The three Graflex shutters I measured over weekend (above posts) are quite accurate.

This morning I measure a new-in-box Prontor SVS , box says 1957, the shutter is obviously never used.

{ speed, ideal, measured millisecond}
{1/1, 1000, 1600+}, {1/2, 500, 700}, {1/5, 200, 220}, {1/10, 100, 250},
{1/25, 40, 76}, {1/50, 20, 30~50}, {1/100, 10, 12~15}, {1/300, 3, 5~7}

This shutter is slow, and erratic on the 1/50th, note how the 1/10 speed is slower than 1/5
What should be done with it?
I might try - warm it up to 45 C for a few hours, fire it 100 times, then re-measure it ??