My grandfather, August Nilsson, served in the military in Sweden. He was born 12 Jul 1877 in Ösby, Örebro, Sweden. He was son of Nils Svensson and Sissa Perssdotter.
I'm told that when he was in the military, he took the last name Hallin. He immigrated to the US in about 1900.
I am looking to find any military records and hopefully to also understand why he chose the surname Hallin.
Any suggestions of where to look?