Various laws that may be restrictive apply in different locales in the USA, but Federal law does not ban shoulder-stocked pistols in the USA. It regulates them thru taxation. It is easy to obtain a Federal tax stamp for a "Short Barreled Rifle" in the USA, and requires only a completed application to BATFE/NFA Branch along with the paying of the special $200 tax. There are a few pistols that are exempted from this requirement. Some Lugers and M96 Mausers. NFA publishes a list. Check the list and law closely before stocking. I have heard {cannot confirm} that Federal charges can be filed for merely possessing a stock and a pistol that takes it unless said combination is registered.

Anyway, other pistols may be registered and then stocked.

Stocking a pistol may seem innocuous but in the USA it is a Federal crime of the first water. Don't do it unless the gun is registered and tax paid. I have myself registered a 1973 Browning High Power.

In putting together survival kit for my ski jaunts, some years ago I wanted to test a number of pistols off the shoulder but did not want to modify the pistols or pay the tax required by creating SBR's. I requested and was provided a legal review of a support of my own design that allows a handgun to be rested on the shoulder while firing {it is not attached to the pistol}. This legal review process is done thru BATFE/NFA Technical Branch. My design was stated in a letter from same that it did not create an SBR out of a handgun, and allowed me to fabricate the supports and test the pistols. Since I received differing opinions from several field offices of ATFE I wanted to know for sure and am glad I made the request. I have found BATFE/NFA Branch to be very helpful on many occaisions when I have called or written for clarification of some mysterious bit of "guncrankism".

As for the shooting of pistols off the shoulder, there isn't much to be gained by a good pistol shooter unless he is fatigued, under which circumstance the support does seem to help a bit. POI changes when most pistols are fired from the shoulder with a support.

I set up a support for Ruger MK1 and MK2 .22's, Browning 1910/1922 .32's, SIG P226's. I shot alot of ground squirrels with such supported pistols and found them to be an interesting diversion.