For a while some sporting clays shooters were using fast 12 gauge Longshot loads at our range. They were exceedingly loud. Burning nearly 40 grains of powder turns up the volume. You would not have to ask what they were shooting. Eventually, people stopped using those loads. Probably, their scores were no better than with milder loads.

About 15 grains Longshot in 28 gauge gives a mild report, so the amount of powder probably makes the difference.