Reamers are precision ground chamber cutters perfectly sized and contoured for a firearm’s cartridge. Reamers are critical to cutting the barrel for accuracy and function. Pistol barrels are primarily straight-walled, making cutting chambers either by hand or machine somewhat easy. Pistol reamers are important for accuracy and function. Too short a chamber and the pistol or revolver might not cycle. Too long and you can get excessive leading and accuracy loss.

I buy my barrels with short “gunsmith” chambers, allowing for finish reaming after the barrel has been installed. In most cases a “chamber reamer” can be used to cleanly cut the remaining five to 10 thousandths for proper headspace. But the chamber reamer doesn’t always cut the “throat” which is the transition area from smooth chamber wall to the barrel rifling (lands and grooves). A barrel throat should be angled at about two degrees, and, by using two reamers, the chamber or roughing reamer, and the throat or finish reamer, you will save tool life and get better cuts. If you’re using a semi-fit barrel, the finish reamer can do all the work for the occasional barrel fit.