Hi, while I'm mostly happy with the Howell conversion cylinders, there is one aspect of the Howell (and Taylor) that I dislike. The cylinder bolt slot is always cut much wider than necessary. This was first noticed with the 1858 conversions, and continues in the Colts. The cylinder bolt slot is cut ~0.010" wider than the bolt. That means that there is cylinder wobble ~0.005" either side of the bore axis. The forcing cone of course will handle that misalignment, but a wide slot doesn't contribute to good accuracy. Good accuracy shouldn't be secondary to Howell not having any returns or complaints.
The wide slot is a purposeful design, it fits in all guns irrespective of bolt width variance. Frankly, it sucks! I would much prefer a tight cylinder bolt slot, even if a adjustment of the bolt is required to fit the cylinder.