These lower receivers are in an AR-15 platform and won't be compatible with larger cartridges like .308. AR-15 Lower receivers are great platforms for smaller rifle cartridges like: 5.56x .223,x 7.62x39, 300 Blackout, .458 SOCOM, .450 Bushmaster, .350 Legend, 6.5 Grendel, 6mm ARC, 12.7x42, and 22LR.
LR-308 Lower Receivers (Sometimes called AR-10s) are great platforms designed to work with long cartridges like .308 Winchester and 6.5 Creedmoor.