During the 1970s and 1980s, the experimental particle physicists at large laboratories responded to the limited funding context of that time. Unlike the "big science" in the postwar decades, when funding for research appeared unlimited and many parameters grew exponentially, the even larger-scale "megascience" of the 1970s and on was shaped by competition for limited resources at host laboratories. Experimental programs increasingly took the form of long-lived (typically ten- to twenty-year) strings of related experiments, invisible institutions creating research traditions within the laboratory. Focusing on how a particular study of charmed particles (experiment E-516) at Fermi National Accelerator Laboratory gave rise to one of the laboratory's earliest experiment strings (E-516-691-769-791), we explore why such strings evolved and how they led to new research practices. Because these strings produced conflicts and ironies that threatened to undermine fundamental aspects of the research, the emergence of experiment strings can be viewed as a limiting process of large-scale research in the 1970s and 1980s.