Readers who have just recently discovered the Daily Bulletin may not realize that AccurateShooter.com has hundreds of reference articles in our archives. These authoritative articles are divided into multiple categories, so you can easily view stories by topic (such as competition, tactical, rimfire, optics, shooting skills etc.). One of the most popular categories is our Technical Articles Collection. On a handy index page (with thumbnails for every story), you’ll find over 120 articles covering technical and gunsmithing topics. These articles can help you with major projects (such as stock painting), and they can also help you build more accurate ammo. Here are five popular selections from our Technical Articles archive.
Stress-Free Pillar Bedding. Richard Franklin explains how to do a top-quality bedding job, start to finish.
OnTarget Software Review. Our Editors test free software that measures shot groups with great precision. We explain how to use the program and configure advanced features.
Savage Action Tuning. Top F-TR shooter Stan Pate explains how to enhance the performance of your Savage rifle by optimizing the torque settings of the action screws.
Complete Precision Case Prep. Jake Gottfredson covers the complete case prep process, including brass weight sorting, case trimming, primer pocket uniforming, neck-sizing, and, case-neck turning.
Stock Painting Instructions. Step-by-step guide for stock painting by expert Mike Ricklefs. Mike shows both simple coverage and fancy effects.
How is a modern, metal-chassis rifle built? This very cool video from Masterpiece Arms answers that question. The nicely-edited video shows the creation of a Masterpiece Arms tactical rifle from start to finish. All aspects of the manufacturing process are illustrated: 3D CAD modeling, CNC milling of the chassis, barrel threading/contouring, chamber-reaming, barrel lapping, laser engraving, and stock coating. If you love to see machines at work, you will enjoy this video…
The last half-inch or so of your barrel is absolutely critical. Any damage (or abnormal wear) near the crown will cause a significant drop-off in accuracy. Here are ways you can check the end of your barrel, using a common Q-Tip.
Use Q-Tip for Barrel Inspection
To find out if you have a burr or damage to your crown, you can use an ordinary Q-tip cotton swab. Check the edges of the crown by pulling the Q-tip gently out past the edge of the crown. If you have a burr, it will “grab” the cotton and leave strands behind.
Larry Willis has another way to use a Q-Tip: “Here’s a neat trick that will surprise you with how well it works.” Just insert a Q-Tip into your barrel (like the picture below), and it will reflect enough light so that you can get a real good look at the last half inch of rifling and the crown of your barrel. In most cases you’ll find that this works much better than a flashlight. Larry tells us: “I’ve used this method about a jillion times. Q-Tips are handy to keep in your cleaning supplies anyway. This is a good way to judge approximately how well you are cleaning your barrel when you’re at the range. It’s also the best way to examine your barrel when you’re in the field.”
Sometimes you’ll get a barrel that doesn’t stabilize bullets the way you’d anticipate, based on the stated (or presumed) twist rate. A barrel might have 1:10″ stamped on the side but it is, in truth, a 1:10.5″ twist or even a 1:9.5″. Cut-rifled barrels, such as Kriegers and Bartleins, normally hold very true to the specified twist rate. With buttoned barrels, due to the nature of the rifling process, there’s a greater chance of a small variation in twist rate. And yes, factory barrels can be slightly out of spec as well.
After buying a new barrel, you should determine the true twist rate BEFORE you start load development. You don’t want to invest in a large supply of expensive bullets only to find that that won’t stabilize because your “8 twist” barrel is really a 1:8.5″. Sinclair International provides a simple procedure for determining the actual twist rate of your barrel.
Sinclair’s Simple Twist Rate Measurement Method
If are unsure of the twist rate of the barrel, you can measure it yourself in a couple of minutes. You need a good cleaning rod with a rotating handle and a jag with a fairly tight fitting patch. Utilize a rod guide if you are accessing the barrel through the breech or a muzzle guide if you are going to come in from the muzzle end. Make sure the rod rotates freely in the handle under load. Start the patch into the barrel for a few inches and then stop. Put a piece of tape at the back of the rod by the handle (like a flag) or mark the rod in some way. Measure how much of the rod is still protruding from the rod guide. You can either measure from the rod guide or muzzle guide back to the flag or to a spot on the handle. Next, continue to push the rod in until the mark or tape flag has made one complete revolution. Re-measure the amount of rod that is left sticking out of the barrel. Use the same reference marks as you did on the first measurement. Next, subtract this measurement from the first measurement. This number is the twist rate. For example, if the rod has 24 inches remaining at the start and 16 inches remain after making one revolution, you have 8 inches of travel, thus a 1:8″-twist barrel.
