This chapter details two types of drumbeats used by drummers when playing irregular-meter grooves based on large repeating spans (ten or more beats or pulses). The types – punctuated and split – differ with regard to the subdivision of the repeating cycle. In punctuated irregular grooves an established meter is interrupted at regular intervals by isolated measures in another meter. In split irregular grooves, the cycle is divided into two or more subsections of approximately balanced lengths. The drums play a critical role in decoding these subdivision patterns. Many irregular-meter drumbeats can be related directly to the familiar common-time backbeat, and the ways that an irregular-meter drumbeat diverges from that regular-meter archetype provide a ready guide for metric analysis. At deeper metric levels, drumming conventions such as fills serve as structural landmarks. The theory of punctuated and split metric structures demonstrates the centrality of drum-kit syntax to the performance, perception, and analysis of metrically irregular rock music.