Nice bass. I thought you couldn't get custom neck sizes in 5-strings, though. What's your secret?
I LOVE the sound of L2500s but can't get use to the string spacing…. It's got to be at least 18mm for me, alas.
I played an M2500 in the shop last week and was totally impressed with the playability and B string, but <sigh> I just can't do the string spacing (and I prefer the L2000 electronics).
Thank you, JES, there is no secret, the 1-15/16th was the factory nut width on L-2500 (regular) and L-2500 Custom in 1996 and early 1997. I wish you to find one from this period.
This one is dated Jan 1997. A few months later, G&L trimmed the nut to 1-13/16th (when they changed the headstock from 4+1 to 3+2 with a few other things, by mid- or late 1997), though it's been again narrowed to 1-3/4 since then (#10 neck).
However the string spacing at the bridge is 17mm (68 mm from B to G, center to center), I believe it's still the same as of now.
I had a M-2500 until last year, I had no problem with the #10 neck that I liked much, the problem for me was the tone. I prefer that L-2500 and I am now familiar with the wider nut. I am gathering information on the special coil tapping electronics that produces the particular tone of that bass and will let you and others here know soon.

