Yep, this is exactly the problem. However, confusion happens because there are two distinct problems, both with the same (or similar) solution:
The test is, to place a cartridge in the breech/chamber, and then tilt the barrel up. If the cartridge sticks, then there is a ridge there that needs grinding down (if the gun is new, send it back at this point). If the cartridge slides out with ease, but you still experience stuck cartridges after they've been fired, it's a polishing issue. From what I've gathered, the barrels ship with some parkerization or something inside the barrel, which causes the spent cartridge to stick. Solution for me was to get a barrel brush and wrap it in some steel wool, hook it up to a dowel and insert into a power drill. Run that in the chamber for a few minutes and then clean it up. Keep doing this after shooting the next couple times, and eventually the jams stop.
Last time I shot with low-brass (cheap CompX carts) I only had one stick out of 50, down from one every 5/6.