The formation of swirling vortex rings and their early time evolution, resulting from the controlled discharge of an incompressible, Newtonian fluid into a stationary equivalent fluid bulk, is explored for weak to moderate swirl number 0 ≤ S ≤ 1. We first investigated rings generated by idealised solid-body rotation simultaneously superposed onto a linear momentum discharge in two commonly encountered inlet conditions in practice using LES simulations. The results obtained reveal that, for S ≤ 0.5, the addition of swirl promotes the breakdown of the leading primary vortex ring structure, giving rise to the striking feature of significant negative azimuthal vorticity generation in the region surrounding the primary vortex ring core, whose strength scales with S². We subsequently evaluated the characteristics of swirling vortex rings generated in laboratory by a physical rotating tube using PIV. Experiments without linear discharge (tube rotation preparation stage without rings being produced) reveal the presence of an intriguing secondary flow pattern in the rotating tube, preventing attainment of a solid-body like swirl distribution. A key feature of the experimental work is that partially established vortex rings, produced with short tube rotation preparation time before a steady state condition is reached, show unique characteristics. Their creation, a short time after the onset of tube rotation: (i) facilitates more efficient delivery of swirl momentum to the vortex core area; (ii) maintains a low level of swirl in the ring bubble's central region which would otherwise promote the formation of opposite-signed vorticity and vortex breakdown.