. Although our machines are state-of-the-art, the process itself is the oldest and slowest method of rifling a barrel. What im saying is from what Ive seen from two different barrels with diferent styles of rifling. Conventional rifling has lands and grooves. Conventional rifling uses a tool to remove material from inside the barrel. A rifled barrel is slightly undersized so that the rifling will cut into the projectile. Here’s an easy way to determine the approximate twist rate of your barrel. Dave, if you are going to be pulling your cutter by hand, I would stick with a high speed or cobalt tool, rather than carbide. Button rifling doesn't cut. There are four ways to produce the grooves: Cut rifling. As you draw the rod back, the patch should fall off. Cut Rifling Machines. Inside of the rifled barrel of a French 75 mm gun of WWI. Shows in detail how to build and operate both the scrape cutter and the hook cutter. Then, grooves are cut, leaving the original hole's surface as. The broach is a piece of steel alloy that provides strength. The bullet you want to shoot will determine your required barrel twist rate. All barrels are prelapped/honed before rifling and finish lapped after rifling. this single point cut rifling process requires a single cutter to make 120 individual cuts to accurately rifle each bore. Cut rifling is a single point rifling system in which the cutter is pulled through the barrel and rotated at. 4 According to the American Precision Museum, who currently displays the Robbins & Lawrence. Contact us to discuss your large-scale defense projects. 45 to . Mar 6, 2006 2,869 2,608 CENLA. Add to Wishlist. Button rifling. They are owned and operated by shooters who have been involved in barrel making for many years. The discs are produced by milling away parts of a larger diameter stock piece, leaving the discs standing upright on the support rod. Rifling twist is consistent from one end to the other. Reactions: stefan73. 0001 inch, or 1 ten-thousandth of an inch, at each pass, thus taking several hundred passes to rifle a barrel. The discs are produced by milling away parts of a larger diameter stock piece, leaving the discs standing upright on the support rod. is in the process of starting a cut-rifling business - the last time I talked to him, he was about to head over to Boots' shop for a couple of weeks to try to learn some of the finer points of the cut-rifling process. This greatly improves the accuracy of the bullet over longer distances. We thought of something like John Browning’s hardwood rifling machine, updated, but it seems wiser to first undertake a survey of available and historic technologies. Verified answer. The work hardening of the barrel steel caused by the button results in a bore surface that is denser than a cut surface. The broaching tool is. . LBC uses precision cut rifling when making their barrels and the barrels on these match rifles have a 1:10″ twist with five lands and grooves. This required multiple iterative passes of a cutting head for each groove (at first this was done with a "scrape cutter", and later a "hook cutter"). The sides of the grooves are parallel, but the sides of the lands are not and the 5R carries this to an extreme. Kolbe (past owner of Border Barrels) covers all the important processes: steel selection, hole drilling, hole reaming, and rifling (by various means). [1] It causes the bullet or projectile to spin as it flies through the air. The cut rifling machine is old but functions flawlessly. Kr. The button forces the steel. 308-inch bullets instead of . The Broughton 5c rifling looks alot like the rifling in a glock no sharp edges. The quality of the barrels turned out by this method was very good, but it is a time-consuming process that slowed down production (the scrape cutter rifling process took about an hour to. Cut Rifling – This is an older, more traditional method that isn’t commonly used today. Button rifling is simpler and faster than cut rifling and usually less expensive. Button rifling had been around for a. In order to produce rifling similar. However, the latter IMO, would be pointless as it leaves stresses in the barrel. In addition, the article describes a new (and somewhat radical) method, Cation Rifling, which employs acid to etch. Conventional rifling has sharp 90-degree corners from the top of the land to the bottom of the groove. AC KRO GRUV is Mossberg version of marlins Microgroove ~~ MicroGroove Rifling [edit] Micro-Groove rifling. A solid sphere, of diameter 18 cm, floats in 20°C water with 1527 cubic centimeters exposed above the surface. This process takes significantly longer than. The effect is that the cutter digs in on the sides next to the lands before it hits in the middle. « Reply #1 on: June 14, 2008, 03:21:54 AM ». 224. You wee left with a long spru that has to be manually cut off. Rifling in a . It produces moderate amounts of stress in the steel, which can be stress-relieved and straightened. The big bore . May require live pilot with appropriate sized. 