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March 7th, 2018

Try Ballistol Lube for Case Sizing, STP for Neck Turning

If you’re using a body die or a full-length sizing die, try using Ballistol (in the aerosol can) as a lube. It works GREAT without the tacky or gooey residue left by most case lubes. It will also clean off carbon residues on the neck as you lube the case. Just spray a little on a cotton patch (or your fingertips) and wipe each case before you run it up into the die. If you are using a steel neck bushing, be sure to wipe the neck as well. You can usually do a half-dozen BR-sized cases before you need to re-apply Ballistol on the patch. Ballistol is non-toxic, bio-degradeable, and will not harm your skin. It is very slippery, but can easily be removed with a rag or paper towel. Try it–you may retire your One-Shot. Ballistol can also be used to protect wood stocks.

Note, for heavy case-forming or necking up case necks, we still recommend a thicker lubricant, such as Imperial Die Wax. But for normal case sizing, after your neck has been expanded, Ballistol will do the job, and you won’t need to tumble the brass afterwards. All you need is a very thin layer of Ballistol, and this easily wipes off with a paper towel.

For Neck-Turning, Try STP Blend or Assembly Lube
For lubing the neck-turning tool mandrel while turning case necks, many folks use a blend of STP® Oil Treatment and Mobil 1 lube. Chuckw2 reports: “Try STP and Mobile 1 Synthetic oil in a 50/50 mixture. Very slick, you will need to tumble your cases after turning.” STP is a very thick lubricant, that flows and clings almost like honey. Jason reports the STP blend comes off easily in an ultra-sound bath, using a bit of detergent. STP is also now available in a convenient 7-ounce tube, so you don’t have to buy a large bottle.

Assembly LubeAnother even cheaper option is assembly lubricant. For turning his case necks, RStreich uses assembly lube from an auto parts store. He notes: “The brand I have is reddish in color and kind of sticky like honey. It’s far better than the Imperial die wax I was using before.” There are a variety of types, both with and without moly additive, and you can select the viscosity you prefer if you sample a few brands. Be sure to clean out any lube residue from the inside of your necks when you have completed your neck-turning.

Permalink Reloading, Tech Tip 6 Comments »
March 4th, 2018

Valkyrie Velocity: Barrel Cut-Down Test with 60, 75, 90 grainers

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMK

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMKVelocity vs. barrel length — How much speed will I sacrifice with a shorter barrel? Hunters and competition shooters often ask that. Today we DO have solid answers to that question for many cartridge types thanks to Rifleshooter.com.

Rifleshooter.com has conducted a series of barrel cut-down tests for many popular chamberings: .223 Rem, 6mm Creedmoor, .243 Win, 6.5 Creedmoor, .308 Win, .300 Win Mag, .338 Lapua Magnum and more. And recently Rifleshooter.com added the new .224 Valkyrie cartridge to the list, cutting a 28″ Shilen barrel down to 16.5″ in one-inch increments. Rifleshooter.com measured the .224 Valkyrie’s velocities at each barrel length with four different types of factory ammo.

For its .224 Valkyrie test, RifleShooter.com sourced a Shilen Match Barrel and fitted it to a Rem 700 short action employing a one-piece PT&G bolt with the required .440″ (SPC-sized) bolt-face. The barreled action rides in a MDT LSS-XL Gen 2 Chassis.

READ .224 Valkyrie Barrel Cut-Down Test on Rifleshooter.com »

Bill, Rifleshooter.com’s Editor, explained his test procedure:

“I gathered four different types of factory Federal 224 Valkyrie ammunition, the 90gr Sierra MatchKing (SMK), 90gr Fusion soft point (SP) (referred to a Fusion MSR), 75gr Total Metal Jacket (TMJ) and 60gr Nosler Ballistic Tip Varmint (NBT). After a brief barrel break in and zero, I fired 5 rounds of each cartridge at each barrel length (except the 75 TMJ, I fired 4 rounds at each barrel length due to limited resources). I recorded the average muzzle velocity and standard deviation for each ammunition and barrel length combination and cut the barrel back 1 inch and repeated the process. I recorded barrel lengths from 28″ to 16.5″ (I try to save these barrels as finished 16″ tubes so they don’t go to waste).”

