Falling upon tougher times in the late 1950s, the Westshoremen merged with the Bonnie Scots from Millersburg, Pennsylvania, a merger that created one of Pennsylvania's top Class B senior corps. The enlarged group was strong enough to make it to DCA Finals in 1967 under the Bonnie Scots identity. It was during this period that the corps founded and hosted the annual "Review of the Corps" in Carlisle, Pennsylvania, an annual gathering that ran successfully until 1989.

The corps reorganized as the Westshoremen, Inc. in 1974 and began the long climb back into DCA contention. They took 11th place in 1976, and finally cracked the top ten in 1977, a position they were to hold until 1983. 1982 was the corps’ most successful season, as they won several contests and placed second at DCA Finals. After a fourth-place finish in 1983 and a change in management, the corps went through another rebuilding period, making it back into top ten status in 1988, where it stayed until 1997. Two long-time leaders during this period were Larry Hershman (74-83) and Dan Bowman (84-92).

A trying period in the early 1990s led to new leadership in 1995, aggressive recruitment of new members, and a jump in DCA standing from tenth in 1994 to second in 1995, a year in which they captured the high percussion trophy as well. This set the stage for the incredible 1996 season: the corps became the DCA world champions, a title win made even more special because of the corps’s remarkable comeback from a 0.9 Prelim deficit to narrowly edge out a great Caballeros corps. The Westshoremen also performed an exhibition at DCI Semifinals that year.

After that championship season, many members left, and 1997 was a struggle. Based today in Harrisburg, the corps was inactive in 1998 and 2002. In that latter season, some Westshoremen members bolstered the New York Skyliners.