The story... I finished assembling my PA10 and got it to the range the first time in mid January. I brought Remington 150g CoreLokt .308 and Aguila 7.62x51 purchased from the local store and the ZQI 7.62x51 that I got from AIM Surplus for a smile-inducing $9.29 for 20 rounds. For the next trip, I reloaded the once-fired brass with a starting load of AR-COMP and 150g Hornady FMJ. The commercial .308 and the reloads ran perfectly - gun operated, no jams, rounds stripped from the mags, etc. The Aguila ran fairly well, though there were a couple of failures to feed and/or jams. The ZQI was a mess. Single shot only - the bolt wouldn't strip the second round from the magazine reliably. The rounds fired fine when they got into the chamber, but the gun wouldn't operate as a semi-auto - single shot only.
I went home, diagnosed the over-gassing with the NATO rounds, and swapped the fixed gas port for an adjustable model. It took a few rounds to get the gas adjusted on the third trip to the range, but the commercial .308, reloads, and Aguila NATO ran perfectly. Small groups, reliable operation. The ZQI? The 4" group at 100 yards became a 12 inch scatter plot and gas had to be adjusted for every other shot - two in a row max.
I pulled the bullets out of the 33 rounds left in my range bag and measured the powder charge. As this is NATO, the projectiles are sealed in the cases. Some of the projectiles pulled easily...others required both hands and a small dog to break loose. Here's the charge distribution per the Lee balance:
- Grains Number
43.0 - 2
43.1 - 1
43.2 - 0
43.3 - 2
43.4 - 6
43.5 - 6
43.6 - 6
43.7 - 4
43.8 - 1
43.9 - 4
44.0 - 1
44.1 - 2
44.2 - 1
In spite of the glowing YouTube video reviews of ZQI, I can't recommend the 7.62 NATO for gas operated guns.
edit...updated charge data after pulling a few more rounds.