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMK

The Heavy Bullet 90gr Ammo Lost about 21 FPS per Inch
How did the test turn out? You’ll find all the results summarized in helpful tables with inch-by-inch velocity and SD numbers. For the two, 90gr ammo samples, results were similar. The 90gr SMK ammo started at 2782 fps (28″), finishing at 2541 fps (16.5″). That’s a loss of 241 fps, or 20.96 fps average per inch of length. The ammo loaded with 90gr Fusion SPs started at 2797 fps (28″) and ended at 2561 fps (16.5″), a drop of 236 fps. That’s 20.5 fps loss per inch. NOTE: Ambient temperature during the test was 45° F. You could expect the overall velocities to be a bit higher during hotter summer months.

See 90gr SMK Velocity/Length Test Chart | See 90gr Fusion SP Velocity/Length Test Chart

.224 Valkyrie Velocity Cut-Down Test

With a the smaller bullets, the effect was even more dramatic. As you’d expect they started out faster. The ammo with 60gr Nosler Ballistic Tips (NBT), a good choice for varminters, started at 3395 fps (28″), and declined to 3065 fps (16.5), a total velocity drop of 330 fps. Average velocity loss was 28.7 fps per inch of barrel length. Rifleshooter.com also tested Federal 75gr TMJ ammo.

About the .224 Valkyrie Cartridge

224 .224 Valkyrie barrel cut-down test velocity 90gr Sierra MatchKing Fusion SP TMK

The new .224 Valkyrie was introduced late last year as a Hot Rod cartridge that will work in AR15s. Designed to rival the .22 Nosler while still running well in ARs, the new .224 Valkyrie offers excellent long-range performance when loaded with modern, high-BC bullets. We expect some bolt-action PRS shooters might adopt the .224 Valkyrie. Why? Reduced recoil. With the 90gr SMK, the .224 Valkyrie offers ballistics similar to the 6.5 Creedmoor but with significantly less felt recoil. Check out this chart from Federal showing comparative recoil levels:

.224 Valkyrie Federal Rifleshooter.com cut-down barrel

.224 Valkyrie vs. .22-250 Remington
The Social Regressive explains: “There are two key reasons why the 224 Valkyrie is unique and desirable. First, it is specifically designed to fit the limitations of the AR-15 platform. It does so even when loaded with gigantic bullets, like the 90-grain SMK that Federal announced. .22-250 Rem is too long and too fat to work in the AR-15 platform; it needs an AR-10 bolt and magazine.”

Image from Social Regressive .224 Valkyrie Youtube Video.

The new .224 Valkyrie is basically a 6.8 SPC case necked down to .22-caliber. You can use your existing AR15 lower, but you will need a dedicated .224-Valkyrie upper, or at the minimum a new barrel, modified bolt with proper bolt face, and 6.8-compliant mags.

Permalink Bullets, Brass, Ammo, Gunsmithing, Tech Tip No Comments »
March 3rd, 2018

Tech Tip: Coping with Corrosive Ammo

Corrosive Ammo ammunition
Scary stuff — AK-74 after firing corrosive ammo and not being cleaned for a week.
Image courtesy
ADCOFirearms.com.

corrosive ammunition ammo BrownellsNo doubt you’ve heard the term “corrosive” used with respect to ammunition. But what exactly is “corrosive ammunition” (and how does it different from non-corrosive ammo)? What is the chemistry that leads to corrosion, and what cleaning procedures should you follow if you shoot corrosive ammunition? Brownells has come up with answers to these and other questions in a helpful TECH TIP video about corrosive ammo.

In this informative video, Brownells gun tech Steve Ostrem explains the primer-related chemistry that makes some ammo corrosive. The video then reviews suggested cleaning procedures you should follow after you have fired corrosive ammo through any firearms.

What Is “Corrosive” Ammunition?
What makes ammo “corrosive”? Generally speaking, primers are the problem. When corrosive ammunition is fired, the ignited primers leave a residue of corrosive salts. Typically these primers contain potassium chlorate, or sodium petrochlorate which, when burned, change into potassium chloride or sodium chloride. Sodium chloride is also known as common table salt.

Potassium chloride and sodium chloride are both very hygroscopic (i.e. they attract water). Because of that, these alkalis are rust generators. When exposed to the hydrogen and oxygen in the air (and moisture) potassium chloride and sodium chloride can form an acid that quickly causes metal rifle parts to rust and pit.

