[mrerick]

have you removed the extractor (it's an easy job, just drift out the pin - carefully holding it in place so that you don't lose the extractor spring)? Also, checked the spring well for dirt and cleaned it in that area?

I can't comment on Remington 9mm UMC ammo because I don't use it, but in addition to any quality concerns, it might just be the powder that they use and it's burn rate.

Manufacturers will use their own group's components when making ammunition. For example, it's very likely that Winchester White Box 9mm ammo is loaded with their W231 powder.

While Barnes (bullets) is part of the Remington Outdoor Company (renamed from the Cerberus Capital Management owned Freedom Group conglomerate during bankruptcy proceedings a few years ago) but I don't see one of the powder manufacturers is in the group. It's very possible that they source powder from multiple places, but hard to know for sure. Their annual report confirms that they source gunpowder from a number of companies.