Christmas Day is just 13 days away. We know many of our readers and Forum members will be traveling to spend the holidays with friends and families. If you will be transporting any firearms when traveling by air over the holidays you need to know the rules.
If you will be flying with firearms this holiday season, you should read this article. You need to familiarize yourself with current Federal Regulations on gun transport before you get anywhere near an airport. Thankfully, the Transportation Security Administration (TSA) has a web page that states the important requirements for airline passengers traveling with firearms and/or ammunition.
You’ll want to visit the TSA Firearms and Ammunition webpage, and read it start to finish. In addition, before your trip, you should check the regulations of the airline(s) with which you will fly. Some airlines have special requirements, such as weight restrictions.
Here are the TSA’s key guidelines for travel with firearms:
TSA FIREARM Guidelines
1. When traveling, comply with the laws concerning possession of firearms as they vary by local, state and international governments.
2. If you are traveling internationally with a firearm in checked baggage, please check the U.S. Customs and Border Protection website for information and requirements prior to travel.
3. Declare each firearm each time you present it for transport as checked baggage. Ask your airline about limitations or fees that may apply.
4. Firearms must be unloaded and locked in a hard-sided container and transported as checked baggage only. As defined by 49 CFR 1540.5, a loaded firearm has a live round of ammunition, or any component thereof, in the chamber or cylinder or in a magazine inserted in the firearm. Only the passenger should retain the key or combination to the lock unless TSA personnel request the key to open the firearm container to ensure compliance with TSA regulations. You may use any brand or type of lock to secure your firearm case, including TSA-recognized locks.
5. Bringing an unloaded firearm with accessible ammunition to the security checkpoint carries the same civil penalty/fine as bringing a loaded firearm to the checkpoint. You may find information on civil penalties at the Civil Enforcement page.
6. Firearm parts, including magazines, clips, bolts and firing pins, are prohibited in carry-on baggage, but may be transported in checked baggage.
7. Replica firearms, including firearm replicas that are toys, may be transported in checked baggage only.
8. Rifle scopes are permitted in carry-on and checked baggage.
TSA Ammunition Guidelines
1. Ammunition is prohibited in carry-on baggage, but may be transported in checked baggage.
2. Firearm magazines and ammunition clips, whether loaded or empty, must be securely boxed or included within a hard-sided case containing an unloaded firearm. Read the requirements governing the transport of ammunition in checked baggage as defined by 49 CFR 175.10 (a)(8).
3. Small arms ammunition (up to .75 caliber and shotgun shells of any gauge) must be packaged in a fiber (such as cardboard), wood, plastic, or metal box specifically designed to carry ammunition and declared to your airline.
4. Ammunition may be transported in the same hard-sided, locked case as a firearm if it has been packed as described above. You cannot use firearm magazines or clips for packing ammunition unless they completely enclose the ammunition. Firearm magazines and ammunition clips, whether loaded or empty, must be boxed or included within a hard-sided, locked case.
5. Please check with your airline for quantity limits for ammunition.
More Airline Travel Tips from Tom McHale
A while back, Tom McHale wrote an excellent article for the Beretta Blog, entitled Ten Things You Need to Know about Flying with Guns. Here are two of Tom McHale’s Travel Tips from that article:
Weigh your gun case and ammunition
Most airlines will allow up to 11 pounds of ammunition. And, like any luggage, you will be charged more for any baggage weighing more than 50 pounds. This sounds like a lot, but when traveling to the Crimson Trace Midnight 3 Gun competition last year, my case with shotgun, rifle, pistol and ammunition tipped the scale past the 50 pound mark.
Pack ammo in the same locking case
This is another area that’s misunderstood and full of internet myth. Your ammo just needs to be stored in some type of safe container and not loose. Technically, you can keep ammunition in magazines, but I wouldn’t recommend it. It meets the letter of the law storage requirement, but too many airline and TSA agents will give you grief. Use a plastic ammo box or original cardboard packaging and you’ll be fine carrying that in the same lockable case as your gun.
