As the self-contained metallic cartridge because popular, a niche industry developed in converting percussion revolvers to use the new cartridges. One of the first of these conversions was designed by F. Alexander Thuer and marketed by the Colt company itself. Thuer's conversion was put into production while the Rollin White patent was still in force, and so it was prevented from using a bored-through cylinder. The get around this, Thuer developed his own proprietary centerfire cartridge with no rim and a very slight taper. These cartridges were loaded from the front of the cylinder and press-fit into place. While this made the conversion legal to sell commercially, it had a number of problems (in addition the use of proprietary ammunition) which led to it quickly losing favor as soon as White's patent expired.