5R is an improvement over conventional rifling by changing the shape and configuration of the lands and grooves. Rifling is too often taken for granted, but its effect on accuracy. Button Rifling – This fairly common type of rifling is completed by using a tool called a button. This was done either with a rod with a hard piece of steel. Rifling cutter US2757580A (en) 1952-11-07: 1956-08-07. This makes it expensive. The cut-rifling method removes metal from the surface of the bore to create the grooves using a single-bladed, hook-type cutter of groove width that is pulled through the cold barrel. JES Reboring converted a Remington 760 slide action from -30-06 Whelen to 35 Whelen Whelen. 4 groove barrel rifleing Do a search on the hide about cleaning 5R rifling etc. Single-point cut rifling process is the most straightforward way to rifle a barrel, but it is also the most time-consuming and doesn’t offer much advantage over the other methods beyond being the most approachable. Bartlein Barrels is a manufacturer of precision cut-rifled barrels used for hunting, precision tactical shooting, and benchrest competition. #3. Hammer-forged rifling is formed by. Cut rifling inflicts virtually no stress in a match barrel shop as the rifling machine only takes a tiny cut from a groove at one time. The broaching system used by some European manufacturers utilizes a series of cutters that cut all the grooves at. This video shows the process of cut-rifled barrel-making by one of the world's best barrel manufacturers. The four basic methods of making rifling in a barrel are single-point, broach, button, and hammer-forged. Drilling small, deep, straight holes is time consuming and expensive. Cylindrical propellants - See Powder, tubular; D Top• Rifling produced by hook cutting, scrape cutting, and broaching is often referred to as cut rifling • Cut rifling tends to leave more forensically useful marking inside the rifled barrel than do the other rifling. Machine marks are caused by poor tooling or cutting speed causing the cutter to chatter leaving these marks. Cut and button rifled processes can be altered to accommodate varied twist rates, other than in extremes, whereas cold-hammer forging needs the mandrel within to be the exact shape of the bore, including the twist rate. This method is used on most high-precision target barrels. Cut rifling is more precise and makes a difference for those. What is Button Rifling? In button rifling, the “button” is actually a tool made of tungsten carbide. This comment assumes this rig is a cut rifling machine. There. Minuteman. Definitions. This rifling-machine post will still be here when you come back). This widly held belief was one of thep principal reasons Marlin switched to the Ballard style. The actual hammer-forging is illustrated starting at 1:15 in this video. 308") so it would seem that it wouldn't take too much to make rifling but it is kinda important that it is twisted just right, that is the difficult part. 1. It is best for barrels that do not require deep rifling grooves. . Even if scrape cutter rifling requires less time to produce grooves, both processes are time-consuming and incompatible with large-scale manufacture since the cutter may require several sharpening or even replacement (Biasotti, 1981; Bonfanti, 1997). The carbide button tool is attached to a rod of high tensile steel, and the other end of the long rod is attached to a. The results of rifling gives a barrel its _____ Class characteristics . Lands and grooves having a rounded profile. The only cut rifled 1911 barrels I am aware of are Lissners. The article explains four common methods of rifling the interior of barrels: Cut Rifling, Broach Rifling, Button Rifling, and Hammer Forging. Traditional (Lands-and-Grooves) Rifling Standard rifling in pistols, which seems like an after-thought to most people, is called Lands-and-Grooves rifling. To button rifle a barrel a carbide plug, or button, with a reverse image of the grooves and raised lands of the rifling, is pulled down the bore. Fairly sharp , (but not too sharp as to cut the patches) lands grip the best. Rifling Photograph of Rifling --- spiral grooves cut in or forged into the bore of the barrel that impart a rapid spin to the single projectile, gyroscopically stabilizing it in flight for greatly improved accuracy over that of a smoothbore gun. The hook cutter is pulled through. groove deeper on one side than the other, thus giving the illusion of "ratchet" rifling. Here are some generalizations. ) Or, hammer forging can be used to form rifling. The rifling process is a key part of barrel manufacturing, resulting in lands (bore) and grooves that create a spiral down the length of the barrel. Not sure about the cut or button detail. 