How much to increase the size of the gas port?

[zimagold]

I will second Hosers opinion and say none of my friends that tried lightweight bolt carriers still use them. Too many reliability issues down the road.

I normally go one numbered drill bit at a time. Recent example is a 16? mid length that arrived with a 0.070? gas port. 0.076? ran well clean with H buffer and standard spring, but had issues once it got dirty with weak ammo. 0.081? would run up to an H3 with Springco Blue dirty with minimal lube. I stopped there and use an H2 to have some margin for colder weather.

Edit:

Carbine = 3.0 oz
H = 3.8 oz
H2 = 4.5 oz
Rifle = 5.2 oz
H3 = 5.3 oz