“Science tells us that exposure to continuous noise of 85 dB for eight hours is enough to cause permanent hearing loss, and worse, spikes of 130 dB and more can result in permanent hearing damage instantly.” Source: NRA Blog.
The Risk of Hearing Loss
Hearing loss can be progressive and irreversible. If you are a shooter, this is serious business. As the NRA Blog cautions: “You may not even realize you’re harming your hearing. Hearing loss occurs gradually, and can go effectively unnoticed until symptoms become severe. By then, the damage is done.”
Nobody wants to go deaf. But we often see shooters without effective hearing protection when they are walking around a few yards behind the firing line. That’s bad — even if you are away from the firing line, gunshot noises can damage your hearing. You MUST use effective hearing protection every time you go to the range. Good foam earplugs costs mere pennies but they can prevent deafness in your later years. Many folks also wear muffs over plugs.
Sound Levels for Common Noises:
9mm Luger pistol: 160 dB
Jet aircraft engine (near): 140 dB
.22 LR pistol: 134 dB
Normal human pain threshold: 120 dB
Noisy Nightclub: 110 db
Riding Motorcycle at 65 mph: 103 db
Power Lawnmower: 95 dB
Hearing damage possible: 85 dB (sustained for 8+ hours)
Ringing Telephone: 80 dB
Normal conversation: 60 dB
The Myth of the “Quiet” .22 LR
The NRA Blog notes that “many rimfire shooters, particularly those using the beloved .22 Long Rifle cartridge, argue that the small .22 LR caliber doesn’t produce enough sound to damage your hearing”. So, is that really true … or is it a myth?
In fact, a .22 LR can be much louder than you think — a .22 LR pistol can produce sound levels of 134 dB. That’s well above the normal human pain threshhold.
Highest Protection NRR 34dB-Rated Ear Muffs
For under $20.00 you can buy quality ANSI-approved muffs with a 34dB Noise Reduction Rating — the best you can get. Chose the Bright Yellow TR Industrial Muffs at $13.48, or the dark green Walker EXT Range Muffs for $15.42. Both products have padded head-bands which retract. Another dual-shell design with a 34dB NRR rating is the new FNova Muffs priced at just $13.22.
Howard Leight MAX NRR33 Earplugs, Just $7.98 for 50 Pairs.
20 Pairs
50 Pairs
These Howard Leight NRR33 Max plugs are your Editor’s favorite foam earplugs. Between shooting, motorcycling and mowing lawns, I probably have Max plugs in my ears 3-4 days a week. This is a very good price for a bulk pack of 50 pairs. And if you act soon, you can get free shipping to boot. This Editor just bought a 50-pack myself. And, yep, I got 50 pairs for $7.98 delivered, less than a pint of premium beer costs at my local pub:
This 2010 story is reprinted at readers’ request.
In the past few years, tubeguns have really taken over in high power circles. At most matches you’ll see more tubeguns than conventional prone rifles, and a high percentage of those tubeguns will have been built using an Eliseo (Competition Machine) CSS chassis kit.
Step-By-Step Guide to Stock Set-Up
If you are a new tubegun shooter, or if you are planning a tubegun build this winter, our friend “GS Arizona” has prepared a comprehensive set-up guide for Eliseo tubeguns. Eliseo’s CSS chassis system affords a myriad of adjustments. Initially, one can be overwhelmed by all the variables: Length of Pull, Length to Sights, Length to Handstop, Cheekpad Height, Buttstock Offset, Buttstock Cant Angle, Handstop Angle, and Forearm Rotation.
In his Guide to Configuring the Eliseo Tubegun, GS Arizona shows how to adjust the Tubegun so that a shooter’s prone position is stable, repeatable, and comfortable. The article covers each adjustment, step by step. If you follow the instructions, starting with setting Length of Pull, you should find that your hold becomes more stable, the gun moves less from shot to shot, and your eye position relative to the sights is improved.
About the Set-Up: “Adjusting the stock is a process that you must work at and it builds on itself. As you get one adjustment right, the others begin to fall into place. Our hope is that you take from this article a system for adjusting the stock, not an exact set of dimensions; and that you understand that it will take continuous work over a period of time to really refine the adjustments. Your goal is not to obtain a ‘perfect set of dimensions’ but rather a perfect feel that accomplishes the three objectives of stability, durability and comfort and the knowledge of how to change the adjustments to achieve those objectives under varying conditions such as sloped firing lines or other terrain features.”