012 deep. My dad made both button and scrape cutter rifling machines to rifle his ML barrels up to 60 cal and 2in dia. The simplest types of rifling buttons merely cut the grooves into the barrel. How does button rifling compare to cut rifling? Button rifling is generally considered more cost-effective than cut rifling as it requires less time and labor. The cutter removes approximately . To make a rifled barrel, normally a hole is deep-drilled in a steel bar. then a set of gripper fingers engage the adjuster and raises the cutter head for. Williams Scrap Iron & Metals Inc - Recycling Center in Victoria, 2690 MUNNS RD, Victoria, British Columbia, Canada. We proudly create rifle barrels for F-Class. That young man "converted" one side of the rifling machine to turn out a . The ogives jammed into the leade. Bartlein Barrels only uses single point cut style rifling, no buttong rifling and no broach cutting. Forged rifling. The cutter is shaped like a wide and squat "t" to fit into the slot with the center vertical of the "t" passing through the hole. Scrape cutter rifling is very similar to hook cutter except that as a different scraper is used for each groove, there will be no underlying similarity between the grooves. . The quality of the barrels turned out by this method was very good, but it is a time-consuming process that slowed down production (the scrape cutter rifling process took about an hour to. I had him make my . Scrape Cutter. Re: 6 groove vs. 60. I am looking to build up a lever . DeHoff gun barrel machines are used by over 50 firearms companies all over the world. In addition, the article describes a new (and somewhat radical) method, Cation Rifling, which employs acid to. Krieger Barrels offers a wide variety of twist rates that are appropriate for popular bullet weights in any given caliber but it is also possible to specify your own custom twist rate. Cut Rifling Cut rifling is the oldest method of rifling a gun barrel. Historically, material removal processes were used to define the grooves by cutting or scraping the inner surface of the drilled barrel blank (Bolton-King, Bencsik, et al. The. This method uses a carbide “hook” to cut a single groove over many passes. Krieger Barrels has been making premium rifle barrels for over 30 years. When adjusting the cutter, the screws need to be loosened first, then turn the. 555-557): "Until WW II, the bore and rifling of the '03 barrel was finished by the above described hook cutter rifling method. 300 Blackout Barrels for 2022 Faxon Firearms . The first barrel was converted to a 35 caliber barrel, and then a variety of other calibers were. the grooves to be cut are carved in relief on the button surface. The six groove deep rifling was designed to spin the soft lead shells that were generally being shot at the time. In addition, the article describes a new (and somewhat radical) method, Cation Rifling, which employs acid to etch rifling. "The most important part of such a gun - the rifling in the barrel - is in the Ballard the best yet produced. All the new barrels are 1in 18", some say a fast twist for this rifle. Courtesy of FirearmsID. See the figure below. Cut-Rifling - All the Difference in Custom Rifle Barrel Fabrication. Polygonal rifling . Here's a breakdown of the 3 main types of rifling, Cut rifling, button rifling, and cold hammer forged, and what we believe are the benefits. Rifling refers to the spiral grooves that are cut into the internal surface, known as the bore, of a gun barrel. The button is pushed or pulled through the barrel to press. Rifling twist rate can be changed. The broach is fed down the barrel with a rotation that matches the twisting ground in the tool, with each progressive tooth increasing the depth of the cut. These methods are the „ scrape cutter " method and the „ hook cutter " method. Each disc on the broach is a mirror image of the. Grooves: Round bottom CUT rifling . Please allow 3-5 business days from order placement to shipment to allow us time to contour. The price difference is simply the cost difference paid to our primary barrel supplier, Rock Creek. A good cut-rifled barrel will retail for $400 and up, while quality button-rifled barrels may start at $150. Which is why we’ve made it our mission to provide a hassle-free foam recycling service for our. (a) What are the weight and specific gravity of this sphere? (b) Will it float in 20°C gasoline? If so, how many cubic centimeters will be exposed? Verified answer. Place the rifling cutter into the barrel of the gun and begin to make the cuts. The work hardening of the barrel steel caused by the button results in a bore surface that is denser than a cut surface. . "The most important part of such a gun - the rifling in the barrel - is in the Ballard the best yet produced. It takes a LOT of effort to pull a . This is on a CBA Heavy category rifle and using cast bullets of course. Marlin likes to call this process "Ballard rifling" because this was how theRe: Rifling cutter shape. Then button rifled without and honing or lapping before or after drilling. The part that grips the patch is the edge of the rifling. The cut-rifling method removes metal from the surface of the bore to create the grooves using a single-bladed, hook-type cutter of groove width that is pulled through the cold barrel. It is best for barrels that do not require deep rifling grooves. Hold the equipment square, parallel, and concentric everywhere, because precision is the byword in barrel making work. Then get a large enough milling machine to go with your lathe and build the tools and equipment