A newer method of rifling barrels, called Electrochemical Rifling, does not involve the normal machining processes of the other techniques. The idea of rifling a barrel to make it shoot truer and harder was not new, to be sure. 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. Pistols with polygonal rifling have smaller bore diameters than pistols with traditional rifling. The section on hammer forging is written by Ruger’s head of barrel making, Vern Briggs, and James Higley, Professor of Mechanical Engineering Technology at Purdue University Calumet in. It is best for barrels that do not require deep rifling grooves. Adding rifling to a bore that is sized for smoothbore use will likely impart little spin to the projectile and cause a lot of fouling from gas flowing between the projectile and the bore. Many ways have been developed for making a bullet rotate through a. 224. How many grooves does a hook cutter make with one swipe? 1. This is why I always go back to a cut barrel being better than a button barrel. 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. When running properly a carbide cutter is capable of rifling 10-20 barrels before resharpening. !f you look what is used. As previously stated it is hard to get extra deep rifling to seal, and not burn up the patch. You can harden the barrels before drilling, however. Why because they don’t understand the tooling for cut rifling is one. Rifling twist is consistent from one end to the other. This 3. LaBounty worked out a method for his rifling cutter to follow the old rifling, deepening it slightly. In traditional rifling, ‘tools’ such as buttons or broaching bits are used to either press or cut grooves in the bore giving the barrel a defined rate of twist. This video shows the process of cut-rifled barrel-making by Krieger Barrels, one of the world’s best barrel manufacturers. For a 1911, the firring, external barrel dimensions and the heat treat of the barrel are likely more important than the bore quality in the long run. A single cutter is passed through the barrel with cutting oil being injected from inside the cutter tube. The twist is exact, where as other forms of rifling can have variances due to the process they use. 0001" per pass. Starting with a pilot section, a rifling broach has multiple rings of cutters whose axial cross-sections match the rifling layout. PTG Replacement Carbide Tipped Rifling Cutter. Cut Rifling Cut rifling is the oldest method of rifling a gun barrel. RIFLING CUTTER (SCRAPE TYPE) TO DEEPEN EXISTING GROOVES IN BARREL USING EXISTING RIFLING IS GUIDE. at the center of the slot I drill through to the shoe recess, 0. The cutter is indexed around the. Button rifling causes the metal in the bore to displace around the die and is. 58. Much faster is the tungsten-carbide button. Choose Options. 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. It is best for barrels that do not require deep rifling grooves. It is threaded at the muzzle to 5/8 by 24 for the use of a muzzle brake or a suppressor but comes with a threaded cap. Cut rifling. Not many LR shooters use Kostysten and shilens for some reason but it is not due to lack of accuracy. Our barrels come in two forms: cut rifled and button rifled. The lathe pushes a single cutter, attached to a long rod, through the bore, carving each land and groove. Machine will cut up to a 26" by 1 1/16" barrel with a twist of as much 1 in 10". 012 deep. Turn the blade. Cut rifling is done by hand or with a tool that cuts one groove at a time through the barrel. Mine shot about 4" at 50 yards off the bench with dozens of load combinations tried. I was just pointing out that button rifling does induce more stress in a barrel than cut rifling, if that. The cutter rests in the cutter box, which is a hardened steel cylinder made so it will just fit the reamed barrel blank, and which also contains the cutter raising. Cut rifling creates spiral grooves in the barrel by removing steel using some form of cutter. The answer is yes, it is worth sharpening a circular saw blade. 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. The grooves were 3 or 4 times wider than the lands. A rifling broach is a long rod with a series of cutter discs perpendicular to the axis of the rod. 30-caliber cartridges are loaded with . A broach is merely a long tool with multiple cutting elements on it. . In the photo above, a hook cutter is depicted — This is used in a machine to remove material in a barrel as it creates spiral grooves. Cut rifling: A cutting tool is drawn through the bore, using either a spiral guide or a system of gears. The six groove deep rifling was designed to spin the soft lead shells that were generally being shot at the time. Back trench the cut along the inside of these lines. 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"). As I understand the Microgroove was cheaper and easier to manufacture, plus it made the rifles more accurate. Barrels: Cut Rifling vs. Screw the two parts together and start sharpening the cutter. S&W advertises that the smoother surface produced by EDM is an improvement over the broach cut rifling it replaced approxamently 1997 for most centerfire production revolvers. Showing 1 - 3 of 3 items. They use a wooden rifling bench,with about a 3" diameter maple cylinder with the rifling grooves cut into it with hand tools. The Foam Shop is committed to reducing the waste that ends up in our local landfills. 6. Yes cast bullets are fine through the polygon barrels. 