Determining Barrel Twist Rate Empirically
Twist rate is defined as the distance in inches of barrel that the rifling takes to make one complete revolution. An example would be a 1:10″ twist rate. A 1:10″ barrel has rifling that makes one complete revolution in 10 inches of barrel length. Rifle manufacturers usually publish twist rates for their standard rifle offerings and custom barrels are always ordered by caliber, contour, and twist rate. If you are having a custom barrel chambered you can ask the gunsmith to mark the barrel with the twist rate.
Wouldn’t it be cool if you could shoot .22 LR rimfire ammo from your regular hunting or tactical rifle? That would be ideal for low-cost training right? Well, this IS possible, provided you have a rifle that was designed with a .22 LR conversion in mind. One such firearm is the remarkable Sauer 202 from Germany. This impressive centerfire rifle is available with a factory-engineered .22 LR rimfire conversion. Read on to learn how Sauer’s cool .22 LR conversion works.
Sauer 202 Rifle: .308 Win/6.5×55 with .22 LR Conversion
Forum member “Tooms” sent us a report on his very special Sauer 202 with a .22 LR conversion kit. Sauer 202 rifles feature a “Quick-change barrel system”. The barrel is clamped into the receiver with crossbolts providing tension. This allows barrels to be swapped in a few minutes with simple tools. NOTE: This conversion kit was originally designed for the Sauer 200 STR, but because the Sauer 202 shares virtually the same design for the action/bolt/magazine, the system works for the 202 as well.
Tooms, from Denmark, explains: “The rifle began as a Sauer 202 Avantgarde Gold in .308 Win. I have added a 6.5×55 match barrel, plus a wide flat-bottom match fore-arm with rail for handstop and bipod. The .22 LR system [originally] cost $1000.00 [including] barrel, bolt, magazine well assembly, and magazine. The barrel is attached by three cross-bolts and the magazine well assembly is attached by one screw that fits into the barrel.”
Using this “Quick-change system”, Tooms can easily remove his centerfire barrel and swap in a .22 LR barrel. Then he places the factory conversion kit into the magazine well. This kit provides a rimfire bolt, a fitted sleeve for the rimfire bolt, and a magazine housing. This is a full Sauer factory-designed system so it works flawlessly. With the bolt closed, you can see the “new” .22 LR chamber in the front section of the loading port. On the silver section of the bolt you can see the rimfire extractor on the side.
The .22 LR Conversion Really Works
The Sauer 202 Varmint rifle shoots very well with the .22 LR conversion, as the 50m target at right shows. Though quite expensive, the conversion kit essentially transforms your centerfire rifle into fully functional, mag-fed precision rimfire rifle. That makes the Sauer 202 much more versatile as a hunting platform. It also allows you to cross-train with inexpensive ammo. You don’t have to purchase another scope, trigger, or stock. And you enjoy the exact same stock fit and ergonomics whether you’re shooting centerfire or rimfire. In some countries where gun ownership is severely restricted, it may be easier, from a legal standpoint, to purchase a .22 LR conversion kit than to obtain a permit for a second rifle.
Comments from Readers about .22 LR Conversions:
“I had a Sauer 200 STR with the .22 LR conversion and a .308 Win barrel kit. I can attest to the accuracy of both systems. The .22 LR would easily hold 1/2 MOA or better out to 100 yards. I now have the .22 LR conversion in my Sig SSG 3000 (same action as the Sauer 200TR and the Sauer 202 listed here). The action and trigger are as good as any I have ever used to include custom actions, AIAW, AIAT, TRG22. I never had 1 malfunction from the .22 LR over many thousands of rounds. They are truly top shelf systems!” — Jesse Bell
“Blaser made a .22 LR conversion kit for the R93 for a few years. It was available in 17 HMR, .22 LR, and .22 Magnum. My 17 HMR version has fired well over 17,000 rounds at prairie dogs and has scored kills in excess of 250 yards on many occasions. Possibly the best thing ever for practicing with your big game/match rifles.” — Captain Dave Funk
The Sauer 202 rifle line-up has been replaced by the Sauer 404 series which has much in common. To learn more about the complete line of Sauer rifles visit the J.P. Sauer USA website. You’ll also find more information on the primary J.P. Sauer & Sohn German website, www.Sauer.de. Though out of production, Sauer 202s can be found for sale on the used market.
