I have found a gunsmith in the Louisville, Ky. area that solved my problem concerning threading the barrel of my scorpion. First of all we couldn't remove the old barrel without potentially damaging the upper rec. He manufactured a sleeve that fits like a glove over the existing barrel and threaded it for 1/2x28. He duracoated it and installed two setting screws and loctite to hold in place. Looks better than factory barrel, and folding stock fits over it too. I have pics if anyone is interested. Included a thread protector... all for $250.