High-Tech Rimfire Rigs
If you watched the smallbore position and prone shooters at the 2016 Brazil Olympic Games, you couldn’t help but notice the exotic rifles competitors were shooting. There were wood stocks, metal stocks, factory-built rifles and customized specials. Why are there are so many different design features and stock types? To answer this question, the NRAblog’s editors called on Jessie McClain of the NRA Competitive Shooting Division.
“The customized rifles, like the Anschütz you showed me, can make a real difference in a shooter’s performance,” explained McClain. “I went from a decent shooter to making the varsity shooting team my freshman year because of the rifle.” As Jessie explained, one new feature out there is the adjustable stock, which she called the Porsche of the shooting world. Fully adjustable from the butt plate to the check piece to the hand stop and risers and bolt knobs, this component is fully customizable to the athlete … which can be a huge advantage. “Every person is different … a customizable rifle fits anyone. A rifle team can purchase four of these and field a shooting team for years.”
The Modern Anschütz Position Rifle
Smallbore match rifle makers are using modern materials in response to the need for greater adjustability (and enhanced accuracy). One of the popular new designs is the Anschütz model 1913 position rifle with a “1918 ALU Precise” brushed aluminum stock. This looks like it has been crafted in an aircraft plant.
Probably the most popular centerfire rifle round in the Western Hemisphere is the .223 Remington and its metric match, the 5.56x45mm. Though many folks use “.223 Rem” and “5.56×45″ interchangeably, there are some meaningful differences in specifications for the original .223 Rem and the 5.56x45mm cartridge, as adopted by the U.S. military and NATO armies. The default chamber throats are slightly different and the .223 Rem is rated at 55,000 PSI vs. 62,366 PSI for the 5.56x45mm.*
.223 Rem vs 5.56x45mm — Key Differences
There is a truly outstanding, very thorough article on the subject, published by LuckyGunner.com.** This involved extensive testing, with pressure monitors, of 5.56x45mm ammo in .223 Rem chambers. Those tests revealed the peak pressures. Here is one of the ammo test charts:
NOTE: “The observed chamber pressure for Federal XM855 5.56mm ammunition in a .223 Rem chamber exceeded .223 maximum pressures, but not by a massive amount. The ninth shot (the red line) was an underpowered cartridge which exhibited significantly lower velocity and pressure than the other rounds, so it was excluded from the average velocity and pressure numbers for this chamber.”
And if you’re curious, LuckyGunner also fired .223 Rem ammo in a 5.56x45mm NATO-chambered AR15 rifle. As you would expect, the peak pressures were significantly lower, but the .223 Rem ammo still cycled the semi-auto AR-platform rifle perfectly well:
UltimateReloader.com Explains .223 Rem vs. 5.56x45mm
To explain the key differences between the .223 Rem and 5.56x45mm cartridges our friend Gavin Gear of UltimateReloader.com has created a very thorough 12-minute video. This covers the cartridge specifications and explains key considerations for hand-loaders. Gavin also addresses the oft-asked question “Can I shoot 5.56x45mm ammo in my .223 Rem chamber?” Gavin’s video is definitely worth watching. In fact, this is one of the most popular videos Gavin has ever created — it has been watched over 300,000 times on YouTube.
What Exactly Is the 5.56x45mm NATO Cartridge?
The 5.56×45mm NATO is a rimless bottle-necked intermediate cartridge family standardized by NATO with development work by FN Herstal. It consists of the SS109, SS110, and SS111 cartridges. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries.
Bullet diameter: 5.70 mm (0.224 in)
Maximum pressure (EPVAT): 430.00 MPa (62,366 psi)
Maximum pressure (SCATP 5.56): 380.00 MPa (55,114 psi)
Case length: 44.70 mm (1.760 in)
Rifling twist: 178 mm or 229 mm (1 in 7 in)
Parent case: .223 Remington (M193)
Ammo-Maker Federal Premium Compares .223 Rem and 5.56x45mm
Here is a video from ammo-maker Federal Premium explaining the difference between .223 Remington and 5.56x45mm NATO. Federal states that you may experience excessive pressures when firing a 5.56x45mm in a standard .223 Remington chamber:
One leading gunwriter has addressed the question of shooting 5.56x45mm ammo in .223 Rem chambers. He advocates caution (for more info, SEE pressure tests by LuckyGunner.com):
“I have received a slew of questions — many from first time AR-type rifle buyers — about the .223 Rem and the 5.56×45 mm NATO cartridges. Can I shoot 5.56×45 mm NATO in my .223 and vice-versa? Are these the same cartridge?