Given a choice, you may wish to avoid corrosive ammo altogether. However, for some types of fire-arms, particularly older military-style rifles, the most affordable ammunition may be corrosive. If you choose to use corrosive ammo, it is important to clean the gun thoroughly after use. After firing, you want to use an element that will neutralize the primer salts. Brownells suggests a water soak (see video above). Alternatively, Windex with ammonia can help neutralize the salts, but that doesn’t finish the job. After the salts have been neutralized and flushed away, basic anti-corrosion protectant (such as Eezox or other gun oil) should be applied to all metal parts.

This video ahows the effects of Corrosive Ammo after one month without cleaning:

To learn more about the proper procedures for cleaning rifles exposed to corrosive ammo, we suggest an article by Paul Markel on Ammoland.com. Markel, host of the popular Student of the Gun TV series, states that: “Windex (with ammonia) is the Corrosive Ammo shooter’s best friend. After you are done shooting your corrosive ammunition for the day, squirt the window cleaner liberally from the chamber down the barrel. Pull the bolt / bolt carrier / op rod if there is one and douse them as well. A couple of old cotton t-shirts will come in handy. A cotton barrel swab is a nice accessory but you can make do with patches. Some folks will rinse all of the ammonia and loosened corrosive salts off with hot water. Others prefer to wipe it all down and let the ammonia evaporate. Either way, once the corrosive salts have been tackled with the window cleaner, it is time for an all-purpose brush (old toothbrush) and some gun oil.” READ Full Article by Paul Markel.

Video Tip from EdLongrange. We welcome reader submissions.
Permalink - Videos, Tech Tip 7 Comments »
March 1st, 2018

Great Deal on 24-Gun Fire-Resistant Stack-On Safe

Walmart Stack-On Bargain Safe Combination Lock
This safe has a simple, combination dial lock. While slower to open, mechanical dial locks are more trouble-free than battery-powered keypad locking systems.

This is the best deal we’ve seen in a long time on a medium-sized, fire-resistant gun safe. If you don’t have a decent safe yet, this is a very good value. You get a 24-gun, fire-rated safe delivered to your doorstep for $459.00. No extra shipping charge. Hard to beat that. This safe usually costs over $675.00. It measures 55″ tall x 29.25″ wide x 20.25″ deep. Weight is 418 pounds. While that’s heavy enough to deter a “smash and grab”, we strongly recommend you bolt the safe in place.

Word to Wise about Rated Capacity
While this safe is rated for 24 long guns up to 54″ tall, realistically you can store 10-12 scoped rifles comfortably. You can also split the interior, using the provided shelves. Put rifles on one side and other valuables (cameras, jewelry, electronics, photo albums) on the other side.

Stack-On 24 Gun Fire Resistant Safe — Product Description
With a combination lock that is reinforced with a steel plate, this hunter green gun security safe ensures that your guns will stay securely locked up. The gun safe with combination lock has been tested and is verified to be fire-resistant for 30 minutes up to 1400 degrees Fahrenheit. The door stripping on the safe expands when exposed to high temperatures, sealing the contents inside from harm during a fire. The Stack-On 24 Gun Fire Resistant Safe has reinforced steel doors that are filled with fire retardant material, creating a protective firewall. This gun security safe has 2-way locking 1″ steel live action locking bolts and up to 5 locking points. Inside, the gun security safe is fully carpeted with 4 adjustable shelves to give you ample storage space. This durable Stack-On Gun Fire Resistant Safe is especially designed to resist deterioration and compression over time.

Delivery Information
This item is shipped via a freight trucking service. The company will call you to schedule a delivery appointment, so ensure someone is home at the scheduled delivery time. Please note that this item is available for curbside delivery only, and will not be moved into your home or garage. We recommend you have help available to move the item to its final location. Safe Weight is 418 pounds. That requires a pretty sturdy dolly.

Permalink Hot Deals, Tech Tip No Comments »
February 24th, 2018

Lyman Safety Recall for Black Powder Rifles and Pistols

Lyman recall muzzle loader black powder rifle pistol musket

Lyman Products is voluntarily recalling Lyman black powder rifles and pistols made in 2017. If you purchased one of these items, stop using it, check the serial number, and follow Lyman’s Recall Directions.

