M4 M16 Adjustable Lipo Carbon Stock

Hello, I designed this for a friend of mine AR-15 to make it lighter since is very long and heavy. I used a 32mm carbon/kevlar tube, so is enough for a lipo stick in the buffer tube and a mosfet in the stock space or viceversa.
It's adjustable in 2 positions, I suggest to print it at least in PETG, ASA, NYLON, ABS to make it strong. Print the buttstock in tpu, at least 95A or stiffer.
All you need is an m5 bolt for the receiver connection and an m4 bolt-nut + D5.5-7mm spring for the pin then