24.594 inches = *650 mm*. THAT's the reason for the difference.
Incidentally, 650 mm is arguably the standard scale length for classical guitar, so if you want to really talk vintage….
Sorry, but not exactly:
24.594 in x 25.4 = 624.6876 mm
650mm / 25.4 = 25.5905511811 in
Indeed. While I agree many acoustic guitars have a scale length of "about" 25.5", the LP design, and the 594 that, uh,
emulates it, is the other side of the 25" mark. A strat (and the Silver Sky, accordingly) has a scale length of nominally 25.5".
I have two 594s, both SH: a DC and a SC. They play absolutely divinely, IMHO. The neck carve probably a bigger feel factor than the scale length.
Which reminds me: at some point, maybe 10 years ago, or maybe about the time I got my first PRS (nine years ago, now), I learned that guitars had different scale lengths. I had, up until that day, assumed all "regular" guitars had the same scale length. ("I was today years old when I found out that...").
I owned a Les Paul and a Strat at the time (amongst others), and had never noticed. Yeah, I knew basses were different, but had no clue that guitars, electric and acoustic, had varying scale lengths.
That's perhaps a big part of why I'm scale-length agnostic. They all seem OK to me.