Most modern match rifle barrels are stainless steel alloy. These are from Benchmark Barrels.
Though some grades of stainless are more corrosion-resistant, ALL varieties of stainless steel can rust if they are not handled and stored properly.
Some folks feel that they don’t have to worry about rust and corrosion on stainless steel barrels, actions, and other components. That’s not really true. “Stainless” is a bit of a misnomer. First, there are different types of stainless steel alloys, with different degrees of rust resistance. 300 series stainless is more corrosion resistant than the 416 stainless commonly used in barrels. The composition (by percentage weight) of 416 stainless is 0.15% carbon, 12-14% chromium and the rest iron. 416 stainless steel lacks the roughly 10% nickel content that makes the 300 series more corrosion resistant in atmospheric conditions. But because 416 handles pressure better and is easier to machine (than 300 series steel), 416 stainless remains the better choice for barrels.
Though some grades of stainless are more corrosion-resistant, ALL varieties of stainless steel can rust if they are not handled and stored properly. Forum reader Kells81 observed: “Wanna see some rusted stainless? Go to the big “C” brand store in Ft. Worth. Every stainless gun they have on the used gun rack is rusted.” Tom Easly of TRE Custom explains: “Sweat is very corrosive. Sweat and blood will rust many stainless steels. I hate to handle my guns or drip on them when I sweat. It really helps to just wipe them good with a wet rag, dry and wipe on a light coating of gun oil. I think most stainless barrels are made from type 416 stainless, and it is generally pretty corrosion resistant, but not when exposed to sweat, blood, or chlorates (corrosive priming), and some other electrolytes.”
Forum member Jacob, who is studying materials science at LSU, provides this technical information: “The basic resistance of stainless steel occurs because of its ability to form a protective coating on the metal surface. This coating is a ‘passive’ film which resists further ‘oxidation’ or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or other fluids that contain oxygen. Once the layer has formed, we say that the metal has become ‘passivated’ and the oxidation or ‘rusting’ rate will slow down to less than 0.002″ per year (0.05 mm per year).
Unlike aluminum or silver, this passive film is invisible in stainless steel. It’s created when oxygen combines with the chrome in the stainless to form chrome oxide which is more commonly called ‘ceramic’. This protective oxide or ceramic coating is common to most corrosion resistant materials.
Halogen salts, especially chlorides, easily penetrate this passive film and will allow corrosive attack to occur. The halogens are easy to recognize because they end in the letters ‘ine’. Listed in order of their activity they are: fluorine, chlorine, bromine, iodine, astatine.
These are the same chemicals that will penetrate Teflon and cause trouble with Teflon coated or encapsulated O-rings and/ or similar coated materials. Chlorides are one of the most common elements in nature and if that isn’t bad enough, they’re also soluble, active ions. These provide the basis for electrolytes. The presence of electrolytic solutions can accelerate corrosion or chemical attack.”
CONCLUSION: Stainless steel barrels and components won’t rust nearly as fast as blued steel, but you still have to take precautions — particularly removing sweat and corrosive salts from the barrel. Also, don’t let moisture build up inside or outside of the barrel. We recommend wiping your barrels and actions with Eezox, or Corrosion-X after each use. These are both extremely effective rust-fighters that go on thin, without leaving a greasy residue. (Eezox leaves a clear finish, while Corrosion-X has a slightly waxy finish.) Also store your guns in Bore-Store bags when the guns go in the safe. Bore-Stores wick away moisture, and the synthetic fleece inner surface is treated with rust-fighting chemicals. Bore-Stores also protect your guns against dings and scratches.