up. Occasionally during this process something goes wrong. The . We do single point cut rifling. A machine pulls a sharp cutter down the bore, removing a thin layer of steel in a spiral. A spinning bullet is found to be more stable in its trajectory, and is therefore more accurate than a bullet that doesn’t spin. Ballard rifling came about during the years Marlin made Ballard rifles. Are you meaning to say that they use a button to form their rifling? Because a button doesnt cut and your claim they they use a button to cut is objectively incorrect. The first cut was shallow. The most likely problem from button rifling is in skinny barrels which taper to a small. The seller says, "its an early 70s gun, with ballard type rifling" Well, I for sure knew better, and should have not done it, but took his word and then looked at the actual rifling later. Conventional lands and grooves are replaced by “hills and valleys”. This has been the old standby in terms of rifling because it nearly never. A broach has mulitple cutters on it. Do this preferably from the breech end to avoid damaging the barrel’s crown. 58 and . The pressure exerted by a burning charge of powder in the chamber of a gun. Invented in Nuremberg around 1520, the cut-rifling technique creates spiral grooves in the barrel by removing steel using some form of cutter. For a pistol, broach or button does an equally fine job. Building on a savage action, have an additional post in competition forum but figured I'd ask the barrel question here Guess wondering the accuracy difference one could expect out. 30-cal. The carbide button tool is attached to a rod of high tensile steel, and the other end of the long rod is attached to a. The cutter removes approximately . Accepts and recycle scrap materialsWhile the method whereby the grooves were first produced seems not to be definitely known, it can be said that until fairly recently there have been two methods in. rifling - the cutting of spiral grooves on the inside of the barrel of a firearm. Barrels are rifled using a left or right twist. Button rifling introduces stress because it doesn't cut, it just literally pushes all the metal it doesn't. Conventional rifling, while effective, can be improved upon in two ways. The button was also turned by a spiral guide,and was pushed and. Many of the largest and most respected names in the firearms industry rely on us for our outstanding commitment to quality and on-time delivery for their firearm related tooling. . Fig. Rifling tool having one or two raised cutting edges that cut the grooves of rifling. Single-Point Cut-Rifling. Twist. 30 cal, say 1 in 10, 11 or 12" (if you offer one of each), you’ll need a mandrel appropriate to each. Gun barrels are the most critical part of a quality firearm, and our products are hand-made by craftsmen experienced in both machine tooling and competitive shooting. This is because the cutter is not supported on both sides of the cutter box. Rifling can be cut into the inner surface of a barrel using a broach, the rifling can be formed using a hardened steel button, or the rifling will be formed through a process called hammer forging. Just making the buttons took a fancy cutter grinder and diamond wheels as well as a premium grade of carbide. This method produces almost perfect concentricity between bore and. A long rod pulls a small hook in a hard-steel, bore-diameter cylinder, removing about 0. 5355 posts · Joined 2019. Check out the GROOVES above. Cut Rifling: The oldest method of rifling a barrel, the process removes metal from the bore using a single-blade, hook-type cutter. 4' stick of 4" SCH-40 PVC with a strip of something wrapped around it like a barber pole. The only exception to this rule is Forsyth style rifling with wide grooves, and narrow lands. This type of rifling is produced with Hammer Forging . After reaming and straightening,a solid lube was applied to the bore and the barrel was put into an oven at 400deg to set the lube which was a low temp glass. For large caliber solutions we use UNISIG B-Series deep hole drilling machines for drilling and bore finishing and a R100 or R200 CNC rifling machine. Normally expressed as the peak pressure in pounds per square inchWe rifle by the single-point cut-rifling process. None of which can be done on a standard lathe. This is the rifling bench from Dixon's 2008. To make a cut-rifled barrel, a hook is pulled through a rotating barrel blank that cuts away material to create the rifling in a specific twist rate. If the barrel chamber finish reamed to the desired headspace still causes the issue, then a leade reamer is needed. "Button rifling is an efficient and easier process than cut rifling to get a quality barrel," he said. The twist is exact, where as other forms of rifling can have variances due to the process they use. The 80DL was made from 1941-1964 and the 80C was made from 1941-1971. We build 90% of our rifles with Bartlein 5R tubes. methods - The size of a firearm barrel may be designated in different ways • The most common is to specify its caliber which. Whether it’s button rifling (100-400 Series), broach