Download & Print
 
As many shooters know, the throats in some single-action revolvers are quite a bit under proper spec. Some American-made and many foreign-made guns have cylinder throats much smaller than groove diameter. This condition raises pressure, is detrimental to accuracy and, in extreme cases, can prevent chambering a round.

Manson Cylinder Throating Reamers were designed to open the throats in these cylinders to proper diameters in each bore size. See below for cutting diameters of the various Throaters.

Reamers normally are designed to cut a minimum of .010” stock and generally don’t perform as well when removing less material. Because of this, a Cylinder Throating Reamer will give the best results if its pilot is a snug fit in the existing cylinder throats. To achieve the closest possible fit with different existing throat diameters, the reamer is made to accept removable pilot bushings. We stock pilot bushings in a wide range of sizes so you can choose one that fits your cylinder best. Don’t be surprised if your cylinder requires two or more bushings to fit all the throats tightly.

Accessory Tooling:

The following tools are suggested to make your job successful:

• T-Handle with ¼” hole for driving the reamer–this is a HAND OPERATION
• Good-quality cutting oil (Brownells Do-Drill)

Procedure:

Make sure the revolver is UNLOADED and remove the cylinder. Select a pilot bushing that fits the throat(s) as closely as possible, and fit it to the Reamer, securing it with a snap ring. Attach the reamer to the T-Handle and oil the cutting edges and pilot bushing. Insert the reamer into a chamber from the rear (as you’d load a cartridge) and slide the pilot into the throat until the cutting edge of the reamer stops against the lead angle into the throat wall. Begin turning the reamer in a clockwise direction while applying forward pressure, being careful to keep the reamer centered in the chamber. Since you’re not removing much metal, there shouldn’t be much resistance.

When through cutting, clean the Reamer of chips BEFORE WITHDRAWING from the chamber. Re-oil and repeat the process with the rest of the chamber throats. When satisfied with the job, clean the cylinder and re-fit to the gun.

These tools, like all others we make are warranted against defects in material and workmanship. If you have any QUESTIONS on their use, or suggestions as to how they might be improved, please contact us at the number above. REMEMBER it’s better to ask questions BEFORE you ruin your gun.

Cutting Diameters: 45 Colt—.4530”/.4525”; 44-Cal—.4315”/.4310”; 38-40—.4015”/.4010”; 38/357—.3585”/.3580”; 32-Cal—.3140”/.3135”