Our shop is the manufacturer of these cans. CNC machined aluminum construction. We normally thread them in 1/2x28 (standard threading), but can custom build to fit your specific need. These are marked as .22cal but can equally operate on .22mag and .17 caliber pistols and rifles. These are not centerfire or full auto rated. All NFA rules apply. If you are a Missouri resident, we can help with the application if you come to the shop in person. All other transfers will be Form 3 to your NFA dealer, and they will collect your tax stamp money and handle transfer to you. Out of state Dealers call for pricing avail for multiple can purchase.