My quoted post doesnt necessarily have anything to do with shot-spotting, its about whether actual hit rates are better, the same or worse due to increasing recoil. And, you may be right, but its all hot air (from both me and you and anyone else) until its data we can all see…so why not test it?
Also, Holy hell, we’re talking about 40 rounds of ammo—1 box each in 2 cartridges, one being a 223! Do you really think thats excessive? This is a group of people that obsess about guns and shooting year round, many of whom shoot hundreds if not thousands of rounds a year practicing. Frankly, if 40 rounds in a practice session to see what they are actually capable of doing with 2 of their hunting rifles is too much for someone, that is perhaps the best reason yet to use a 223 thats cheap to practice with, and NOT use a big gun.
If its too much for anyones attention span, wallet, jois de vivre, or jus de vache, shoot the 2nd string only, 25-second par time, and omit either one of the sitting positions or the prone position, whichever you use least when hunting, and then repeat the drill for the 3 positions with one shot each. That’ll give you one 3-round group on each circle—two cold bore shots and one follow-up shot from each position, for 9 shots total. Repeat for the other gun. We all know 3 data points is less certain than 5 or 10, but it’s better than zero data points.