254 posts · Joined 2023. Sounds like the barrel I threw away. These days, specialized equipment is used to insert a cutter in the drilled-and-reamed bore of the billet in order to cut and remove a small amount of steel with each pass of the cutter. 5R is an improvement over conventional rifling by changing the shape and configuration of the lands and grooves. Cutter is made to SAAMI specs. Removes metal from the surface of the bore using a single-bladed hook cutter. It is sometimes called "hook rifling" after the fishhook-shaped cutter used. (Here’s where cut barrels jumped a way up on my list from button sticks. Texas. Shape, number, and depth of grooves can be changed easily. Tooling – gundrills, reamers, rifle buttons. A rifling broach is a long rod with a series of cutter discs perpendicular to the axis of the rod. The article explains four common methods of rifling the interior of barrels: Cut Rifling, Broach Rifling, Button Rifling, and Hammer Forging. Polygonal rifling is common in pistol barrels, and is used by Glock (Gen 1-4), Walther, Heckler & Koch, and several other companies. Each cut, or groove, is separated by a ridge of metal called the land. Rifling refers to the spiral (helical) grooves that are cut or swagged on the internal surface (bore) of a gun barrel, which helps impart the spinning motion to a bullet when it’s fired. This article describes in detail how barrels are crafted, using both cut-rifling and button-rifling methods. 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. This is on a CBA Heavy category rifle and using cast bullets of course. Here are some generalizations. Button rifling can produce a very smooth interior finish, and the majority of winning 6PPC barrels are buttoned. The reason Ruger went with 18-3/4 inch twist on the Double-Action revolvers is because this is the pitch on the rifling broach cutters and there is only one company that makes them. Cut rifling carves the rifling into the barrel a very small amount at a time, just like turning on a lathe is cutting the metal itself generally by no more than 50-150 thousandths of an inch at a time (depends on the lathe and tooling). Kolbe (past owner of Border Barrels) covers all the important processes: steel selection, hole drilling, hole reaming, and rifling (by various means). fred January 2, 2015 at 22:01. So, cut rifling is still favored by many manufacturers. 22 caliber barrels or pellet guns. Lots of theories here. The cutter is a single tooth cutter that is adjusted for height by packing a thin piece of paper under the cutter,sandwiched between the cutting head and a half round slip of hard wood. The Broughton 5c rifling looks alot like the rifling in a glock no sharp edges. Fifty. Back in the day it was all about very deep cut rifling. A popular example of the latter is 5R rifling that originated during the 1980s by Boots Obermeyer, who continues to turn out match-grade, cut-rifled barrels in his Bristol, Wisconsin, shop. This process is repeated until the grooves reach the desired depth. This leaves sharp transition between raised lands and cut grooves. $691. Barrel Twist Rate – is the inches a bullet needs to travel in order to make a complete revolution. The Model 80 and 80E were made from 1935-1939 while the 80B and 80BE were made in 1940 only. Rifling. Oct 31, 2023 #23 ; Frank Green said:By: Glen E. The curved surface of the cutter holder opposite the working edge bears against the side of the barrel for support and alignment. 012 deep. Button rifling injects more as the 'button' pulled through the bore swaging the rilfing into a previously smooth surface. It performed as such in the field, changing POI 1 1/4 MOA vertical and 1/2 MOA vertical between cold and 4 shots warming, consistently moving the POI low and left over the 4 shots. Equipping the barrel with the spiral grooves that spin-stabilize a bullet is the essential operation that defines an entire category of firearms. 3. 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. This is the rifling bench from Dixon's 2008. The discs are. On the phone he said I had a good reputation locally for turning out nice machine work and asked me if I wanted to learn the art of drilling, reaming, cut-rifling, & lapping barrels. The Model 444 was introduced with a 12. 2. As I pull the rifling cutter through the barrel; I am able to index the cutter rod after each cut, by loosening the screw, and turning the cutter rod insert to the next hole. You impart a smooth surface finish, its cost effective, and the bad news of button rifling (setting up additional stresses in the barrel) is not. Cut Rifling. Don't know about Chanlyn's backlog. Next comes the big stuff — the massive rifling machines that single-point-cut the rifling in a precise, time-consuming process. 1 diameter. Regarding thoughts on 5r, an odd number of lands/grooves creates less stress on the bullet as it passes down the barrel and if memory serves correctly it also allows for better or more uniform gas seal with less stress on the bullet than even rifling count- add to that the. This type of rifling is produced with Hammer Forging . Cut rifling is the oldest method that is still being used. The broaching system used by some European manufacturers utilizes a series of cutters that cut all the grooves at. No additional stress on the barrel - no stress relief step is required. 13). Cut-rifling allows for a wide range of possibilities. 