A combustor-to-transition seal (301) includes a spring clip assembly (322, 422, 522) and a first spring metal ring (340, 441) or a ring assembly (440,540) that includes the first spring metal ring (441) and a second spring metal ring (442). Such combustor-to-transition seal (301) provides a first seal (321) and a second seal (331, 531) when at a junction of a combustor (108, 308, 508) and a transition (114, 314, 514). In an embodiment, the first spring metal ring (340) has a plurality of apertures (342) through the ring (340) that provide effusion cooling of the ring (340). The plurality of apertures (342) regulates a flow of cooling fluid to maintain an acceptable temperature of the ring (340). In an alternative embodiment, the second spring metal ring (442) has grooves (446) that regulate a flow of cooling fluid to maintain an acceptable temperature of the ring assembly (440).