I need help with some barrel markings

[colocowboy01]

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?

[ldmaster]

The additional stampings are sometimes a barrel designation for a custom run. They use it to mark the special run barrels. I have one from a run for the dutch miliary that has three letters that were a contract designation that they had to put on the barrels per contract. I've only seen that stamp on one other barrel, and it was from Bravo Company, they would know what it means if it's their barrel.

[colocowboy01]

Thanks Idmaster. I will check with BCM to see if it is one of theirs.

[mutt]

High Pressure and Magnetic Particle tested? BCM barrels tend to have that marking.

[gcrookston]

High Pressure and Magnetic Particle tested? BCM barrels tend to have that marking.

--- correct. You'll find 'HPMP' on higher grade barrels, such as mfg'd by Sabre (now defunct), Colt and even Stag Arms.

[ray1970]

Are you sure it is "HP" and not "HF"? The HF could be hammer forged. The MP, like others have stated, is Mag Particle.