Methods, systems, and devices for wireless communications are described. In some systems, base stations and user equipment (UEs) may use beamforming for transmitting random access channel (RACH) messages. A UE may transmit multiple RACH preamble messages (e.g., within a random access response (RAR) window) to initiate a RACH procedure. The UE may transmit the RACH preamble messages in transmission opportunities corresponding to reference signals received from the base station. In some cases, the UE may determine the number of RACH preamble messages to transmit within the RAR window based on an ability of the UE to simultaneously monitor for a RAR message in response to each of the transmitted messages. In other cases, the UE may transmit an indication of UE capabilities to the base station. The base station may determine a RACH resource configuration for the UE based on the capabilities and may indicate the configuration to the UE.