Do you doubt that he actual has both cans to compare, or do you doubt his assessment of which of two cans he owns is quieter on a specific host.
"No replacement for displacement" was never true for cans, design and design tradeoffs make a big difference for individual performance attributes, and with new designs available using 3d printing now, it's even less true than it ever was, comparing old designs with some of the new ones. Even before recent advancements, performance on bolt guns could be improved with very high backpressure designs, which the Tiger is when on .223 (although it's actually fairly low backpressure on .22lr).