5R is an improvement over conventional rifling by changing the shape and configuration of the lands and grooves. 32 and . 280 posts · Joined 2017. The first muskets to use this technology were called rifles. 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. Also no barrel maker can measure for residual stress in the material. Cut rifling: A cutting tool is drawn through the bore, using either a spiral guide or a system of gears. Start by cleaning all of the parts of the rifling cutter, using a cloth and lubricant. The 80DL was made from 1941-1964 and the 80C was made from 1941-1971. In 1854, Henry D. One of our local CBA shooters uses a Broughton 5C barrel. 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. 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. 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 used. This lube was claimed to be the critical part of the process. While the number of companies offering reboring has decreased considerably in the past few decades, the few remaining in the U. It comes down to the people making them, the tooling, the process, the lot of steel, and the guy chambering it. The disadvantages are that he has to make his own tools, and that it is unsuited for series production. It's a production method for hundreds of barrels rather than being suited to a one-off. 40 – 1/48. These methods are the „scrape cutter" method and the „hook cutter" method. This is the technique that puts the minimum amount of stress into a rifle barrel. In a 50 caliber rifle, the cutter is ground to an exact radius to create a round shape that is a circle. We want a snu 2 fit. [1] It causes the bullet or projectile to spin as it flies through the air. What im saying is from what Ive seen from two different barrels with diferent styles of rifling. 58 caliber, 3 Land & Groove, 1 in 72" Twist barrels, and most importantly, just like the originals, the machine cut "Progressive Depth Rifling-just like that found in original Springfield rifle-musket barrels. The discs are produced by milling away parts of a larger diameter stock piece, leaving the discs standing upright on the support rod. Cut rifling and broach rifling both involve removing metal from the inside of the barrel, which produces “grooves” that lie in between uncut areas know as “lands. 6 x 0. Conventional rifling uses a tool to remove material from inside the barrel. 2. DeHoff gun barrel machines are used by over 50 firearms companies all over the world. Rifling in a . The cutter rests in the cutter box, a hardened steel cylinder made so it will just fit. The main focus of the article is on Cold Hammer Forging of. The elliptical gears were to speed up the return of the cutter [the rifling rod passed thru the barrel with a scrape cutter and a tapered "needle" to raise same]. It causes the bullet or projectile to spin as it flies through the air. The grooves are also cut with a ROUND or RADIUSED bottom. 4. What are six advantages of cut rifling? 1. May require live pilot with appropriate sized. 5. One purpose of Microgroove rifling was to increase the. It shows the way to build and use the slow-working scrape cutter. The purpose of rifling is to impart a rotational spin to the bullet along its longitudinal axis. When these marks are on the lands "only" it is from the drilling process before the final reaming to get the proper bore size. Drill and reamer marks are not removed by button rifling as they are with cut. Button rifling. Cut rifling is the oldest method of rifling a gun barrel. 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, and the hook cutter took about 15 minutes). if you're talking about seating conicals, you need to be using shallow groove rifling. com. Grab a cleaning rod, jag and patch. Push the the first patch all the way through the bore and out the muzzle. See Krieger Barrels being made, start to finish. 45 to . You will find button and cut rifling in those arena's. pulled button also continues. As the hammers compress the outer surface, the blank is reduced in diameter and lengthened, simultaneously creating the bore and rifling. 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. ”. During the search for rifling cutters I have found a lot information about rifling machines ( old and modern ). 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. Rifling Cutters at Pacific Tool and Gauge. Bullets fired down rifled bores must be slightly larger than bore diameter so they can be gripped or “engraved” by the rifling. Bartlein's state-of-the-art cut rifling machines can hold uniform twist rates to the 4th. The lap should now be pulled (and pushed) back and forth through the bore for about ten minutes, with. A broaching tool may be pulled or pushed along a workpiece. Cut Rifling: The oldest method of rifling a barrel, the process removes metal from the bore using a single-blade, hook-type cutter. Single-point rifling. The discs are produced by milling away parts of a larger diameter stock piece, leaving the discs standing upright on the support rod. 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. Cut rifled at this point in time is a rather expensive specialty product for high end precision barrels. It is available in three distinct finishes, including simple Black DLC, along with Titanium Nitride and Chameleon PVD as well. What is Button Rifling? In button rifling, the “button” is actually a tool made of tungsten carbide. A rifled barrel is slightly undersized so that the rifling will cut into the projectile. Each disc on the broach is a mirror. 