I have a standard 16" barrel Stag Arms carbine. All original Stag parts built by Stag. It seems to have a lot of gas. Over the years I've added a Stag FA bolt carrier group and H2 buffer. It still seems to have harsher cycling than it should, even shooting .223 Remington ammo rather than 5.56 NATO. My PSA mid length carbines are very nice and mild in comparison. Any thoughts?