This recall includes black powder rifles and pistols regardless of caliber (including Deerstalker, Great Plains, Great Plains Hunter, Trade Rifle, Plains Pistol, Black Powder Kits, and replacement barrels; excluding Percussion Left Hand Great Plains and Left Hand Great Plains Hunter models) manufactured from March 1, 2017 to December 22, 2017. Barrels with the serial number in the range of A595960–A599026 are subject to this recall. If you bought one of the affected arms last year (2017), do not load and/or shoot it — you need to contact Lyman Products.

Check Your Serial Number

Owners of Lyman black powder rifles and/or pistols acquired at any time in 2017 or 2018 should immediately check the serial number:

Lyman recall muzzle loader black powder rifle pistol musket

What To Do Next — Instructions from Lyman

If you have a muzzle-loader that is involved in this recall, as confirmed by the serial number, do NOT use the gun. Instead, contact the Lyman Customer Service Department by emailing customerservice@lymanproducts.com or by calling 800-225-9626 Monday through Friday, 9 a.m. to 4:15 p.m. EST. You will be asked to provide your contact information, serial number, and either the part number or model to process the return. CLICK HERE for Lyman Recall INFO Page.

Upon receipt of the information provided to customer service, Lyman will send instructions and packaging to ship the product to Lyman for replacement at no cost to the customer. Lyman will provide a replacement barrel and tang with instructions or will replace the barrel and tang at Lyman and return the firearm. Please only return your rifle, pistol, or barrel and tang with the provided shipping tags and boxes. NOTE: Anyone outside the U.S.A. who is in possession of a black powder rifle or pistol within the recall range should contact your local distributor immediately.

Safety Recall Tip from EdLongrange. We welcome reader submissions.
Permalink News, Tech Tip No Comments »
February 23rd, 2018

Sinclair Int’l Offers 8-Part Series of Reloading Videos

free reloading videos sinclair international

Sinclair International has created a series of instructional videos illustrating the basics of metallic cartridge reloading. The 8-part series starts with reloading basics and provides step-by-step, how-to instructions that will help new reloaders get started. Detailed, animated illustrations show you what happens inside the chamber when shooting, and inside the dies during each step of reloading. The videos can be viewed on Sinclair Int’l’s YouTube page. Shown below is the first video in the series:

Each of the eight videos is hosted by Sinclair Int’l President Bill Gravatt. Bill doesn’t just show you “how”, he tells you “why”. The how-to segments cover case inspection, proper die set up, case sizing, primer installation, powder measuring, bullet seating, crimping, and even goes into the record keeping needed for the handloader. “We wanted to give shooters who haven’t reloaded a look at all the advantages of creating your own ammo and how easy it is to get started,” said Gravatt, “without telling them they had to have any certain brand or type of equipment to do the job.” The eight videos are:

Part 1 — Intro to Video Series
Part 2 — Intro to Reloading Safety
Part 3 — Metallic Cartridge Components
Part 4 — The Firing Sequence
Part 5 — Tools for Reloading
Part 6 — Loading Bottle-Neck Cartridges
Part 7 — Loading Straight Wall Cartridges
Part 8 — Reloading Series Conclusion

Reloading Tools
Shown below is Part 5 of the video series, covering the tools used for precision reloading.

Permalink - Videos, Reloading, Tech Tip No Comments »
February 20th, 2018

Generate “Cheat Sheet” — Printable Drop Chart for Your Rifle

Hornady Ballistics Calculator

Hornady Ballistics CalculatorNeed a simple, easy-to-use drop chart for your rifle? Something you can tape right to the buttstock? Then check out Hornady’s handy Online Ballistics Calculator. This user-friendly calculator will compute your drops accurately, and output a handy “Cheat Sheet” you can print and attach to your rifle. Simply input G1 or G7 BC values, muzzle velocity, bullet weight, zero range, and a few other variables. Click “Calculate” and you’ll see the full chart (shown below). Then if you click “View Cheatsheet”, you can generate the simpler, 4-line Drop Chart (shown above).

The online ballistics caculator is easy to use. You can select the basic version, or an advanced version with more data fields for environmental variables (altitude, temperature, air pressure, and humidity). You can also get wind drift numbers by inputing wind speed and wind angle.

Conveniently, on the trajectory output, come-ups are listed in both MOA and Mils — so this will work with either MOA clicks or Mil-based clicks. There are more sophisticated ballistics solvers available on the web (such as the outstanding Applied Ballistics Online Calculator), but the Hornady Calculator is very simple and easy to use. If you just want a basic drop chart, you may want to check this out.