rifling, cold hammer forging, or single-point cut rifling (500 Series), there are plenty of valid options to choose from. A metal scraper of the same shape attached to the ramrod was used to sweep away the fouling. As the hammers compress the outer surface, the blank is reduced in diameter and lengthened, simultaneously creating the bore and rifling. This carbide Multi-flute Reamer of usually 4 or 6 Flutes is pulled or pushed through a gun drilled barrel to accurately control the surface finish and size of the ID of the barrel prior to rifling. As previously stated it is hard to get extra deep rifling to seal, and not burn up the patch. e. In a cut barrel the twist rate is conrolled by turning the cutter as it passes down the barrel. We start with 4150 chrome-moly or 416R stainless steel double stress relieved bar stock, bore with the renowned Barnes gun drill, ream with an industry-standard Pratt & Whitney reamer, and then hand lap each barrel to our high-precision standards. 0001 inch on each pass, thus taking several hundred passes to rifle a barrel. Most of the weapons the firearms examiner will encounter have been rifled by one of these two methods, and mostly by the second. How many grooves does a hook cutter make with one swipe? 1. 218/. I don’t have a more accurate date for Kollner. A sine-bar scrape- or hook-rifling setup is far more suited to one-offs. The cutter is adjusted to cut one- to two-thousandths of an inch of metal on each pass. This type of rifling is produced with hammer forging; rifling with rounded profile. A rifling broach is a long rod with a series of cutter discs perpendicular to the axis of the rod. Bartlein Barrels. Button-swaged rifling. IMHO the real difficult part would be mastering how to. 400″ in diameter; the “datum” or “basic” line. With cut rifling, grooves are carved into the barrel using a cutting tool, whereas with button rifling, grooves are pressed into the metal using a hardened steel button. The rifling process is a key part of barrel manufacturing, as rifle and pistol barrels require rifling to shoot accurately. Our barrels are gundrilled with counter rotating gundrilling system. Which rifling technique involves the use of cold-working to harden the interior of the barrel and permits the use of. That gas seal gives polygonal guns an. Gun barrel markings. 5R is a 5-groove rifling pattern with sloped or angled sides to the lands. 0001 inch, or 1 ten-thousandth of an inch, at each pass, thus taking several hundred passes. Randy Gregory of Medford, Wi. This cutter body includes a single carbide cutter. 22 caliber barrels or pellet guns. due to the superior throughput of hammer forging and button rifling. Rifling Cutter Body & Carbide Cutter. We use a HAAS T-L 2 Lathe for the ent. 22 to 50 BMG. The result is a clean, 3-degree pocket hole with minimal tear-out, around either the pocket or the pilot hole. Broaching uses multiple cutting surfaces (cutters) mounted on the same axis to progressively remove metal. The same practice applies to rifling, buttoned or cut. With deeper and narrower grooves being more efficient at giving the bullet spin, the form and number of grooves can vary depending on the firearm and ammunition being. It is mostly all automatic with a long shaft with a ground cutter made from TanTung or Cobalt. Broached rifling. Button barrels the twist is mostly controlled by the shape of the button and the twist rate can vary depending on many variables. Longer life. Only way I could get "blue" on the patch,. Single-point rifling. The path of the projectile in flight. There are 5 different rifling methods, cut, button, broach, cold hammer forged and ECM. The hammer forged barrel cost a lot more for up front investment in machinery to do the process. if you're talking about seating conicals, you need to be using shallow groove rifling. The TAC 501 rifle system is a heavy 416 SS barrel with cut rifling, manually operated, detachable box magazine with five +1 shot capacity. to the ratchet rifling shown above, you would have to "re-cut" the tops of the lands, I don't know of any barrel maker. They also have a great rifling machine and have developed a great scrape cutter to use with it. The first muskets to use this technology were called rifles. 22 to 50 BMG. 012 deep. The six groove deep rifling was designed to spin the soft lead shells that were generally being shot at the time. Many ways have been developed for making a bullet rotate through a. In order to produce rifling similar. It happens when the top of the rifling cutter is ground on an angle and it will cut the. 5. Cut rifling is the first rifling method to date which was invented in Germany around 500 years ago. Cut rifling creates spiral grooves in the barrel by removing steel using some form of cutter. This required multiple iterative passes of a cutting head for each groove (at first this was done with a "scrape cutter", and later a "hook cutter"). Unlike the above-mentioned barrel makers who usually specialize in one rifling method (either button or single cut rifling), Rock Creek offers either rifling solution. com. Polygonal rifling. [2] The first muskets to use this technology were called. READ Full Article. You can see this in the image above . 