*Please see, United States Code, Title 18, Part 1, Chapter 44 for information about firearm definitions.
Who hasn’t dreamed of having a professional-quality, permanent shooting bench on their own property? Well here’s an article that can help you make that dream come true. This “how-to” feature from the archives of RifleShooter Magazine shows how to build a quality concrete shooting bench step-by-step.
All aspects of the construction process are illustrated and explained. The author, Keith Wood explains: “Construction happened in three phases — first creating the slab foundation, then the support pillars (legs), and finally the table.”
Click image below to load article with slide show.
Each step in the process is illustrated with a large photo and descriptive paragraph. Starting with framing the foundation (Step 1), the article illustrates and explains the 15 Steps that produce the finished, all-concrete bench (see top photo).
Winter solstice — December 21, 2025 — is ten days away. We’re seeing extremely cold temperatures throughout many northerly states, with lots of snow falling on the ground. And some very cold weather is predicted this coming weekend. For American firearms fans in those colder climes, indoor training is the only realistic option this time of year.
AccuWeather forecasters warn that very cold temperatures with significant snowfall will hit the Northeast in the next few days. CLICK HERE for Accuweather Weather Report.
This article explains some key points to remember when shooting at indoor ranges. Always remember — safety first. Be especially careful to follow ALL the rules of safe gun handling. And even before you get to the range, make sure your guns are transported safely and in compliance with all local laws. In some states firearm(s) and ammunition must be kept in separate containers during transport.
This Video Covers Basic Gun Range Safety Rules and Etiquette
FIVE IMPORTANT SAFETY PROCEDURES for Indoor Ranges
1. Follow the Three Fundamental Rules for Safe Gun Handling
ALWAYS keep the gun pointed in a safe direction. ALWAYS keep your finger off the trigger until ready to shoot. ALWAYS keep the gun unloaded until ready to use.
2. Follow ALL Range Officer Instructions
ROs are the first and final authority on any range and their decisions are generally final. Arguing with a Range Officer may just get you thrown out.
3. Don’t Bother Others or Touch Their Guns
Respect other shooters’ privacy unless a safety issue arises. Do NOT engage other shooters to correct a perceived safety violation unless absolutely necessary – inform the RO instead. NEVER handle or touch another shooter’s firearm without their permission!
4. Know Your Range’s Rules
Review and understand any and all range rules and requirements/expectations. For example, what is the range’s maximum rate of fire? Are you allowed to collect your brass?
5. Know What To Do During a Cease Fire
IMMEDIATELY set down your firearm, pointed downrange, and STEP AWAY from the shooting booth (or bench). Range Officers do not want shooters trying to “secure/unload” their firearms in a cease fire situation — they want the shooters separated from their guns instantly.
BAD RANGE BEHAVIOR — Five Things NOT to Do at the Range
Here are the five worst behaviors we’ve seen at indoor ranges. These behaviors are both dangerous and inconsiderate. Any one of these behaviors can get you permanently banned from an indoor range.
1. Sweeping other individuals after loading a weapon behind the firing line is very bad. All your weapons should be empty until you reach your shooting station.
2. Turning the handgun sideways while trying to clear a malfunction or insert/remove a magazine. This will point the muzzle at a fellow shooter. Or, after shooting a gun, the shooter fails to clear the weapon and then places the gun somewhere near the shooting station with the muzzle in an unsafe position.
3. Reacting unpredictably when firing a high recoil handgun. We’ve seen people take a second shot by accident with the muzzle way off target.
4. Not obeying range commands — in particular continuing to shoot during called cease-fires.
5. Poorly aimed shooting that hits target frames or carriers, causing ricochets.
Double-Up on Hearing Protection When Shooting Indoors
When shooting indoors we recommend quality muffs with earplugs underneath, offering double protection. When inside an enclosed range, with other shooters blasting away right next to you, you really need effective hearing protection. But you also need to hear range commands and be able to communicate. That’s why we recommend electronic muffs with plugs underneath.
