If I may do a slight threadjack, does anyone know the same info for the -SB? I've never been able to find a distribution on it, or even a mention in any fluff, just a record sheet.
The CGR-SB was described in
BattleTechnology, and canonized through getting a record sheet in an official publication that, unlike BattleTechnology, wasn't de-canonized since. It remains unclear if the record sheet means its BattleTechnology writeup should still be regarded as canon as well (probably not).
Anyways, the story according to BattleTechnology ran along these lines:
Tech-savvy Hat-in-the-Ring Battalion (aka HRB, a merc unit in Davion employ) captures two CGR-1A1s from Liao forces on Holt (though that is actually a Marik world...) and nobody wants to pilot them. So Stuart Bell, the HRB's chief Master Tech, devises a modification that downgrades the fusion engine and replaces the existing small lasers with large ones - because that way, he doesn't have to meddle with the targeting computer. Thus the -SB version was born, and apparently became a rather popular field refit for those who could afford it - at least that's implied from the fact that the CGR-SB variant itself has subvariants. It is called "Challenger", by the way.
(see also:
http://www.sarna.net/wiki/Charger#VariantsI've heard that the Challenger from the record sheets is different from the stats given in BattleTechnology, but haven't looked this up yet.