Hornady Ballistics Calculator

Permalink Tactical, Tech Tip No Comments »
February 17th, 2018

Hexagonal Boron Nitride (HBN) for Bullet Coating

hexagonal Boron nitride bullets

For years, many shooters have coated bullets with Moly (molybdenum disulfide) or Danzac (tungsten disulfide or “WS2″). The idea was to reduce friction between bullets and barrel. In theory, this could lengthen barrel life and extend the number of rounds a shooter can fire between cleanings.

hexagonal Boron nitride bullets

Moly and WS2 both have their fans, but in recent years, many guys have switched to Hexagonal Boron Nitride (HBN), another dry lubricant. The advantage of HBN is that it won’t combine with moisture to create harmful acids. HBN is very slippery and it goes on clear, so it doesn’t leave a dirty mess on your hands or loading bench. Typically, HBN is applied via impact plating (tumbling), just as with Moly.

Good Source for Hexagonal Boron Nitride (HBN)
Paul Becigneul (aka PBike in our Forum) has been using HBN for many years with good results. He obtains his HBN from Momentive Performance Materials:

HBM boron nitride source momentive hexagonal bullet coatingMomentive Performance Materials
www.Momentive.com

Sales Contact: Robert Bell
Sales Email: robert.bell [at] momentive.com
Sales Phone: Robert Bell, (980) 231-5404

HBN Results — Both on Bullets and Barrel Bores
Many folks have asked, “Does Hexagonal Boron Nitride really work?” You’ll find answers to that and many other questions on gunsmith Stan Ware’s popular Bench-Talk.com Blog. There Paul Becigneul (aka Pbike) gives a detailed run-down on HBN use, comparing it to other friction-reducers. Paul also discusses the use of HBN in suspension to pre-coat the inside of barrels. Paul observes:

We coated our bullets … how we had been coating with WS2. Now our bullets have a slightly white sheen to them with kind of like a pearl coat. They are so slippery it takes a little practice to pick them up and not drop them on the trailer floor. What have we noticed down range? Nothing different from WS2 other than the black ring on your target around the bullet hole is now white or nonexistent. Our barrels clean just as clean as with WS2. Your hands aren’t black at the end of the day of shooting and that might be the most important part.

Interestingly, Becigneul decided to try a solution of HBN in alcohol, to pre-coat the inside of barrels. Paul had previously used a compound called Penephite to coat the inside of his barrels after cleaning. Paul explains:

If Penephite was used because it was slippery wouldn’t HBN be better? … We called Momentive again [our source for HBN], and talked about mixing HBN and 90% alcohol for a suspension agent to pre-lube our barrels. He though it sounded great but that the AC6111 Grade HBN would be better for this use. It would stand up in the alcohol suspension and cling to the barrel when passed through on a patch. We got some and mixed it in alcohol 90%. We use about one teaspoon in 16 ounces of alcohol.

We started using it this fall and what we have noticed is that now that first shot fired out of a clean and pre-lubed barrel can be trusted as the true impact point. We use tuners so now I got to the line, fire two shots judge my group for vertical, adjust the tuner as needed or not, and after tune has been achieved go to my record targets. This use has saved us in time at the bench and bullets in the backstop.

You really should read the whole article by Becigneul. He discusses the use of barrel lubes such as Penephite and “Lock-Ease” in some detail. Paul also provides links to HBN vendors and to the Material Safety Data Sheets (MSDS) for the various compounds he tested.

Permalink Reloading, Tech Tip 3 Comments »
February 16th, 2018

A Slice of (Barrel) Life — Inside Look at Barrel Erosion

So what does a “worn-out” barrel really look like? Tom Myers answered that question when he removed a 6.5-284 barrel and cut it down the middle to reveal throat wear. As you can see, there is a gap of about 5mm before the lands begin and you can see how the lands have thinned at the ends. (Note: even in a new barrel, there would be a section of freebore, so not all the 5mm gap represents wear.) There is actually just about 2mm of lands worn away. Tom notes: “Since I started out, I’ve chased the lands, moving out the seating depth .086″ (2.18 mm). I always seat to touch. My final touch dimension was 2.440″ with a Stoney Point .26 cal collet.”