Enjoy the Shooting Sports USA Archives
As we head into spring, many Americans will be spending more time at the range. And competitors will be shooting in rimfire and centerfire rifle matches throughout the country. Here’s an opportunity to learn competition skills, gun tuning methods, and reloading techniques from leading experts. A vast resource of great gun-related content available online for FREE. Check out the Shooting Sports USA Articles Archive. SSUSA maintains a vast digital library with hundreds of articles going back to June 2009.
It’s easy to find back issues of Shooting Sports USA magazine. Here’s how: First, navigate to the latest SSUSA Online Issue (September 2025). Then click on the “ARCHIVES” icon in the upper right area (indicated with red arrow). When you click on “ARCHIVES”, a window will open with a selection of Shooting Sports USA magazine covers/dates in a vertical column. The most recent issue (August 2024) will appear at the top left. You can then scroll down — use the vertical scroll bar to go from September 2025 all the way back to June 2009. Click any issue cover to read.
How to Find and Save Articles
To search back issues, select “MORE OPTIONS” from the toolbar (top left). Then click the “SEARCH” button. When that opens, select either “Search Archives” for ALL back issues or “Search Only this Issue”. When you’ve made your choice, enter your search term(s). For example, you can search for “Camp Perry” or “Palma” or “F-Class Championship”. You can also save any archived issue as a PDF for viewing offline. Just click “SAVE” to download the article you’re currently viewing/reading.
Read Sample Articles
Here are a three of our favorite SSUSA feature stories from recent years. There are hundreds of other informative articles worth reading.
F-Class fans will enjoy the coverage of the 2023 F-Class World Championships in the June 2023 issue of Shooting Sports USA. On the cover is our friend and Forum member Erik Cortina. The 2026 F-Class World Championship will be held at the at the world-famous Stickledown range at the Bisley Camp in the UK
If two barrels are better than one, then why not three? That’s the thinking behind the exotic Bockdriling BD14 from Blaser, unveiled at the 2014 IWA Show in Germany. This three-barrel Bockdrilling firearm works as a shotgun, large-caliber rifle, and small-caliber rifle all in one. Even with all those barrels, the BD14 is relatively light, at 3.3 kg (7.26 lbs) without optics. That makes this a nice, carry-around gun for stalking. As you’d expect from Blaser, the twin triggers are crisp and precise, with a pull weight of just 1.43 lbs (650 grams). The front trigger is for the large-caliber rifle barrel, while the rear trigger works both the shotgun and small-caliber barrels, via a tang-mounted selector. These firearms are rare in the USA — and quite expensive. The only Blaser BD 14 we could find on GunBroker had a $9099.95 asking price. That works out to over three grand per barrel.
Here’s what Blaser USA has to say about its unique three-barreled BD 14:
“The ‘Bockdrilling’ is, put simply, an over/under (O/U) rifle-shotgun combination with a smaller caliber rifle-barrel… on the side. The barrel arrangement [allows] for an extremely slender receiver, making the BD14 exceptionally huntable.
The [patent-pending] Vertical Block Lockup… combines an extremely compact and solid block lockup in a closed system within the monoblock with the comfortable handling of a classic break-action rifle.
The double lock permits, if needed, a rapid second shot, the front trigger always releasing the large rifle-caliber. The … barrel selector actives the shotgun barrel when in position ‘top’ and activates the smaller rifle caliber in position ‘bottom’.”
Why Does Anyone Need Three Barrels?
The Blaser website explains: “As hunters, we learn to expect the unexpected, whether in a blind or stalking, so it’s understandable that we dream of a firearm that will allow us to take advantage of any situation. With the Bockdrilling BD14, Blaser has developed the perfect blind and stalking firearm – compromises are finally a thing of the past.”
Design Features of the Bockdrilling BD 14 Tri-Barrel Gun
The BD14 has a double-lock system so that a second shot can be taken without having to recock the firearm. Blaser says: “Thanks to the free-floating barrels, point of impact remains constant even with a quick succession of shots, no matter which barrel was fired first. The extremely strong vertical block lock on the BD14 helps contribute to the high degree of precision.”
Story idea from EdLongrange. We welcome reader submissions.