For indoor rifle and pistol shooting, we like the latest Howard Leight Leightning L3 Ear Muffs. These offer an outstanding 30 dB Noise Reduction Rating (NRR). In addition, these muffs are pretty comfortable. These muffs are now $32.99 at MidwayUSA (great deal) and $37.41 on Amazon with FREE Delivery.
“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.”Effective hearing protection is a must whenever you are shooting firearms or when you are in the vicinity of gun-shots. For ultimate protection, we recommend a good set of tapered foam earplugs, topped by ear-muffs. However, there are situations when you may prefer lighter-weight hearing protection that can be quickly removed. For example, if you are standing well behind the firing line as an observer, or if you are working as a rangemaster or waddie some distance away from the shooters.”
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
What about suppressors? If you use a suppressor is it OK to dispense with hearing protection? Not really. Even the most effective suppressors, on the smallest and quietest calibers (.22 LR), reduce the peak sound level of a gunshot to between 110 to 120 dB. To put that in perspective, according to the National Institute for Occupational Safety and Health (NIOSH), that is as loud as a jackhammer (110 dB) or an ambulance siren (120 dB). For normal caliber handguns and rifles, suppressed sound levels routinely exceed 130 dB, just shy of OSHA’s “hearing safe” threshold of 140 dB. Accordingly, we recommend use of hearing protection even when shooting suppressed.
1. Ear Muffs — Max Protection and Compact Options
The highest current USA Noise Reduction Rating is 34 dB NRR. To get that kind of protection, you need pretty big muffs, but thankfully, you don’t have to spend big bucks. For under $15.00 you can buy quality ANSI-approved muffs with a 30+ dB Noise Reduction Rating. Chose the big 34 NRR G&F Pro Muffs at $15.99 or the more comfortable 30 NRR Walker EXT Range Muffs for $14.97. Both products have padded head-bands which retract.
Many hunters and competitive shooters prefer low-profile ear muffs. As these typically have a lower Noise Reduction Rating, perhaps NRR 22-24, we recommend running earplugs under muffs, particularly when you are at a busy range or shooting a match. If you use low-profile electronic muffs, such as Howard Leight Impact Sport Muffs, you should still be able to hear range commands even with plugs underneath.
If you need to talk to your shooting buddies or hear range commands during matches, there are a variety of good electronic muffs on the market. Some of these even have “Walkie-Talkie” functionality so you can talk to team-mates or coaches at matches. We like these 2-way electronic muffs, but be aware that they offer much less max noise protection — typically in the NRR 20-22 range. Here is a good deal currently at MidwayUSA for Walker Electronic Muffs with Walkie-Talkie functionality. This NRR 20-rated unit has slim pads with removable microphone unit. It is now on sale at a 55% discount.
2. Foam Earplugs — Small, Inexpensive, But VERY Effective
Quality foam earplugs offer great hearing protection at low cost. 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. These Leight Max plugs are very effective, easy to insert/remove (with the flared ends), and they seem to be less abrasive in the ear canal than some other brands. Right now you can get 20 pairs of these NRR33 Leight Max plugs for just $8.41.
If you prefer thin, light-weight earmuffs, we do recommend running earplugs underneath for double protection while shooting firearms (or when you’re on the firing line). Sound experts tell us that running plugs and muffs together can improve your effective noise reduction by 4-7 dB NRR.
Howard Leight MAX NRR 33 Earplugs, Just $8.41 for 20 Pairs
Hearing bands are inexpensive, lightweight, and are handy for special situations, such using hedgetrimmers and noisy power tools, when you may need to frequently remove the protection. These banded products are a also a very good form of hearing protection for hunters. You can keep them handy around the neck while spotting game, and then insert the plugs before shooting. We have tried two types of banded hearing protection, the Howard Leight QB2 Quiet Band (shown above) (25 dB NRR), and the Radians Rad-Band (23 dB NRR). The Leight Quiet Band is quite durable and the plugs can be replaced. It is a bargain at just $5.44 from MDI Safety.
