Hey everyone, have a little bit of a problem with one of my newer builds. I took it to the range to run some rounds through it and saw it was undergassed. Brass was ejecting consistently to my 4-5 oclock and the bolt carrier would sometimes not lock open after last round as well as fail to reset the trigger. I'm assuming those last two symptoms were caused by the bc not traveling far back enough.

So how do I go about fixing it?

I know people usually look at buffer weights, I'm already running a 3.3 oz carbine buffer and for what it's worth I'm running an armaspec stealth recoil spring. Has anyone had any troubles with the armaspec having a break in period or anything?

Gas block should be aligned, gas lock has been pinned to the barrel and index marks match up correctly. Yes the gas lock also had set screws installed.

I have heard about over oiling to cause malfunctions and I do have to say my rifle was thoroughly oiled, possibly too much. It was about 20 degrees at the range at the time of the firing.

Sorry bout the long text but I appreciate all the insight.

Ammo : Remington umc 55gr fmj
Lube: Hoppes #9 gun oil
Just finished up the build, this was my first trip out with it

Wipe all visible oil off everywhere and try again, that’s what I would do.

And try other ammo I had on hand too.

If you have a standard spring I’d bring it to the range to swap out if wiping the oil off didn’t work.

And I’d bring a lighter buffer if I had one handy.

Ejecting at 4-5 o'clock at 20 degrees is equal to 2-3 o'clock at 90 degrees, IME. Cold weather will slow down the cycle. If a rifle is barely cycling in hot temperatures it will short stroke when it's freezing outside.
Short stroking is usually caused by too much friction on the BCG or too little gas. Below are some thing to check and possible areas that could be improved upon to get the carrier to travel with more force/speed. Since you are barely short stroking it may only take a small adjustment here or there to relieve friction?
I'm not familiar with your buffer spring but swapping it out for a standard carbine spring would be the first thing I would experiment with. Maybe your spring system doesn't like cold weather? If you want to stick with the same spring you can drop the buffer weight down or find something in the list below that can be improved upon.

Possible reasons for too little gas=
Too small of a gas port.
Gas leaking at the gas block/barrel connection.
Gas leaking at the gas block/gas tube connection.
Loose gas key.
Gas block not aligned with the gas port.

Possible reasons of added friction=
Rough/tight chamber - stuck cases.
Buffer or buffer spring too heavy.
bolt/barrel extension not timed correctly.
Gas key/gas tube not aligned correctly.
Overly tight gas rings.
Receiver extension not aligned with the receiver.
Receiver misshapen.
Rough surface inside receiver or extension.
Foreign material loose in the carriers path.
Friction from the mag or the next round in the mag on the carrier.

16" Ballistic Advantage hanson profile in .223 wylde. Mags were just gen 3 pmags

Start with the easy stuff.

The gas block alignment would be top of the list, but the gas block is pinned, so start with other possibilities, eliminating issues one by one. GB may come back as a possible issue, but check the easier stuff first.

My two cents...