Relining capacity depends on throughput

Could a plant able to rebarrel a 16.5-inch/45 gun also reline a 15-inch/50?

Yes, but the longer gun would need attention more often. Plant throughput and the circulation of replacement linings would become the limiting problems.

A plant capable of handling a larger-bore gun could also accommodate the proposed smaller-bore, longer weapon. The problem is how often that weapon needs attention: the comparison suggests a difference of potentially about 200 rounds between the shorter and longer designs. Faster wear increases the plant's workload even if the gun fits its equipment. Singapore could remove an old lining and install a replacement, but reconditioning still required shipment to Britain. A faster replacement cycle would therefore keep more linings moving through the transport and repair system.