150-gr. The broach is fed down the barrel with a rotation that matches the twisting ground in the tool, with each progressive tooth increasing the depth of the cut. Also when a rifling head is used in scrape or hooked rifling the groove depth will be shallow when the head is introduced into the bore and again when it is removed at the muzzle end. Scrape cutter. pulled button also continues. In its traditional form, cut rifling may be described as a single-point cutting system using a “hook. The ideal is to have the correct groove diameter, . 6. The discs are. Gun-maker Bear Creek Arsenal has a good article on its website about rifling barrels. 0001 (not . Starting with a pilot section, a rifling broach has multiple rings of cutters whose axial cross-sections match the rifling layout. Take your rotary cutter apart. In this video, Jim goes behind the scenes and shows the process he developed for rifling our 44" muzzleloader barrels. Yes cast bullets are fine through the polygon barrels. While the number of companies offering reboring has decreased considerably in the past few decades, the few remaining in the U. Slightly, custom barrel makers change tooling more often producing better barrels @ a greater cost. Polygonal rifling is common in pistol barrels, and is used by Glock (Gen 1-4), Walther, Heckler & Koch, and several other companies. This process is no longer common. Button rifled barrels are usually softer hardness wise to push / pull the button thru the bore. See the figure below. Button rifling which is much faster is the result of pulling or pushing a button with projections on. What is broach cut rifling? Broach rifling is a metal cutting procedure that works to take out material from each groove. if you're talking about seating conicals, you need to be using shallow groove rifling. Whereas it had taken an hour to cut the old Ballard-style rifling with the scrape-cutter method, a barrel could be button-rifled in less than five seconds. 5R rifling tends to erode faster than cut rifling with wider lands and narrow grooves. #2. The process is usually very consistant, with a very fine bore finish, and produces a better than average accuracy, with less cost than cut rifling. 0001” of material at each pass, thus requiring. Drill and reamer marks are not removed by button rifling as they are with cut. Done well, button rifling probably makes the next smoothest barrels. Rifles and handguns have rifled barrels, that is, spiral grooves have been cut the length of the interior or bore of the barrel (Figure 2. Conventional rifling has lands and grooves. The broach is a piece of steel alloy that provides strength. 40 – 1/48. Each groove is cut individually and with multiple passes, making it time-consuming and expensive. Minimal induced stress. Unless I build a sine type machine and cut the rifling. The broach is a piece of steel alloy that provides strength. A rifling button is kinda like a tailpipe expander. Generally, blades that cost $50 or more are worth sharpening while it is better to replace cheaper,. The result was a bore that looked like the patched ball was sliding on thin rails. In its traditional form, cut rifling may be described as a single point broaching system using a "hook" cutter. rifling occurs when the groves and lands are put into the barrel - this allows for the bullet to have a spin on it so it flies better 1 manufacturer chooses a rifling process, the class characteristics of the weapon’s barrel will remain consistent, each will have the same # of lands and grooves, w/ the same approximate width and direction of. formation, shaping - the act of fabricating something in a particular shape. The spiral tracks of the hammers can often be seen on the outer surface of hammer-forged barrels. Lawton did cut rifling, and also produced the worst barrel regardless of rifling method my gunsmith ever had in his shop with 33 years gunsmithing experience. Images of Cut-Rifling process courtesy Accurate Shooter Rifling is usually expressed as a twist rate; that is the length required to complete a full revolution along the horizontal access. All of our barrels are manufactured using single-point cut-rifling and each and every barrel we make is thoroughly inspected and held to the same premium match grade standards, whether its an ammunition test barrel, a custom bolt action barrel or a ready-to-install finish chambered AR15. 35s, to ensure stabilization of even the longest bullets. Equipping the barrel with the spiral grooves that spin-stabilize a bullet is the essential operation that defines an entire category of firearms. I agree with you that "Pac-Nor does in fact use a button" but they are not cut (I just called and asked this specifically). The quality of the barrels turned out by this method was very good, but it is a time-consuming process that slowed down production (the scrape cutter rifling process took about an hour to complete. A button puller is another 1 axis machine with highly custom tooling. 016 deep. It is also the term (as a verb) for.