[archy]

As the Liberator pistol of WW2 fame demonstrated, all that one needs is a firearm that can fire reliably ONCE, and that can lead to the acquisition of additional (and far higher quality) firearms and ammunition

But a little redundancy is nice. Double-barrelled designs are available, or one can simply build a pair of single shot wapons and carry one in each hand.

[Squantos]

Also lots go EDM and CNC programs laying about. Bench top 5 axis solutions abound......