A03 of the Keystone 25 listed a TARGET weight of 1,340g complete unit, loaded. A04 physical build came in at 1,387g — 47g over TARGET, almost entirely in the clamshell spine hardware documented in the layout iteration note.
The question at A04 review was whether to fight the weight or accept it. We accepted it.
The 47g overage comes from the bridging extrusion that carries shear across the clamshell split line. Removing or lightening it would require either a design revision to the load path — which would push back the A04 build window by approximately three weeks — or accepting a structural weakness at the primary load axis, which isn't acceptable for the Keystone 25 brief.
We did evaluate a pocket machining option on the extrusion that would have recovered roughly 18g, adding ~£22 per unit to the machining cost and a further week of lead time. The recovered weight didn't justify either cost.
The weight claim moved from TARGET (1,340g) to VERIFIED (1,387g). The TARGET column now shows 1,300g as the next-revision objective — achievable if we move the extrusion to a lighter alloy section in B01, which is already under review.
The evidence pack for A04 includes the physical weight record (three measurements, averaged) and the rationale for accepting the overage rather than reworking the geometry.
Downgrading a claim feels like a regression. It isn't. A system that accurately describes what it does is more useful to an evaluator than one that carries optimistic numbers forward from the design stage. The A04 weight is what it is. The next revision target is documented. The reasoning is on file.
That's the standard. It applies upward and downward.
RELATED PROGRAMME
Keystone 25 →