Externally, the two cartridge cases are identical. The main differences are that 5.56×45 mm NATO operates at a higher chamber pressure (about 60,000 PSI versus 55,000 PSI on the .223 Rem.) and the 5.56’s chamber is slightly larger than that of the .223 Rem. Also, the throat or leade is longer in the 5.56×45 mm chamber. What does this mean? You should not shoot 5.56×45 mm NATO out of a rifle that is chambered in .223 Rem. And be aware that some .223 Rem. ammunition will not reliably cycle through some AR-style .223 Rem. rifles, but it usually does. As a matter of fact, I have not encountered any difficulty with current .223 Rem. loads cycling through a 5.56 mm AR-style rifle.” – Mark Keefe, Editor, American Rifleman
* According to the official NATO proofing guidelines, the 5.56×45mm NATO case can handle up to 430.0 MPa (62,366 psi) piezo service pressure. The U.S. SAAMI lists Maximum Average Pressure (MAP) for the .223 Remington cartridge as 55,000 psi (379.2 MPa) piezo pressure with deviation of up to 58,000 psi (399.9 MPa). The chamber for military 5.56×45mm NATO has a longer throat prior to the bullet contacting the rifling which results in lower pressures when firing 5.56×45mm NATO ammunition. If 5.56×45mm NATO is used in rifles chambered for .223 Remington the bullet will be engraving the rifling when chambered. which can increase pressures past SAAMI Max levels. NOTE: The C.I.P. standards for the C.I.P. civilian .223 Remington chamber are much closer to the military 5.56×45mm NATO chamber.
** The full-length LuckyGunner article is well worth reading. It even provides specifications for a number of .223 Rem reamer types, and compares the original .223 Rem, the 5.56x45mm NATO, and the modern .223 Wylde chamberings.
Product innovation is all about “building a better mousetrap”, or in this case, building a better bore-cleaning patch. A real smart guy, Shane Smith, has invented a triangular patch that earned a patent. The U.S. Patent Office has awarded a utility patent for BoreSmith’s triangular Pyramid Patch™. This unique cleaning patch was designed by Shane Smith, a mathematician/physicist who employed his scientific and firearms knowledge to create innovative bore-cleaning products.
BoreSmith’s clever Triangle Patch™ (aka Pyramid Patch) presents more cleaning surface area to the bore wall than does a conventional square or round patch (of equivalent size). At the same time, the unique geometry makes Triangle Patches much less likely to jam in the barrel. This is because the notches in the sides of the triangle allow the patch to sit more uniformly on the jag (without bunching up). In addition, the Pyramid patch is must less likely to jam due to pleating. One reason conventional patches get stuck is unwanted 5-layer pleating. The special notches in the Pyramid patch remove all or most 5-layer pleating. As a result the patch does not bunch up and this also reduces rod bowing.
Triangle Patch Function and Geometry Explained (See 1:18 time-mark):
NOTE: Despite what you may see in this video, you should ALWAYS insert brushes and patches from the chamber end first, using a fitted cleaning rod bore guide. With bolt-action rifles, NEVER insert a cleaning rod (with brush or jag) in through the muzzle. This may damage the delicate crown of your barrel.
Do you have a family member who has recently acquired his or her first firearm? Do you have friends or neighbors who keep firearms in a home with small children? It is important to know and practice the principles of firearms safety, ALL the time. Here are two well-written gun safety manuals in printable PDF format. All firearms owners, even experienced hunters and competitors, can benefit from reviewing these resources from time to time. And new gun owners, in particular, should take the time to read both these guides. The Remington Safety Manual includes the “Ten Commandments of Firearms Safety”. Here’s the First Commandment:
Here’s a simple modification that makes your classic beam balance more user-friendly. For a few dollars you can enhance your balance scale system to improve work-flow and reduce eye strain. This clever modification makes it easier to see the balance’s zero-mark center-line when weighing charges.
When he chooses to measure his loads or sort bullets by weight, Forum Member Boyd Allen likes his trusty RCBS 10-10 scale. He finds that it works predictably, time after time, and it doesn’t suffer from the drift and calibration issues that plague some of the less-expensive electronic scales on the market.
