OBERMEYER RIFLED BARRELS Quality Rifle Barrels Since 1962
23122 - 60th Street Bristol, Wisconsin 53104
A Note on Steel
During the manufacturing process, barrel-quality steel is carefully controlled and inspected to ensure the material structure is correct for rifle barrel use. There are two basic steel options available: stainless steel and chromium-molybdenum alloy steel. Stainless steels are special, gun-barrel quality grades of Carpenter or Crucible 416. Our suppliers of chrome-moly steels have changed as the American steel industry continues to suffer bankruptcies and closures due to competition from cheap, imported steels. (For more information regarding the impact of the steel industry crisis on American manufacturing and national security, see "Blood and Iron Pyrite" by Eric J. Obermeyer in Chronicles: A Magazine of American Culture, Vol. 28, No. 4, April 2004, pages 51-53.) This has resulted in a situation where high-quality specialty grades of steel are becoming harder to obtain, steel prices are going up, and minimum order quantities are now about 10 times larger. This special quality steel is not imported, and two mills in Europe have turned me down because small quantities of steel are not worth their efforts. A number of custom barrel-makers are working together to pool resources in order to have the ability to place combined orders large enough to meet the quantity threshold. Standard raw chrome-moly blank diameters now will be 1-1/4" and 1-3/8", although this is subject to change with availability from steel suppliers. One of my former chrome-moly standards, 1-5/16" bar diameter, may be available in remnant quantities subject to stock on hand.
I am now using a new stainless steel from Western Branch Metals made by Outokumpu -- made in the USA. It is very good, and I'm told that it is made to be tougher. The people I buy this from are very interested in making it the best. The normal raw diameter for stainless steel blanks is 1-5/16".
Each basic type of barrel steel has its advantages, depending on the application. Chrome-moly barrels develop a fine-line erosion pattern in the throat, which I compare to fine gravel in a stream. With bare bullets, this can cause greater variations in velocity, due to drag exerted on the bullet in the throat region. This situation may result in an increase in the vertical dispersion of the shots, which is particularly noticeable at longer ranges. The testing I have performed in my target rifles leads me to believe that molybdenum disulfide coating on bullets, when properly applied, has a mitigating effect in this regard. (Each of the several chrome-moly match rifle barrels in .260 Remington that I have used in conjunction with moly-coated bullets has exceeded 6000 rounds of accurate life.) Also, chrome-moly -- having 40 to 50 points of carbon -- may harden in the throat area from use. This can cause damage to your chamber reamer if you try to set such a barrel back. On the other hand, chrome-moly takes more abuse from peening or abrasion, and this is a big advantage where field use is rough. It also tends to be stronger in cold-weather environments, such as might be encountered while hunting in Alaska, where the temperature is often below zero.
Barrel-quality stainless steel is usually identified as type 416R or 416RS, and it has approximately half the sulfur content of common, warehouse-grade 416. Stainless steel barrels will not harden in the throat area, which provides a big advantage for target shooters who plan to set their barrels back when the throats wear. The erosion pattern of stainless steel looks like a dried-up mud puddle, having large flats with fracture lines. This reduces the drag on the bullet, so there is less tendency for vertical stringing at long ranges. Sometimes, after a lot of use, a large piece may pop out from the throat of a stainless steel barrel, causing it to suddenly lose accuracy. Stainless steel will also scratch or peen easier than chrome-moly barrel steel of comparable hardness. In applications involving military weapons, this sort of material behavior would present a real problem, which is why chrome-moly is generally used. Stainless steel also has less ductility than chrome-moly, particularly when the ambient temperature approaches zero. Thus, a featherweight stainless steel barrel would not be the best choice for hunting in Alaska. Also, contrary to some people's notions, stainless steel is not hard to machine; it's actually easier than chrome-moly.
The type of steel used has a significant impact on the price of a barrel, since stainless steel costs approximately four times more than chrome-moly. In addition to the cost differential associated with the material in the barrel itself and with the material removed during the manufacturing process, there are additional costs due to drops resulting form having to purchase bars of certain lengths, which may not allow for full, end-to-end usage. Furthermore, the relatively high cost of stainless steel (and the tremendous difficulty of purchasing any barrel-quality steel in smaller quantities) forces the small manufacturer to tie up substantial amounts of money in inventory. Nevertheless, the greater cost of stainless steel does not automatically imply that it is a better material than chrome-moly for a given application.