Except for the 2mm of wear, the rifling otherwise looks decent, suggesting that setting back and rechambering this barrel could extend its useful life. Tom reports: “This was something I just thought I’d share if anyone was interested. I recently had to re-barrel my favorite prone rifle after its scores at 1,000 started to slip. I only ever shot Sierra 142gr MatchKings with VV N165 out of this barrel. It is a Hart and of course is button-rifled. I documented every round through the gun and got 2,300 over four years. Since I have the facilities, I used wire EDM (Electro Discharge Machining) to section the shot-out barrel in half. It was in amazingly good shape upon close inspection.”

Tom could have had this barrel set back, but he observed, “Lately I have had to increase powder charge to maintain 2,950 fps muzzle velocity. So to set it back would have only increased that problem. [And] I had a brand new 30″ Krieger all ready to screw on. I figured it was unlikely I’d get another full season on the old barrel, so I took it off.”

Permalink Gunsmithing, Tech Tip 6 Comments »
February 15th, 2018

Shooting on a Spinning Planet — The Coriolis Effect

Whittington Coriolis Effect
Photo by Dustin Ellermann at Whittington Center Range.

The Coriolis Effect comes into play with extreme long-range shots like this (2100 yards at Raton, NM). The rotation of the earth actually moves the target a small distance (in space) during the long duration of the bullet’s flight.

Coriolis Effect Bryan Litz Applied BallisticsWhen you’re out at the range, the Earth seems very stable. But it is actually a big sphere zooming through space while spinning around its axis, one complete turn every 24 hours. The rotation of the earth can create problems for extreme long-range shooters. During extended bullet flight times, the rotation of the planet causes an apparent deflection of the bullet path over very long distances. This is the ballistics manifestation of the Coriolis Effect.

Bryan Litz of Applied Ballistics discusses explains the Coriolis Effect in his Ballistics Books and Seminars. Bryan notes that Coriolis is “a very subtle effect. People like to make more of it than it is because it seems mysterious.” In most common shooting situations inside 1K, Coriolis is not important. At 1000 yards, the Effect represents less than one click (for most cartridge types). Even well past 1000 yards, in windy conditions, the Coriolis Effect may well be “lost in the noise”. But in very calm conditions, when shooting at extreme ranges, Bryan says you can benefit from adjusting your ballistics solution for Coriolis.

Bryan explains: “The Coriolis Effect… has to do with the spin of the earth. You are basically shooting from one point to another on a rotating sphere, in an inertial reference frame. The consequence of that is that, if the flight time of the bullet gets significantly long, the bullet can have an apparent drift from its intended target. The amount [of apparent drift] is very small — it depends on your latitude and azimuth of fire on the planet.”

Coriolis Effect Bryan Litz Applied Ballistics

Coriolis is a very subtle effect. With typical bullet BCs and velocities, you must get to at least 1000 yards before Coriolis amounts to even one click. Accordingly, Bryan advises: “Coriolis Effect is NOT something to think about on moving targets, it is NOT something to think about in high, uncertain wind environments because there are variables that are dominating your uncertainty picture, and the Coriolis will distract you more than the correction is worth.”

“Where you could think about Coriolis, and have it be a major impact on your hit percentage, is if you are shooting at extended range, at relatively small targets, in low-wind conditions. Where you know your muzzle velocity and BC very well, [and there are] pristine conditions, that’s where you’re going to see Coriolis creep in. You’ll receive more refinement and accuracy in your ballistics solutions if you account for Coriolis on those types of shots. But in most practical long-range shooting situations, Coriolis is NOT important. What IS important is to understand is when you should think about it and when you shouldn’t, i.e. when applying it will matter and when it won’t.”

The Coriolis Effect — General Physics
The Coriolis Effect is the apparent deflection of moving objects when the motion is described relative to a rotating reference frame. The Coriolis force acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame and is proportional to the object’s speed in the rotating frame.

A commonly encountered rotating reference frame is the Earth. The Coriolis effect is caused by the rotation of the Earth and the inertia of the mass experiencing the effect. Because the Earth completes only one rotation per day, the Coriolis force is quite small, and its effects generally become noticeable only for motions occurring over large distances and long periods of time. This force causes moving objects on the surface of the Earth to be deflected to the right (with respect to the direction of travel) in the Northern Hemisphere and to the left in the Southern Hemisphere. The horizontal deflection effect is greater near the poles and smallest at the equator, since the rate of change in the diameter of the circles of latitude when travelling north or south, increases the closer the object is to the poles. (Source: Wikipedia)

Permalink Shooting Skills, Tech Tip 3 Comments »