Abstract: A new and improved ram lock and blowout preventer are provided for locking a blowout preventer ram in any of a number of variable, adjustable sealing positions in a bore in the preventer. A ram carrier is mounted in a housing to move the ram to and from the sealing positions. The housing is provided with a tapered inner surface which selectively engages locking wedge members mounted with the ram carrier. A locking cone mounted with the ram carrier responds to fluid pressure during movement of the ram carrier to move the locking wedges into engagement with the tapered inner surface for locking purposes.