Buffer tube adapter

Hey all,
I’ve got a MP7 V4 and will be putting a few upgrades (spring, o-ring, metal gears etc.) to make it a little punchier, but I’m keen to swap out (or mod) the buttstock, as it’s got a pretty flimsy connection between the two slide rails and the butt itself.
Anyone seen any buffer tube adapters so I can fit a different buttstock to the MP7? I’ve had a look but can’t find anything.
The rear end of the receiver looks almost like a Nerf configuration.