To make it easier to see the balance point, Boyd has adapted a magnifying glass with a mirror. This makes the end of his balance beam easier to view from his normal position on the bench. Boyd explains: “This set-up uses a cheap magnifier with positioning arms that was probably designed to hold and magnify small objects while soldering them. I think that it came from Harbor Freight many years ago. The mirror lets you look at the scale as if is was at eye level, and of course the magnifier makes the image easier to see.”
What is “Overbore”? That’s a question rifle shooters can debate to no end. This article from our archives proposes one way to identify “overbore cartridges”. We think the approach outlined here is quite useful, but we know that there are other ways to define cartridges with “overbore” properties. Whenever we run this article, it stimulates a healthy debate among our readers — and that is probably a good thing.
Forum Member John L. has been intrigued by the question of “overbore” cartridges. People generally agree that overbore designs can be “barrel burners”, but is there a way to predict barrel life based on how radically a case is “overbore”? John notes that there is no generally accepted definition of “overbore”. Based on analyses of a wide variety of cartridges, John hoped to create a comparative index to determine whether a cartridge is more or less “overbore”. This, in turn, might help us predict barrel life and maybe even predict the cartridge’s accuracy potential.
John tells us: “I have read countless discussions about overbore cartridges for years. There seemed to be some widely accepted, general rules of thumb as to what makes a case ‘overbore’. In the simplest terms, a very big case pushing a relatively small diameter bullet is acknowledged as the classic overbore design. But it’s not just large powder capacity that creates an overbore situation — it is the relationship between powder capacity and barrel bore diameter. Looking at those two factors, we can express the ‘Overbore Index’ as a mathematical formula — the case capacity in grains of water divided by the area (in square inches) of the bore cross-section. This gives us an Index which lets us compare various cartridge designs.”
OVERBORE INDEX Chart
So what do these numbers mean? John says: “My own conclusion from much reading and analysis is that cartridges with case volume to bore area ratio less than 900 are most likely easy on barrels and those greater than 1000 are hard on barrels.” John acknowledges, however, that these numbers are just for comparison purposes. One can’t simply use the Index number, by itself, to predict barrel life. For example, one cannot conclude that a 600 Index number cartridge will necessarily give twice the barrel life of a 1200 Index cartridge. However, John says, a lower index number “seems to be a good predictor of barrel life”.
John’s system, while not perfect, does give us a benchmark to compare various cartridge designs. If, for example, you’re trying to decide between a 6.5-284 and a 260 Remington, it makes sense to compare the “Overbore Index” number for both cartridges. Then, of course, you have to consider other factors such as powder type, pressure, velocity, bullet weight, and barrel hardness.
Overbore Cases and Accuracy
Barrel life may not be the only thing predicted by the ratio of powder capacity to bore cross-section area. John thinks that if we look at our most accurate cartridges, such as the 6 PPC, and 30 BR, there’s some indication that lower Index numbers are associated with greater inherent accuracy. This is only a theory. John notes: “While I do not have the facilities to validate the hypothesis that the case capacity to bore area ratio is a good predictor of accuracy — along with other well-known factors — it seems to be one important factor.”
MagnetoSpeed’s technology has completely changed the market for firearms chronographs. With a MagnetoSpeed barrel-mounted chrono you can quickly and easily record muzzle velocity (MV) without having to set up tripods or walk down-range. The compact MagnetoSpeed chronos are easy to set up and transport. With the full-featured V3 model, everything you need comes in a small fitted case. In the top photo are the components used with the MagnetoSpeed V3 Kit:
1. V3 Bayonet sensor
2. Display and control unit
3. Bayonet spacers (plastic and rubber)
4. Cords and mounting hardware (left), suppressor heat shield (right)
5. Alignment rod (square cross-section)
6. Rail adapter (sold separately)
Our friend Gavin Gear of UltimateReloader.com recently reviewed the MagnetoSpeed V3 and came away impressed. Gavin explains the a good chrono is essential: “If you want to load and shoot precision ammunition, you need the tools that will produce and validate the precision of your loads. A good chronograph is one of those tools! In this post I’m going to introduce you to the MagnetoSpeed V3 chonograph, the high-end electromagnetic chronograph which fills out the top slot in MagnetoSpeed’s equipment portfolio.”