If you are looking to acquire a reliable, accurate rifle for a late fall hunt, Howa can be a good choice. Howas feature smooth-running actions with fine two-stage HACT triggers. A Howa barreled action can also be a good basis for a DIY project. But some folks have heard that it may be difficult to find stocks, or to fit an after-market barrel. That’s not true. There are many stock options available, and in this article, Bill of RifleShooter.com shows that it is easy to remove the factory-installed barrel with the right tools. We think a Howa makes a fine basis for a varmint rig or field rifle. Or you can build a tactical rifle as Bill did. You can start with the factory barrel and when you want/need more accuracy, then have a gunsmith install a custom barrel from Krieger Barrels, Lilja Barrels or other quality brand.
The Carbon Stalker is an excellent ultralight factory option, weighing just 4.6 lbs. with Mini Action (before optics). All Howa Carbon Fiber Stalker rifles come with a Sub-MOA Guarantee and Lifetime Warranty.
What You Need to Know About Howa 1500-series Rifles
Tech Feature by Bill, editor of RifleShooter.com
Consider this article the “Howa 1500 Overview”. There has been a lot of interest in Howa rifles and barreled actions imported by Legacy Sports International. In addition to being able to buy a complete rifle from a dealer, Brownells sells barreled actions in a wide variety of calibers and configurations. In this post we are going to take a look at the Howa 1500 series.
Howa Rifles — General Background
Howa is a Japanese heavy machinery company. One of its product lines are firearms, which are imported into the United States of America by two different companies, Legacy Sports International and Weatherby. Legacy sells the 1500 under the manufacturers name while Weatherby re-brands the guns as the Weatherby Vanguard. In general, the finishes on the Weatherby rifles are more refined than the LSI-imported 1500s.
General Evaluation of Howa 1500 Rifles
I’ve found Howa 1500s to be solid, entry-level rifles that are capable of sub-MOA accuracy out of the box. I’ve actually purchased two Howa rifles I’ve tested because I like them so much. The gun below, a Howa Mini-Action in 7.62×39 Russian, is one of my favorite factory guns to shoot.
Check out this three-shot group I drilled at 100 yards with the rifle above and 125-grain Sierras. It took a lot of work and load development to get there, but when it did, it worked well.
Howa 1500 HACT 2-Stage Trigger
Howa 1500s feature the very nice Howa HACT trigger. This is an adjustable, two-stage trigger, set for about 3 pounds (combined stages). Crisp and repeatable, this is an excellent trigger for a factory gun. There is no annoying Glock-style safety lever in the middle of the trigger blade. The 2-stage design and pull weight range works well for a hunting rifle or a rig for PRS competition. Rifleshooter.com says the Howa trigger is “one of the best factory triggers, along with Tikka. I’ve found the Howa trigger superior to a Remington 700 — the Howas doesn’t need to be replaced.”
Writing for the Western Outdoor News, WONews.com, Steve Comus has field-tested the HACT Trigger. Steve writes: “I always liked two-stage triggers, because of the way I could take-up the slack and then actually know when the rifle was going to go off. The take-up on the [HACT] trigger was fast and easy. The crisp, positive release when pressure was put on during the second stage [reminded me] of some of the target rifles I shot through the years.”
Howa Actions — Three Options
Howa offers three action lengths: Mini, Short, and Long. You can see the bolts for the three action lengths in the image below. The Mini-Action has similar external dimensions to the Remington Model Seven, however, the Mini-Action’s bolt does not travel as far to the rear. This is a mixed bag. The upside is you have a quicker action (shorter bolt throw). The downside is you are limited to shorter rounds such as the .223 Remington, 7.62×39mm Russian, and 6.5 Grendel. But if you need a bigger cartridge, just choose the standard or long action Howa variant.
Howa 1500 vs. Remington 700 — Important Differences
Is the Howa 1500 a Remington 700 clone, or some kind of improved Remington 700? No, not really. While the top radius of the Howa 1500 does match the Model 700, and they can both use the same two-piece scope bases, there are a number of differences.
If you look at the Howa 1500 alongside the Remington 700 you’ll note the M700 is a round action, while the Howa is a flat-bottom action. In many ways the Howa’s bottom half reminds me of a push-feed Winchester. This means the chassis and stocks that support a Howa 1500 are not V-block based like you’ll find on a 700, instead they have a flat bottom. While the bolt of the Howa is similar in external appearance to the Model 700, it does offer some improvements, notably an M16-style extractor and a firing pin assembly that can be easily removed without tools.