Radians Rad-Band is very light-weight, with Jelli™ Plugs that are comfortable, washable, and reusable — all for just $12.13 on Amazon. Peltor also offers Sport Banded Earplugs. These conveniently ship with 3 pairs of ear buds, all for $11.99 on Amazon.
4. Electronic Plugs — New Technology with Adjustable Volume
For maximum hearing protection we still recommend good muffs over quality foam ear plugs, there is a new option available. A variety of companies now offer electronic ear buds that include small speakers so you can hear range commands and conversations. Please note — these MUST be specially-designed protective in-ear devices. Do NOT just use ear-buds designed for music playback!
Howard Leight recently introduced new Impact Sport In-Ear plugs with an impressive 29 dB Noise Reduction Rating (NRR). That NRR is better than most compact ear muffs. The plugs automatically compress amplification when loud impulse sounds (like gunshots) exceed 85dB. Internal amplification allows you to hear range commands and conversations. The cord connecting the plugs includes twin, handy volume controls. These plugs come with moldable earhooks with 3 different ear tip sizes. The deluxe model with quick-connect BlueTooth is available for $89.98 on Amazon. With this high-tech BlueTooth version you can take phone calls.
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Sierra BulletsBallistic Technician Gary Prisendorf has written a nice essay about how reloading can become a life-time hobby, a rewarding pastime that can bring together a father and son…
Memories of My Father — Reloading As a Life-Time Hobby
by Gary Prisendorf
For as long as I can remember I have been around reloading. I have tons of childhood memories of my father reloading and shooting. I remember how he would let me help him load his ammunition, by letting me clean primer pockets or wipe the sizing lube off of his cases. I really thought I was doing something. Well, I guess I was, I was spending quality time with my father doing something that would become a great hobby and eventually land me a great job working for Sierra Bullets.
If you are a reloader, teach someone. You may just give them a hobby for the rest of their life and who knows, you could help them find an enjoyable career, doing something that they love.
— Gary Prisendorf
I remember watching my father sizing cases on his Herters press, dropping his powder charges with a Belding & Mull powder measure and weighing powder charges with his Texan scales. Heck, I can even remember when he would buy powder at a local pawn shop, and they would weigh it out and put it in a paper sack. He would save his empty powder cans, wrap them with masking tape and write what the powder was on them with a black magic marker.
When I was in Junior High, I got my first shotgun, a 20 gauge Mossberg 500 and within a couple of weeks my father came home with a 20 gauge Lee Load-All and a pound of Blue Dot. He gave me a crash course on how to use it, and got me up and running with a couple of safe loads. I put a lot of shells through that old 20 gauge.
From that day forward I was hooked. If I got a new gun, I was loading ammunition for it. I don’t buy factory ammunition unless I just want to shoot it up so I can get some once fired brass. I reload everything that I shoot, except for rimfire stuff, and if I could figure out how to do that safely, I would probably load that too.
Through the years I have learned to appreciate things — such as once-fired military .30-06 cases that can be converted to obscure cartridge types. And I know the value of a five-gallon bucket of lead wheel weights that will be melted down and cast into bullets.
I remember finding 19 once-fired Norma 7.7×58 Arisaka cases laying on the ground at a public shooting range, and it was like Christmas came early. I must have looked for that 20th case for about thirty minutes, but I never did find it.
I can’t thank my father enough for getting me started in reloading, he gave me a great hobby, many wonderful memories and taught me the skills that gave me a career doing something that I love.
Forum member Erik Cortina has produced a series of YouTube videos about reloading hardware and precision hand-loading. Here we feature Erik’s video review of the Forster Co-Ax® reloading press. The red-framed Co-Ax is unique in both design and operation. It boasts dual guide rods and a central handle. You don’t screw in dies — you slide the die lock ring into a slot. This allows dies to float during operation.
