I've got a bunch of 12.5" barrels, this is my favorite AR length by a long shot. This is a custom drilled gas port for 100% suppressed use, no steel cased ammo and no underpowered stuff. It won't cycle at all without the can. However, because the port is sized appropriately for my use, it's a very light recoiling setup that reduces gas to the face big time and it's one of my favorite to just blast with. Accurate barrel too.
This is about the 3rd or 4th paint job on this gun once I get below 50% remaining paint coverage I hit it again 😄