Barrels: Cut Rifling vs. Button Rifling
Our barrels come in two forms: cut rifled and button rifled. The price difference is simply the cost difference paid to our primary barrel supplier, Rock Creek. We pay $125 more for a cut rifled blank so we charge $125 more for it. They charge more for it because it takes substantially longer to produce due to the way the rifling is imparted to the barrel’s bore. At PVA that is the end of the differences. The CReS material used is identical, the material is drilled and lapped with the same equipment, normalized the same, then lapped and normalized again… the same.
The discussion of “cut rifled vs. button rifled” barrels dates back quite a way in the world of precision rifles. The vast majority of barrels in the world are button rifled for the simple fact that they’re much less time consuming to produce. That doesn’t mean that they’re any less accurate than a cut rifled barrel. In fact, there are some conditions that cut rifled barrels are actually LESS consistent barrel to barrel than a button rifled blank.
The button rifled approach swages the steel of the barrel into the form of the rifling. Most lower cost barrels formed this way have a critical step not included after the rifling is formed; stress relief. Stress relief is also known as “normalizing”. We normalize the material before drilling and reaming, then we normalize again after buttoning and before finish lapping to get the most consistent finish inside and the most consistent results downrange.
Some concerns are brought up continually from customers looking to understand what the difference in process means to them. Some of the most common concerns or discussion points are listed below.
- Longevity (barrel life)
- Accuracy (most correctly termed ‘repeatability’)
Across the industry this is not the case to have otherwise identical processes for 2 product lines. Typically, the largest commodity barrel makers out there are using much softer material for their button rifled blanks. It is easier on the buttons, easier on normalizing (if they even normalize after buttoning) and more reliable in bulk process not to break buttons off in the blanks. The hardness of the barrels is critical in only 1 metric and that is longevity.
Softer material breaks down in the bore faster and the life of the barrel is diminished due to it. We have seen several competitor barrels in 6.5mm Creedmoor that only lasted 1800-2000rd before they were unable to hold 1moa at 100yd. Upon dissection the material hardness was measured and shown to be 5-6 points lower on the Rockwell C scale. That is the difference between a 6.5 Creedmoor that lasts 3500rd and one that goes only half the distance.
This is a valid argument by the proponents of cut rifled barrels lasting longer when comparing the bulk commodity button barrel to a flagship cut rifled product. Therefore we spend more money on the raw material to get a better starting point for our barrels. We aren’t out to just cut the cost, we needed a product that was just as good through the use of actual engineering and process control. So a word of caution when it comes to comparing barrels with ours: the barrel may shoot very well (a nod to the gunsmith’s skill) but the softer barrels don’t shoot as well for anywhere near as long as a harder barrel.
As far as how the two shoot on paper is indistinguishable in our testing. If there is an advantage to the cut rifled barrels in performance or longevity the advantage has yet to be realized with the standard that PVA holds its barrel blanks at. This is true of the cleaning and break-in as well. Since the barrels are double lapped the break-in for either prospect is the same (see our Break-In article) and cleaning regimen is the same.