Erik does a good job of demonstrating the Co-Ax’s unique features. At 1:00 he shows how to slide the dies into the press. It’s slick and easy. At the two-minute mark, Erik shows how sliding jaws clasp the case rim (rather than a conventional shell-holder). The jaws close as the ram is raised, then open as it is lowered. This makes it easy to place and remove your cases.
At the 5:20 mark, Erik shows how spent primers run straight down into a capture cup. This smart system helps keep your press and bench area clean of primer debris and residues.
While many Co-Ax users prime their cases by hand, the Co-Ax can prime cases very reliably. The priming station is on top of the press. Erik demonstrates the priming operation starting at 4:20.
Smart Accessories for the Co-Ax from Inline Fabrications
Forum member Kevin Thomas also owns a Co-Ax press, which he has hot-rodded with accessories from Inline Fabrication. Kevin tells us: “Check out the add-ons available from Inline Fabrication for the Co-Ax. I recently picked up a riser mount and a set of linkages for mine and love the results. The linkages are curved. When you replace the original straight links with these, the work area opens up substantially and the the press becomes much easier to feed.” CLICK HERE for Co-Ax Accessories.
Inline Fabrications Forster Co-Ax Accessories
Forster Co-Ax Curved Side Linkage (For Better Access)
“December 7, 1941, a date which will live in infamy…”
Today, 84 years later, it remains important to remember what took place at Pearl Harbor, and to honor those soldiers, sailors, marines (and civilians) who lost their lives in the surprise attack. The tragic memory of Pearl Harbor reminds us that our nation should never be lulled into complacency. The world remains a dangerous place. The nation must remain alert to all dangers, and be prepared to respond to all threats, both known and unknown. As Wendell Phillips said famously: “Eternal vigilance is the price of liberty.”
The Shooting Wire noted: “Today, as we live in another period of uncertainty … we owe our lives and success as a nation to the more than 16 million Americans who left their homes and traveled over the world to protect freedom.” According to U.S. Department of Veterans Affairs, there are fewer than 66,000 American World War II veterans alive today. That’s less than half of one percent of the 16 million Americans who served in World War I. Today, it’s appropriate to remember all the veterans who served in WWII and the sacrifices they made for us.
This Editor’s father and uncle both fought in WWII, father in the U.S. Army, uncle in the U.S. Navy. A Lieutenant in the Corps of Engineers, my father took part in three landings — North Africa, Sicily, and the south of France. I still have his invasion armband — a treasured memento. Sadly, we lost my uncle in 2019, when he died at age 100. While in the Pacific, he served at the Tulagi Navy Base, where he knew Lt. (JG) John F. Kennedy. Of Kennedy, my uncle told me: “Jack? He was a good kid… and he loved his country.”
Thoughts on Pearl Harbor, by Dennis Santiago
When I think of December 7th, I remember it is the day my elders began the most difficult four years of their lives. I have seen in their eyes the fear, anger and resolve that come from experiencing what it was like to survive in territory occupied by the Empire of the Rising Sun. My mother had never heard of Pearl Harbor. For her, World War II began on the same day seeing the Japanese bomb a U.S. naval installation called Cubi Point, at the entrance to Manila Bay in the Philippine Islands.
My maternal grandfather never spoke of what horrors he had seen on the Bataan Death March or his years in the prison camps. When I look at my father, I think of my other grandfather’s memories of his son — my father — hanging off the side of a Japanese patrol boat in Subic Bay with an Arisaka pointed at him, forced to give up the catch needed to feed his family….
Time has passed but the poignancy has not faded. Each December 7th, I’m thankful my elders survived because I would not be here to muse about it, had they not. The echoes of their ordeal drive me deeply to make sure that such a thing will never happen again. Whether called the Greater East Asia Co-Prosperity Sphere or some other name made up by the contemporaries of my day, the evil that lurks underneath those who believe their ideas justify the horrors they impose must always be confronted and defeated.