In this 11-minute video Gavin reviews MagnetoSpeed’s top-of-the-line V3 Chronograph. He shows what ships with the unit, how to set it up for both rifles and pistols, and then he puts it through its paces showing how it captures velocity data. Gavin says he will follow-up with future videos showing how to link the MagnetoSpeed V3 to your mobile phone and how to log velocity data for future reference. To learn more about this high-tech chrono, visit UltimateReloader.com.
In discussions of ballistics, you’ll see references to “tangent”, “secant”, and “hybrid” bullet shapes. We know that, for many readers, these terms can be confusing. To add to the confusion, bullet makers don’t always identify their projectiles as secant or tangent designs. This article provides a basic explanation of tangent, secant, and hybrid ogive bullet designs, to help you understand the characteristics of these three basic bullet shapes.
Tangent vs. Secant vs. Hybrid
Most match bullets produced today use a tangent ogive profile, but the modern VLD-style bullets employ a secant profile. To further complicate matters, the latest generation of “Hybrid” projectiles from Berger Bullets feature a blended secant + tangent profile to combine the best qualities of both nose shapes. The secant section provides reduced drag, while the tangent section makes the bullet easier to tune, i.e. less sensitive to bullet seating depth position.
Berger Bullets ballistician Bryan Litz explains tangent and secant bullet ogive designs in a glossary section of his Applied Ballistics website, which we reprint below. Bryan then explains how tangent and secant profiles can be combined in a “hybrid” design.
How Bullet Ogive Curves are Defined
While the term “ogive” is often used to describe the particular point on the bullet where the curve reaches full bullet diameter, in fact the “ogive” properly refers to the entire curve of the bullet from the tip to the full-diameter straight section — the shank. Understanding then, that the ogive is a curve, how is that curve described?
LITZ: The ogive of a bullet is usually characterized by the length of its radius. This radius is often given in calibers instead of inches. For example, an 8 ogive 6mm bullet has an ogive that is a segment of a circular arc with a radius of 8*.243 = 1.952”. A .30-caliber bullet with an 8 ogive will be proportionally the same as the 8 ogive 6mm bullet, but the actual radius will be 2.464” for the .30 caliber bullet.
For a given nose length, if an ogive is perfectly tangent, it will have a very specific radius. Any radius longer than that will cause the ogive to be secant. Secant ogives can range from very mild (short radius) to very aggressive (long radius). The drag of a secant ogive is minimized when its radius is twice as long as a tangent ogive radius. In other words, if a tangent ogive has an 8 caliber radius, then the longest practical secant ogive radius is 16 calibers long for a given nose length.”
Bryan Litz Explains Hybrid Design and Optimal Hybrid Seating Depths
Ogive Metrics and Rt/R Ratio
LITZ: There is a number that’s used to quantify how secant an ogive is. The metric is known as the Rt/R ratio and it’s the ratio of the tangent ogive radius to the actual ogive radius for a given bullet. In the above example, the 16 caliber ogive would have an Rt/R ratio of 0.5. The number 0.5 is therefore the lowest practical value for the Rt/R ratio, and represents the minimum drag ogive for a given length. An ogive that’s perfectly tangent will have an Rt/R ratio of 1.0. Most ogives are in between an Rt/R of 1.0 and 0.5. The dimensioned drawings at the end of my Applied Ballistics book provide the bullets ogive radius in calibers, as well as the Rt/R ratio. In short, the Rt/R ratio is simply a measure of how secant an ogive is. 1.0 is not secant at all, 0.5 is as secant as it gets.
Hybrid Bullet Design — Best of Both Worlds?
Bryan Litz has developed a number of modern “Hybrid” design bullets for Berger. The objective of Bryan’s design work has been to achieve a very low drag design that is also “not finicky”. Normal (non-hybrid) secant designs, such as the Berger 105gr VLD, deliver very impressive BC values, but the bullets can be sensitive to seating depth. Montana’s Tom Mousel has set world records with the Berger 105gr VLD in his 6mm Dasher, but he tells us “seating depth is critical to the best accuracy”. Tom says a mere .003″ seating depth change “makes a difference”. In an effort to produce more forgiving high-BC bullets, Bryan Litz developed the hybrid tangent/secant bullet shape.
The Risk of Hearing Loss
In his 
High-Tech Rimfire Rigs
Hybrid Bullet Design — Best of Both Worlds?
