How much to increase the size of the gas port?

[Tim K]

Trying to get a barrel that was ported for suppressor only use to run without one.

Port was 0.069?. It would eject the case but not pick up the next round. I have 0.070? and 0.075? drills and can get 0.073?.

I don?t have any experience with how much difference to expect 0.001? to make. I ran the 0.070? drill through it. It went so easy it seems unlikely it?s enough to get it to run.

I love to hear from you guys with more experience.

[BPTactical]

What buffer are you running on it?

[Tim K]

Buffer alone weighs 3oz. H2?

JP Aluminum BCG.

[battlemidget]

Go big and put a suparms AGB on top?

[Hoser]

None of my experiences with aluminum and Ti carriers were good in the long run. Pretty cool for the first couple hundred rounds. Then the rifle quit running.

[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

[Tim K]

Well, 0.001” increase did nothing I could detect. I’m going to jump to 0.075 and be done with it.

I have one aluminum BCG. It gets used exclusively for the SAC for obvious reasons. To my surprise, it’s been trouble free for quite a few years. Not a lot of rounds on it (like 1K maybe) but it doesn’t even show wear yet. Only on a ridiculous gamer gun for sure.