In June 2020, Hornady introduced the 6mm ARC, a new SAAMI cartridge optimized for AR-platform rifles*. The new 6mm ARC is basically a 6.5 Grendel necked down to 6mm, with the shoulder moved back around .030″. That pushed-back shoulder does reduce case capacity (and velocity), but we assume Hornady did that to create a shorter, proprietary chamber so people could not simply neck-down Lapua 6.5 Grendel brass, as has been done for years with Robert Whitley’s outstanding 6mm AR wildcat.
What Is the 6mm ARC Cartridge? The 6mm ARC cartridge is a new SAAMI-spec cartridge based on the 6.5 Grendel case necked down for 6mm bullets, with the shoulder moved back 0.030. Yes it is designed to run in AR15-platform rifles. You’ll need a new barrel, bolt, and mags. If you already have an AR chambered in 6.5 Grendel, the ONLY thing you need to change is the barrel. Everything else — bolt, magazines, gas system – is compatible with 6mm ARC.
▶ Official SAAMI Cartridge (not wildcat)
▶ Fits standard AR15-platform rifles
▶ Fits Short/Mini action bolt rifles
▶ Efficient short, fat case design
▶ 30-degree case shoulder
What Do I Need To Shoot the 6mm ARC?
Faxon and Ballistic Advantage are already producing barrels, with more manufacturers sure to follow. All the other required components are already on the market for 6.5 Grendel rifles. Aero Precision already offers complete 6mm ARC uppers.
If you’re converting a standard 5.56×45 mm (.223 Rem) AR15 upper to shoot 6mm ARC, you’ll need a 6mm barrel, a Type II 6.5 Grendel bolt carrier group, and new magazines. Some folks have suggested standard AR mags will work, but trust us, you want the magazines that have been designed for 6.5 Grendel. Most of the hardware you need is available at Brownells.
* While 6-6.5 Grendel shooters are known to run stout pressures, the new 6mm ARC cartridge has a relatively moderate Maximum Average Pressure (MAP) rating of 52,000 psi according to the official SAAMI specifications. For a variety of reasons, is wise to keep pressures in a semi-auto rifle moderate. Don’t chase the velocities you might get in a bolt-action gun.
Sierra Bullets has released load data for the 6.5 Grendel, a popular cartridge that works equally well in bolt guns and AR15-platform gas guns. Sierra published comprehensive 6.5 Grendel load data, covering 19 powders and eight (8) different bullets from 85 to 130 grains. NOTE: Hornady-brand brass (see below) was used for Sierra’s 6.5 Grendel tests, not the stronger Lapua 6.5 Grendel brass. Hand-loaders using Lapua 6.5 Grendel brass may need to adjust their loads. Also Winchester WSR primers were used. We imagine most precision hand-loaders will prefer CCI or Federal primers.
Sierra Bullets Tested for 6.5 Grendel Load Data
85gr HP (#1700)
100gr HP (#1710)
107gr HPBT (#1715)
In developing its 6.5 Grendel load data, Sierra tested a very wide selection of propellants, 19 in all. For the 85gr to 100gr varmint bullets, modern powders such as XMR 2230, Power Pro Varmint, and Ramshot TAC offered the best velocity in the 24″ test barrel. For the heavier 120gr to 130gr match bullets, Sierra tested a selection of powders. Highest velocities came with Power Pro Varmint and TAC. If you’re looking for best accuracy, consider the slower burn-rate powders such as IMR 8208 XBR and Varget — but you’ll sacrifice some speed. Overall, Sierra’s latest 6.5 Grendel load data is an excellent addition to the 6.5 Grendel knowledge base. Thanks Sierra!
Here are Sierra’s 6.5 Grendel Load Data Charts for Sierra’s 123gr HPBT, 130gr HPBT, and 130gr TMK. There are a five other tables for lighter-weight Sierra bullets.
