This may be a great product for cartridge guns but my impression is it is a total no go for current made cap and ball revolvers. The smallest pilot does not even begin to enter the chambers of current made Pietta cylinders. The selection of pilots and a single reamer size (.4525) is a joke when it comes to cap and ball revolvers (I find it just plain limiting either way) which can have groove to groove diameters of .454 (an older standard) or more also even less than .4525. Chambers that are smaller than groove to groove diameter of bore still seems to be a problem with both Pietta and Uberti although I have read some models or special higher end production lines may have properly matching chambers to bore. Despite all the advice read and knowing better than to even dream of trying, an attempt at reaming without a pilot yielded exactly what was warned. This was a off center crappy ream despite all attempts at finesse. To top it off an attempt was made to hammer the smallest .448 pilot all way down into the cylinder in hopes of using it to guide the reamer the rest of the way down hopefully correcting most of the mess made by the attempt to ream without a pilot. That successfully wedged the pilot partially down the cylinder locking it there for good. All attempts to hammer it out from behind through the nipple hole failed.. Two hours of hammering and not a budge. Thankfully spare cylinders are a perfect drop in these days. Shopping at the site that sells these Brownells and Manson is a total nightmare. Their websites are lousy and searching for a product is like solving a riddle with no straight clues or answers. A more complete set of pilots and a wider selection of .45 caliber reamers (453 and .454 seems to solve a wide range of bore sizes) would have saved lots of frustration. The futile attempts in using these tools the wrong way is not their fault but lack of motivation to openly offer tools that allow more flexibility in work rather than tying the customers hands is. Do not get this kit (.45 caliber) for current or any cap and ball revolvers unless you are sure they are the correct size. It's on you to figure it out and my impression is these kits are not good for current production Pietta and Urberti cap and ball revolvers. The .38 cal kit is a cartridge gun only kit and looking at the reamer specs (0.358) will reveal that immediately. You would think that insiders in the firearms industry would want to help the buyer make an educated purchase if their products have a narrow amount of use.