As horseman2 explains, a Seiko is a watch. Sako is a rifle made in Finland. My father, who came here in about 1957-58, was born in Finland as were my mother's parents. They spoke Finnish at home and it was my first spoken language.
My father's brother followed his brother by emigrating to Canada in the early 1970s. He was in his twenties then and I remember when we picked him up at the airport in Toronto. He had a long, sealed package with him. He had carried it with him aboard the plane from Finland. It was a rifle, a Sako, that he bought for hunting moose with my father in his new country of Canada.
When my father asked his brother how he he was able to carry it on board, my uncle replied in the only language he spoke that he tried to explain what was in the long box but was not understood. When he tried explaining by saying something similar to "Bang, bang" he was understood. Apparently, the sealed package remained in his possession during the flight across the ocean. My uncle had it with him when he disembarked and came through customs.
To be sure, times have changed since the early seventies, but the pronunciation of the name of the rifle manufacturer hasn't. While anglophones often alter how names are pronounced, the correct way to say Sako is close to Sucko, with a short "o", not a long one (as in O'Henry).