It would not suprise me if at some point a Japanese official had a custom Arisaka sporter made. Many of the British gun makers were using imported rifle actions to build their custom Mausers on anyway, so why not do one on a Japanese action? That type 38 action looks like it would be good for building a short action sporter. Barrel threads are 1.025" 14tpi, very easy to cut. Walnut sporter stocks are still out there.