BENCHREST BARREL MAKING STEEL – WHAT IT IS AND WHY IT’S USED
Paul Tolvstad, KSS team member and benchrest shooter, is a seasoned competitive rifle shooter. He’s also a small-bore precision barrel maker.
Having worked with Broughton Barrels, Rock Creek Barrels, and Muller Works Paul knows a thing or two about the manufacturing process and materials used.
Here, Paul details the different types of steel used for making barrels for a variety of firearms and why.
416R is the most widely used stainless steel for barrel making and is what you’ll see on most benchrest rifles. It comes in all different sizes from 1” to 2” in diameter. There are several different companies around the world that make 416R stainless steel.
416R is a hardened stainless steel used in precision rifle barrels. This grade has good machinability; and, because of closely controlled manufacturing, it may be machined and lapped to a high finish.
These types of steel belong to the chrome-moly family. While these alloys do contain chromium, it is not as much as the chromium content found in stainless steel and therefore, they have less corrosion resistance compared to stainless steel.
4140 Chrome Moly is typically the most used barrel steel for all your rifles that use a blued barrel, such as most factory built rifles. The 40 in 4140 is specific to the amount of carbon in the alloy. Generally it is near .4%.
4150 or Chrome Moly Vanadium is the steel that is most typically used in the military style of weapons. It is considered machine gun grade steel. The 50 in 4150 is specific to the amount of carbon in the alloy, as again it is generally near .5%
These steels are used in the firearms industry mostly because of the ease of machining. Typically you will see the hardness somewhere between 20 to 32 Rockwell, “most” barrel makers prefer to be in that 24 to 28 Rockwell range.
When buttoning, different lubes may be used for doing Stainless or Chrome Moly barrels. When cut rifling, typically rake angles are adjusted to get the desired cut finish between the two different steels.