Rory Gallagher’s Martin Medium Gauge Acoustic Guitar Stringsaccess_time First seen circa 1991
According to an interview Rory gave in 1991, he used Martin medium gauge strings on his acoustic guitars.
Acoustic would be medium gauge Martin strings.guitar for the practicing musician, August 1991 issue.
If you’re looking to buy a set for yourself, basically look for any decent .013 – .056 strings. If you want strictly Martin, go for their Martin MSP4200 SP Phosphor Bronze set.