5 cm barrel 24 inch barrel (cut rifling hand lapped) this time lapua brass, CCI 450 primers, IMR4451 (41. Rifling refers to the spiral grooves that are cut into the internal surface, known as the bore, of a gun barrel. "The most important part of such a gun - the rifling in the barrel - is in the Ballard the best yet produced. This recovered Hornady . Rifling cutter US2757580A (en) 1952-11-07: 1956-08-07. Limiting speed probably has to do with practical limitations on depth of cut and speed of cut, which in turn are probably more limited by chip removal than raw. Although our machines are state-of-the-art, the process itself is the oldest and slowest method of rifling a barrel. Button rifling is done by pulling a solid carbide forming die (referred to as a button) through the drilled and reamed barrel bore. This rifling-machine post will still be here when you come back). AC KRO GRUV is Mossberg version of marlins Microgroove ~~ MicroGroove Rifling [edit] Micro-Groove rifling. A mandrel is pushed or pulled through the bore and displaces material into the shape of rifling. Aug 27, 2011. The grooves are usually parallel in barrels while the sides of the lands are not. What is Button Rifling? In button rifling, the “button” is actually a tool made of tungsten carbide. 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. Rifling twist rate can be changed. Hero Member;. Marlin's Microgroove Barrels. At a practical level there is no difference as to the "extreme high quality, accuracy, and durability (lifespan)" of barrels made by CHF versus button rifled for AR15 type barrels. Single-point cut rifling, also sometimes called hook rifling, is not the most economical method, as it is very slow. 35 Remington microgroove rifled barrel. The cutter was a series of 4 or 5 "teeth" filed at about 30 degrees to the axis of the shaft. This process is done after there's a hole in the barrel blank. Broach cut rifling cuts all the grooves at the same time as the broach is pulled through the barrel. We proudly create rifle barrels for F-Class. Bear Creek Arsenal. This sets us separate from the other barrel maker's out there that drill with a stationary drill with the barrel rotating. One key element to also keep in mind is that cut rifled can be fluted without having to relap and heat treat the barrel unlike button rifled. He recently purchased a Pratt & Whitney Sine Bar Cut-Rifling barrel machine. I am looking to build up a lever . Many years ago,I was invited to watch button rifling being done. The bullet you want to shoot will determine your required barrel twist rate. Now them making 20mm, 25, 30 and up to 105mm they can do and if I recall correctly they do a form of cut rifling but they just cannot do small caliber stuff. GMX bullets shows rifling lands road over the top of the. The cost of the blank, of drilling the hole and of reaming and lapping are all extra. explain what the caliber of a gun is. Really very instructive! I have used this book very much during all the years I´ve been in the ML gunsmith`s business. However, unlike the antique rifling cutters, the hook cutters used to cut rifling on modern machines are ground with a positive rake, usually 5[degrees], and actually cut the barrel steel rather than simply scraping it. The lands and grooves create a unique pattern on the bullet casing that can be used to identify the gun from which the bullet was fired. On my 3 groove barrel you can clearly see the leading edges of the lands being eaten away at. The cut rifling process is exactly what it sounds like. The drawbar attaches to the worm wheel and to the rifling cutter with precision tapered cross pins. Bartlein Barrels is a manufacturer of precision cut-rifled barrels used for hunting, precision tactical shooting, and benchrest competition. Hammer forging is also known as the "Appel process" or cold forming. Take your rotary cutter apart. Normally expressed as the peak pressure in pounds per square inchWe rifle by the single-point cut-rifling process. This process is no longer common. The broaching tool is. Conversely, the scrape cutter has mu l ti-point cutters inset into the opposed sides that can scraped a minimal of two opposed grooves to all grooves at a time. Rifling can be. Square bottom CUT rifling to . With their painstakingly meticulous manufacturing process, Krieger Barrels ensures every barrel is made with supreme accuracy and precision in mind. 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. It stands apart from most modern barrels’ six lands configuration. Senior Member . 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. with the catch being that we were always talking about cut-rifling. In order to produce rifling similar. 6. So we are only cutting one groove at a time at an approx. methods - The size of a firearm barrel may be designated in different ways • The most common is to specify its caliber which. Cut Rifling Cut rifling is the oldest method of rifling a gun barrel. The first thing I did when I took the rifle out of the box was to weigh it and it was just barely over six pounds. Cal. Invented in N uremberg around 1520, the cut-rifling technique creates spiral grooves in the barrel by removing steel using some form of cutter. 640″ minimum – maximum dimension from the breech face (bolt face) to that point in the chamber that measures . Check out the GROOVES above. 16530 posts · Joined 2000. this single point cut rifling process requires a single cutter to make 120 individual cuts to accurately rifle each bore. 