Why logistics commonality is not always a quick fix

Why is common logistics across all services not always possible, particularly for land and naval guns?

Commonality can help, though naval and land-gun requirements may diverge enough that combining them saves little or creates new problems.

Cross-service standardization offers no automatic logistics solution. Land guns were traditionally much smaller than naval guns, so combining the systems was not always sensible even where some commonality was possible. A large empire could also sustain separate production streams at sufficient scale, reducing the benefit of standardization. Commonality helps only when service requirements and production scale make it worthwhile.