The SPQR Stock for PTW , no need for modification , plug in and shoot! Thanks for your supporting , We won't let our PTW operators down. :)
Someone asks me about why name it SPQR ? the answer is quite simple, is the ROME republic(Senātus Populusque Rōmānus) The Roman Senate and People.
Long story short ,I was playing Total War II: Rome last year and impressed by the Roman legionnaire with their famous pilum (Similar like javelin) so i asked my RD to draw something it could match our BD556 set with the shape of the pilum and with gladius (maybe later ). In the end we rounded the wooden square part and combined with the spear knob and remain the body of steel in order to match the current 556 body to make sure operator will feel like throwing a javelin to the enemy.
You could literary throw it , HAO would thank you for purchase one more LOL.