**You'll 100% get this while going for other specific achievements in these game modes like: The Line Them Up achievement in Gears 5 worth 57 pointsDefeat 10 different opponents in a Free For All Match The Paydirt achievement in Gears 5 worth 21 pointsScore a Touchdown with the Flag in GridIron The Close Call achievement in Gears 5 worth 63 pointsWin a Match of Arcade Blitz where the opposition team is within 25 points of winning
However, (for those who want just this achievement and not the others for some strange reason) these can be done in public matches or privately with a friend (or second controller). The fastest matches are as follows:
Arcade Blitz: Set up a private match with a second controller (or bots) for 50 points.
Free For All: Set up a private match with a second controller (or bots) for 10 kills.
Gridiron: Set up a private match with a second controller (or bots) for 13 points. I didn't notice anywhere to lower the point amount. You get 2 points per touchdown (carrying flag to the zone), so you will need to play 7 rounds to win. This took the longest.
You need to complete them, not win, so you will get this after 3 matches.