>>64073552
Not that guy, but you use an AR-15 assembled bolt, barrel with extension, firing pin, and magazine spring (shortened). Most of the rest is printed and then you need some springs, 3mm rod, and M5 nuts and bolts. It's a neat design but it makes way too many compromises in the name of looking like a Mauser. You can read my assessment of it here: >>64048276 >>64048469

You can definitely print it as designed, make it work, and fire it occasionally, but it will always be a curiosity and not a reliable workhorse, at least without a significant redesign in the components at the back of the bolt (not shown in that picture).