TBAC tested it directly on their standard 5.56-16AR host (Daniel Defense 16″ AR-15 shooting 5.56 M193), which matches your query exactly. The data comes from their consolidated results page you linked (which combines .223-caliber, .280-caliber, and .30-caliber suppressors all tested on the same host for fair comparison).

Key Shooter’s Ear Metrics for the Jackalope 280 (.280 version)

• SE dBA (A-weighted, the main suppression rating most people use for ear-level quietness): 138.26 dBA
• SE dB (unweighted peak): 147.56 dB
• SE Imp dB*ms (impulse): 127.28 dB*ms
• SE Leq dBA (equivalent continuous level): 127.47 dBA
• Weight (tested config): 15.7 oz
• Length: 7.88 in
• Max diameter: 1.48 in
• Volume: 13.55 cu in

Lower numbers = quieter. For reference, an unsuppressed 16″ 5.56 AR is typically ~156–167 dBA at the ear on the same rig.

How It Stands Up Against the Other ~106 Suppressors Tested on the Same Host

The manufacturer (W.T.F. Silencers) directly analyzed the full consolidated dataset and states the Jackalope 280 ranks #3 at the shooter’s ear when sorted by the combination of SE dBA + SE impulse metrics (the two stats most relevant for perceived ear-level sound and hearing safety).

• It beats the vast majority of both dedicated .223/5.56 suppressors and larger-bore .30-cal suppressors tested on the identical 16″ AR host.
• It outperforms the .30-cal version of the same Jackalope suppressor (SE dBA 139.39) and crushes the dedicated .224/.223 version of the Jackalope (SE dBA 141.00).
• Top-tier dedicated 5.56 cans (e.g., SilencerCo Velos LBP 5.56, which placed very high in separate reports) are in the same ~138 dBA ballpark, but the Jackalope 280 achieves this as a lightweight, multi-caliber (.280/7mm bore) HUB-mount can — not a dedicated small-bore design.

In short: It is one of the quietest options overall at the shooter’s ear on a 16″ 5.56 AR, even though it’s a larger-bore suppressor. This makes it a strong all-around performer if you want one can that also works well on 7mm/.280 or .30-cal rifles. The full raw tables and graphs are on the TBAC page you linked (search for “Jackalope” or “.280” in the 5.56-16AR sections).