Time series of the total γ-ray flux within 100 kpc from the cluster centre, F_γ, over time. Point-mass γ-ray fluxes for all cool-core clusters with 6 × 10¹⁴ M_⊙ < M₂₀₀ < 10¹⁵ M_⊙ from Ackermann et al. (2014) are shown as vertical lines for comparison. A self-regulating CR-dominated jet produces a γ-ray emission that exceeds observational limits, while small fractions of CR in the jet are compatible observational constraints.