Skotia

If I remember correctly AAC is a subsidiary of Remington; and, as you recall, PTS released the AAC Blackout 51T flashhiders and AAC M4-2000 licensed (if I recall correctly) from AAC. Thus it's not entirely true that PTS had no dealings with Remington. After looking at the prices for the RIS foregrip, however, I doubt that I would be interested in such a product anymore...

DBoys 450rounds HiCap fits if you force it in; does not engage the mag catch; feeding is sporadic.

Those photos are of Mers (from AAC) holding the ACR (probably, in this case, chambered in their prized 300BLK round) in the recent SHOTshow just over a week ago. I would seriously doubt the speculation that the five-sided handguard would not be produced given their recent portrayal in SHOT. P.S. The five-sided handguard is still part of Remington's spec sheet. If Remington produces it, Magpul PTS will be likely to produce it as well.