I wouldn't use them in my 11-87. There are two holes in the bottom of the barrel that allow gas to be bled off to operate the system. These holes lead into the forearm of the gun. If in using these shells some of the particals, perhaps very small ones, were to make it into the lower area of the gun some damage to the system may occur (pitting). May perhaps set the forearm on fire too!? Just get an old single shot and experiment away.