请教一下bcm upper

满地找牙

you mean complete upper. major difference is barrel and handguard style.

for beauty, pick the best looking and brand you like

for function and accuracy, pick the best barrel or the most suitable barrel for your need

for both, better build yourself.


most common 16" barrel, you want midlength gas, twist between 1:7 - 1:9



sorry no Chinese input here