Everybody's bulk grade economy ammo is loaded differently than their better, more expensive lines ...
Usually, in the past, we'd only notice the ammo appeared "dirtier" when we'd order 15K-60K of this type of ammo for qualification, no matter the manufacturer. Then, we later started ordering the "standard" contract-type line in JHP, as the pricing was similar enough to make it worthwhile, so it could be used as both training & issue. Examples of this would be the Remington Express line, and the Winchester Subsonic & Personal Defense or USA lines.
This ammunition is still dirtier than the premium ammo produced by these same companies, but appears cleaner than their bulk grade ammo.
Something else we noticed was that no matter the manufacturer, or whether it was bulk FMJ or the slightly higher priced standard line of JHP, we experienced occasional failures to ignite with good hits on primers. One day I counted two out of something like three cases used, and it was a mix of two different manufacturers ... These things happen, and that's why we pay more for premium ammo when we can afford it.
At the moment we're stocked with a combination of Winchester standard contract & Personal Defense in one caliber, and Remington Express in two other calibers. Both seem equally accurate.
But we issue Ranger "T" Series ... and before we did that, I bought my own premium duty & off duty ammo ... generally Remington Golden Sabre, Winchester SXT or Speer Gold Dot ...