine kit? I was wondering if it will fit the ergo stock as well. The description says it's a replacement for factory bottom metal. I'm conflicted I want the xlr chassis but the magpul stock is a good deal. I know I should just get the xlr chassis but I decided to get my little brother his first rifle. Mainly I want the magazine capability. If the kit will fit the houge overmold stock I can just get that and save for the xlr chassis.