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. You will even find some loading books that say, cast bullets don't do well in MG barrels past about 1. 4. Pratt and Whitney then created rifling machines that would use a hydraulic ram to force a shaped carbide "button" ( actually a short rod) through the barrel. Electron discharge machining (EDM)The following types of rifling use similar processes as the ones aforementioned. The bore of a gun barrel with conventional rifling is etched with corkscrew-like cuts. The insert has a screw that locks the cutter rod in place. Cutters can be shortened (height) by a variety of means to create shallow cuts. Brophy's book on Marlins. Creating the spiral grooves is accomplished one of several ways. Cut-rifling is also the only practical way to rebore barrels. Rifling consists of spiral grooves cut into the inside of a barrel of a gun. These variables can give the unknowing shooter a false impression that one caliber or cartridge has superior life than another or one barrel manufacturer is superior than another’s. The twist is 1:12, bullet weighs 216-grains from an Accurate mould and a mv of about 1900 fps. #14 · Aug 14, 2021. #2. "Up until a couple years ago the PC 500 mags did indeed have Lothar Walther polygon rifling. * Cut-rifled barrels are drilled, then reamed to bore diameter. The sides of the grooves are parallel, but the sides of the lands are not and the 5R carries this to an extreme. Fairly sharp , (but not too sharp as to cut the patches) lands grip the best. Stone of Robbins & Lawrence created a rifling machine for carving out the barrels of guns, in particular the foreign-designed Enfield Rifles. Manuela. Using a small 1/8" chisel, carefully remove the wood from the inside the mortise to a depth of about 1/32" to 1/16". The most likely problem from button rifling is in skinny barrels which taper to a small. Maybe . It takes a LOT of effort to pull a . Double scrap cutter tooling was being used/made back even when the cut rifling was done manually by a human pulling the cutter thru the barrel by hand! Places have converted/modified the Pratt’s for pulling broaches and even pulling buttons. Then, grooves are cut, leaving the original hole's surface as. Rifling can be achieved as either a metal cutting, or cold forming process. Mark on the surface of a fired bullet made when the edges at the beginning of the rifling scrape the bullet surface or when the nose of the bullet slides on the surface of the forcing cone of a revolver barrel. A button does not cut. This method is used on most high-precision target barrels. Notice there are two headspace reference dimensions for the chamber. 6), and 140 eld-m average is 2715 Nearly a grain more in powder but 55fps slower. In general: 1) You're more likely to get an accurate twist rate with cut riflings than button riflings. Cutting metal from the bore produces rifling with fewer lands and grooves than pushing a tungsten carbide die through the bore which produces “button 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. $189. This process takes significantly longer than. 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. 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"). For a pistol, broach or button does an equally fine job. March 8, 2017. Rifling is the term for helical grooves machined into the internal surface of a firearms 's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. If you’ve never peered down a barrel to see what this may look like it is very square-cut; made at 90 ° angles. They varied a lot!Krieger Barrels has been making premium rifle barrels for over 30 years. Mar 6, 2006 2,869 2,608 CENLA. 1 deep. Broached rifling. Before 1950 all Marlin barrels were made by drilling the bore, and then cutting the rifling one groove at a time on a sine-bar machine. It is sometimes called "hook rifling" after the fishhook-shaped cutter used. In addition, the article describes a new (and somewhat radical) method, Cation Rifling, which employs acid to. Lands are the raised portions of the rifling that run down the inside of the gun barrel, while grooves are the cutouts in the rifling that run along the inside of the gun barrel. The rod should spin freely in its handle, and the jag and patch should fit snugly in your barrel. Current is applied and the “wet etching” process eats away metal in the desired areas to produced. Button rifling is simpler and faster than cut rifling and usually less expensive. A newer method of rifling barrels, called Electrochemical Rifling, does not involve the normal machining processes of the other techniques. 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. There are 5 different rifling methods, cut, button, broach, cold hammer forged and ECM. This sort of cutter design was used by gunsmiths for a very long time, all the way to about World War II. Broached Rifling -- This is done by cutting all grooves in a single pass using a special broaching bit with cutters that is inserted in the bore and. 001) per pass, so it is by and far the slowest (but most accurate) form of rifling. A spinning bullet is found to be more stable in its trajectory, and is therefore more accurate than a bullet that doesn’t spin. Gauging Equipment. On the other hand, many shooters believe cut-rifled barrels last a bit longer. It also work hardens the rifling. Rifling consists of spiral grooves cut into the inside of a barrel of a gun.