I don't know that there was ever an aluminum bolt upgrade.
My brother and I have been looking at making bolts out of Duravar. It's slipperier than delrin and doesn't swell when oiled. I need a bit more tooling for my lathe first.
Huge obnoxious sig line!!!
" dude this hk sticker made my gun shoot like 26 bps it was teh shizz" :dodgy:
"I was an instant genious when i started paintball" :dodgy: