After some research HPD refusing AR pistols registration is not because of the definition of semiautomatic, detachable or bolt action. HRS 134-8(c) states the manufacture, possession, sale, barter, trade, gift, transfer, or acquisition of detachable ammunition magazines with a capacity in excess of ten rounds which are designed for or capable of use with a pistol is prohibited. If HPD allows bullet or mag buttons then they cannot allow 30 round AR mags. This situation is avoided with a welded 10 round mag.
Both Dark Storm Industries and JC Arms make an AR lower with a pinned mag and they do not mill a hole for the mag release. Although not welded this should satisfy HPD requirements.
It's better to have government require all AR pistols to have a fixed mag rather than banning all AR mags with a capacity of greater than 10 rounds.