Taken from PTS GP N23. This barrel is tapered and needs a tapered ready upper receiver. It comes with barrel specific hop unit. You may have do some modifications to fit and or work. The gash out of the threads is from the removal of the pinned on flashhider. Still threads flashhiders, suppressors etc fine. Ccw threads. All sales final no refunds no returns PayPal ready no local pick-up shipping only buyer pays shipping and PayPal fees. Ask questions prior to purchase.