07-17-2017, 04:00 AM
Sounds like the upper was over gassed while using the lighter buffer and carbine spring. Is that an 18" barrel with mid length gas system?
If you try the lower with the carbine buffer tube, carbine length spring you might try a H-2 buffer which is heavier.
If you try the lower with the carbine buffer tube, carbine length spring you might try a H-2 buffer which is heavier.