I have come across an AR barrel from a trade with the markings 5.56 1/7 HPMP. I understand the 5.56 (caliber) and the 1/7 (twist ratio) but can anyone help me with the HPMP? Who is the manufacture of this barrel?
I have come across an AR barrel from a trade with the markings 5.56 1/7 HPMP. I understand the 5.56 (caliber) and the 1/7 (twist ratio) but can anyone help me with the HPMP? Who is the manufacture of this barrel?