Howa 1500 action screws are metric and are in a different location from the 700. The Howa 1500 has an integral recoil lug that accepts the front action screw, this means you have more of the front action screw engaging the action. WARNING: If you install it into a poorly-fitted stock or action you may bind it.
Can a Howa Action Be Used for a Custom Rifle Project?
Absolutely! You can either buy a barreled action from Brownells and throw it in a chassis system/stock of your choice or you can use a stripped action to build a custom rifle. If you are in the chassis market, MDT offers a wide variety of chassis in different price ranges. All have worked well for me.
How to Remove Howa Factory Barrel from Action
You may have heard internet grumblings about removing Howa barrels. Some keyboard commandos say they are extremely difficult to remove without a relief cut. Well Bill at Rifleshooter.com demonstrates that Howa barrels can be removed without trouble, provided you have the right tools. Watch this video:
Watch Howa Barrel Removal Video — Quick and Easy (Click Speaker Icon for Audio)
Q: Is it difficult to remove a barrel from a Howa 1500?
A: Not very. I’ve heard from some smiths that worked on Howas (years ago) that the factory barrels are difficult to remove. However of the half dozen or so Howa barrels that I’ve pulled, they’ve been very easy. I use a Brownells action wrench with the top piece for a Rem Model 700 and the flat bottom resting against the flat on the wrench.
Howa Actions Require Metric Barrel Threads
It’s easy to thread a barrel for a Howa action. You just have to cut metric threads — most lathes out there can cut them. I cut the threads below on a manual lathe using change gears. [Editor: John Whidden cuts metric tenon threads with a CNC lathe. “It’s easy,” John tells us, “No issue whatsoever.”]
Using Howa Actions for Custom Rifles
I have built a few customs with Howa actions. Below is one of my favorite, a .308 Winchester. It consists of a Howa 1500 action, Shilen Select Match Rem Varmint contour barrel\, and Modular Driven Technologies (MDT) ESS chassis. Great rifle and it hammers!
Many barrel-makers mark the twist rate and bore dimensions on their barrel blanks.
Does muzzle velocity change with faster or slower barrel twist rates? Absolutely, but much less than you might think. Faster twist rates do slow down bullets somewhat, but the speed loss is NOT that significant. With Bartlein .308 Win barrels of identical length and contour, a 1:12″-twist barrel was only 8 fps faster than a 1:8″-twist barrel. That was the result of testing by Applied Ballistics.
The Applied Ballistics team tested six (6) same-length/same-contour Bartlein barrels to observe how twist rate might affect muzzle velocity. This unique, multi-barrel test is featured in the book Modern Advancements in Long Range Shooting, Vol. 1. That book includes other fascinating field tests, including a comprehensive chronograph comparison.
Barrel Twist Rate vs. Velocity — What Tests Reveal by Bryan Litz
When considering barrel twist rates, it’s a common belief that faster twist rates will reduce muzzle velocity. The thinking is that the faster twist rate will resist forward motion of the bullet and slow it down. There are anecdotal accounts of this, such as when someone replaces a barrel of one brand/twist with a different brand and twist and observes a different muzzle velocity. But how do you know the twist rate is what affected muzzle velocity and not the barrel finish, or bore/groove dimensions? Did you use the same chronograph to measure velocity from both barrels? Do you really trust your chronograph?
Summary of Test Results
After all the smoke cleared, we found that muzzle velocity correlates to twist rate at the average rate of approximately 1.33 FPS per inch of twist. In other words, your velocity is reduced by about 5 FPS if you go from a 1:12″ twist to a 1:8″ twist. — Bryan Litz
Savage Test Rifle with Six Bartlein Barrels
Most shooters don’t have access to the equipment required to fully explore questions like this. These are exactly the kinds of things we examine in the book Modern Advancements in Long Range Shooting, Vol. 1. In that book, we present experiments conducted in the Applied Ballistics lab. Some of those experiments took on a “Myth Buster” tone as we sought to confirm (or deny) popular pre-conceptions. For example, here’s how we approached the question of barrel twist and muzzle velocity.
