Bacteriophages are viruses that specifically infect bacteria. When a phage infects a bacterium, it attaches itself to the surface of the bacteria and injects its DNA into the intracellular space. The phage DNA hijacks the cellular machinery of the bacteria and forces it to produce phage proteins. Eventually, the bacteria cell bursts or lyses, releasing new phage. The bacteria act as a host for phage reproduction. The ability for a phage to infect multiple bacterial species is known as host range. In siphoviridae bacteriophages, host range is thought to primarily be determined by proteins at the tip of their tail fibers. These proteins act as anti-receptors to specific receptors on the surface of bacteria. In siphoviridae Gram-positive infecting phages, the genes that code these proteins are typically located between the tape measure protein gene and the endolysin gene. It is hypothesized that phages that have similar anti-receptor proteins will have similar host range. In this study, the host ranges of 12 BD1 bacteriophages were tested on 9 different Streptomyces species. In these 12 phages, the genes between the tape measure protein gene and endolysin gene were compared. The 12 phages had high levels of variability in these genes. Five genes in this region had unknown functions and were called position A, B, C, D, and E. Position A-E were BLASTed on NCBI and Phages-DB and their results were recorded. The functions of position A, C, and E remain unknown. The function of position D is most likely a minor tail protein. Position B had BLAST hits for a collagen-like protein and a putative tail fiber protein. Position B was inspected further, and it was found that it contained Gly-X-Y repeats in its amino acid sequence. Position B also had some conservation in its N-terminal amino acid sequence, specifically where the Gly-X-Y repeats were located. Position B had strong conservation in the C-terminal end of its amino acid sequence. Glycine repeats and conservation in the N and C-terminal end of the amino acid sequence are both common factors in known host specificity related genes. There appeared to be no correlation in conservation of position A-E and host range. It was concluded that no single gene can predict a phages host range, but the discovery of collagen repeats could be used as a landmark to find genes related to host surface receptors.