History of the 6.5 Grendel Cartridge
The 6.5 Grendel originated as a 6mm PPC necked up to 6.5 mm. After Alexander Arms relinquished the “6.5 Grendel” Trademark, the 6.5 Grendel was standardized as an official SAAMI cartridge. It has become popular with target shooters and hunters alike because it is accurate, efficient, and offers modest recoil. Good for small to medium game, the 6.5 Grendel is available in lightweight hunting rifles, such as the Howa Mini Action Rifle. And the 6.5 Grendel is one of the most accurate cartridges suitable for modern AR-15 platform rifles.
On the Applied Ballistics Facebook Page, there was a fascinating series of posts showing traces of bullets at various speeds from Mach 0.86 to Mach 3.0. At the slowest speed, Mach 0.86, i.e. 962 FPS, there is turbulence behind the bullet, but no clear shockwave. At the highest velocity, Mach 3.0 (3375 FPS at sea level, 68° F), there is a dramatic double nose and tail wave formation.
To learn more, visit TheScienceofAccuracy.com. On that site you’ll find exclusive video content and you can subscribe to member’s only Podcasts. And you can purchase Applied Ballistics books on the Science of Accuracy webstore.
Mach 3.00 Bullet Flight Image
At Mach 3 (3355 FPS) this bullet now has a strong and well established shock wave forming at the tip, and at the base. Unlike the transition through Mach 1.0, nothing really interesting happens to the aerodynamics or shock waves meaning the aerodynamics and stability are: continuous, easy to predict, and model. As you go faster, the shockwaves make a shallower angle because the bullet is moving forward 3X faster than the shock wave is moving away from it. So the shock wave makes an angle that has a rise/run ratio of 1/3.
If a bullet flew within 10 feet of you traveling this fast, it would be about as loud as a 22 magnum. You’d certainly want hearing protection as the energy contained in a Mach 3 shock wave is high! How high…? Well, in 10 yards, this bullet slows from 3355 FPS to 3334 FPS in a time of 0.0090 seconds. The 55 ft-lb of kinetic energy lost during this 10 yards is due to aerodynamic drag on the bullet, which is comprised of wave, base, and skin friction drag components with the majority of the drag being due to shock wave formation. Expending 55 ft-lb of energy in 0.0090 seconds requires a power output of 6111 ft-lb/sec = 11.1 horsepower, most of which goes into creating the shock wave. Remember it’s a 3-D cone that travels great distance, and it gets its energy by stealing velocity from your bullet!
Mach 1.00 Bullet Flight Image
Many shots were fired to capture an image of the transonic shockwave structure at exactly Mach 1.00. With the bullet now moving at the speed of sound, the local airflow on some parts of the bullet exceeds Mach 1.0. Anytime something is moving thru the air faster than the air can get out of the way, you get a compression wave, aka “shock wave”. That’s what’s visible in this image — the areas where the air density changes rapidly (in the compression wave) are visible as near vertical lines and a detached bow wave out front. As the bullet progresses through transonic speed, this shockwave structure develops which has strong effects on the drag (wind sensitivity) and stability of the bullet.
The exact development of the shockwaves and the resulting effects are unique and sensitive to the bullet geometry, and become very difficult to predict through the transition from subsonic (incompressible flow without shock waves) to supersonic (compressible flow with shock waves). Each bullet geometry does this differently which is why it’s difficult to determine transonic stability criteria for bullets of different shapes.
Mach 0.86 Bullet Flight Image
Here’s a bullet at Mach 0.86 (86% the speed of sound, which is 962 FPS at 61° F). As you can see, this 0.86 Mach is not fast enough to make any discernable waves but you can see turbulence in the bullet wake (right side in photo). The beginning of small shock waves can be seen on the bullet tip, and at the bearing surface/boat tail juncture. For the most part, all of the airflow around this bullet is subsonic. You wouldn’t hear a supersonic ‘crack’ from this bullet flying past the observer.
The Risk of Hearing Loss
Quality foam earplugs offer great hearing protection at low cost. These Howard Leight 