Six .308 Win Barrels from Bartlein — All Shot from the Same Rifle
We acquired six (6) barrels from the same manufacturer (Bartlein), all the same length and contour, and all chambered with the same reamer (SAAMI spec .308 Winchester). All these barrels were fitted to the same Savage Precision Target action, and fired from the same stock, and bench set-up. Common ammo was fired from all six barrels having different twist rates and rifling configurations. In this way, we’re truly able to compare what effect the actual twist rate has on muzzle velocity with a reasonable degree of confidence.
Prior to live fire testing, we explored the theoretical basis of the project, doing the physics. In this case, an energy balance is presented which predicts how much velocity you should expect to lose for a bullet that’s got a little more rotational energy from the faster twist. In the case of the .30 caliber 175 grain bullets, the math predicts a loss of 1.25 fps per inch-unit of barrel twist (e.g. a 1:8″ twist is predicted to be 1.25 fps slower than a 1:9″ twist).
Above, data shows relationship between Twist Rate and Muzzle Velocity (MV) for various barrel twist rates and rifling types. From fast to slow, the three 1:10″ twist barrels are: 5R (canted land), 5 Groove, 5 Groove left-hand twist.
We proceeded with testing all 6 barrels, with twist rates from 1:8″ to 1:12″. After all the smoke cleared, we found that muzzle velocity correlates to twist rate at the average rate of approximately 1.33 fps per inch of twist. In other words, your velocity is reduced by about 5 fps if you go from a 1:12″ twist to a 1:8″ twist. [Editor: That’s an average for all the lengths tested. The actual variance between 1:12″ and 1:8″ here was 8 FPS.] In this case the math prediction was pretty close, and we have to remember that there’s always uncertainty in the live fire results. Uncertainty is always considered in terms of what conclusions the results can actually support with confidence.
This is just a brief synopsis of a single test case. The coverage of twist rates in Modern Advancements in Long-Range Shooting Vol. 1 is more detailed, with multiple live fire tests. Results are extrapolated for other calibers and bullet weights. Needless to say, the question of “how twist rate affects muzzle velocity” is fully answered.
Other chapters in the book’s twist rate section include: · Stability and Drag — Supersonic
· Stability and Drag — Transonic
· Spin Rate Decay
· Effect of Twist rate on Precision
Other sections of the book include: Modern Rifles, Scopes, and Bullets as well as Advancements in Predictive Modeling. This book is sold through the Applied Ballistics online store at thescienceofaccuracy.com. Modern Advancements in Long Range Shooting is also available as an eBook in Amazon Kindle format.
Readers who have just recently discovered the Daily Bulletin may not realize that AccurateShooter.com has hundreds of reference articles in our archives. These authoritative articles are divided into multiple categories, so you can easily view stories by topic (such as competition, tactical, rimfire, optics, shooting skills etc.). One of the most popular categories is our Technical Articles Collection. On a handy index page (with thumbnails for every story), you’ll find over 120 articles covering technical and gunsmithing topics. These articles can help you with major projects (such as stock painting), and they can also help you build more accurate ammo. Here are five popular selections from our Technical Articles archive.
The last half-inch or so of your barrel is absolutely critical. Any damage (or abnormal wear) near the crown will cause a significant drop-off in accuracy. Here are ways you can check the end of your barrel, using a common Q-Tip.
Sometimes you’ll get a barrel that doesn’t stabilize bullets the way you’d anticipate, based on the stated (or presumed) twist rate. A barrel might have 1:10″ stamped on the side but it is, in truth, a 1:10.5″ twist or even a 1:9.5″. Cut-rifled barrels, such as Kriegers and Bartleins, normally hold very true to the specified twist rate. With buttoned barrels, due to the nature of the rifling process, there’s a greater chance of a small variation in twist rate. And yes, factory barrels can be slightly out of spec as well.
The .22 LR Conversion Really Works
CONCLUSION: Stainless steel barrels and components won’t rust nearly as fast as blued steel, but you still have to take precautions — particularly removing sweat and corrosive salts from the barrel. Also, don’t let moisture build up inside or outside of the barrel. We recommend wiping your barrels and actions with Eezox, or Corrosion-X after each use. These are both extremely effective rust-fighters that go on thin, without leaving a greasy residue. (Eezox leaves a clear finish, while Corrosion-X has a slightly waxy finish.) Also store your guns in 
Howa 1500 HACT 2-Stage Trigger
