New build AR15 pistol, 10 inch barrel.
All parts new. The rifle does not cycle all the time. I have to pull charging handle back to eject the fired round.
I pulled gas block off to inspect. Gas tube has normal size hole. The barrel seems to have a smaller hole. Is this normal? It seems to a gas problem. Rifle fires great but won’t eject or cycle.
Thanks in advance for any advise.

What ammo? What length gas? Will it lock back on an empty mag? Does bcg cycle at all? Yes gas block hole is larger than barrel port. Sounds under gassed

Need more details on parts, build, complete upper? Brands?

The gas port is supposed to be smaller than gas block hole. Does the gas block align properly. What buffer, ammo?

Check that the carrier key is properly torqued.

Check that the gas tube is not mounted upside down, and not obstructed.

Which indicates the bolt does cycle now and again. The interesting part is when it apparently does not - or - cycles so fast it doesn't even strip a round and just chambers the empty right back. Less likely.

Routine is to test with full power Nato if at all possible, not white box, one round in the mag, load and fire. If it won't cycle, note it, if it won't lock back, note it.

Jams are a little trickier, their are different things: won't extract, wont eject, won't feed and some combinations of two. I had one that wouldn't eject then double fed the new round and empty jamming. Cycle speed was too fast to even kick out the empty and took a H4 buffer to do it.

Which goes to what buffer? Action spring, issue or special. Then there is the buffer tube, a tight fit with no exhaust port to allow air to get pushed out while cycle causes stoppages. A1/A2 buttstocks with the hollow screw saw that one grounding the pad into mud, it would clog and it won't spit it out against your shoulder.

Should be enough to test during the next range session.