May 4th, 2019

Cartridge “Efficiency” — Factors to Consider from the USAMU

USAMU Handloading Guide Facebook cartridge efficiency

Efficient cartridges make excellent use of their available powder and case/bore capacity. They yield good ballistic performance with relatively little recoil and throat erosion.

USAMU Handloading Guide Facebook cartridge efficiency

Cartridge Efficiency: A Primer (pun intended!) by USAMU Staff

Each week, the U.S. Army Marksmanship Unit (USAMU) publishes a reloading article on its Facebook Page. In this week’s article, the USAMU discusses cartridge case efficiency and its benefits. While this is oriented primarily toward NRA High Power Rifle and Long Range (1000-yard) competition, these factors also apply to medium/big game hunters. Assuming one’s rifle and ammunition are accurate, key considerations include ballistic performance (i.e., resistance to wind effects, plus trajectory), recoil, and throat erosion/barrel life.

Efficient cartridges make excellent use of their available powder and case/bore capacity. They yield good ballistic performance with relatively little recoil and throat erosion. A classic example in the author’s experience involved a featherweight 7x57mm hunting/silhouette rifle. When loaded to modern-rifle pressures, just 43-44 grains of powder pushed a 139gr bullet at 2900 fps from its 22” barrel. Recoil in this light rifle was mild; it was very easy to shoot well, and its performance was superb.

An acquaintance chose a “do everything” 7mm Remington Magnum for use on medium game at short ranges. A larger, heavier rifle, it used ~65 grains of powder to achieve ~3200 fps with similar bullets — from its 26″ barrel. Recoil was higher, and he was sensitive to it, which hampered his shooting ability.

Similarly efficient calibers include the 6mm BR [Norma], and others. Today’s highly-efficient calibers, such as 6mm BR and a host of newer developments might use 28-30 grains of powder to launch a 105-107gr match bullet at speeds approaching the .243 Winchester. The .243 Win needs 40-45 grain charges at the same velocity.

Champion-level Long Range shooters need every ballistic edge feasible. They compete at a level where 1″ more or less drift in a wind change could make the difference between winning and losing. Shooters recognized this early on — the then-new .300 H&H Magnum quickly supplanted the .30-06 at the Wimbledon winner’s circle in the early days.

The .300 Winchester Magnum became popular, but its 190-220gr bullets had their work cut out for them once the 6.5-284 and its streamlined 140-142gr bullets arrived on the scene. The 6.5-284 gives superb accuracy and wind performance with about half the recoil of the big .30 magnums – albeit it is a known barrel-burner.

Currently, the 7mm Remington Short Action Ultra-Magnum (aka 7mm RSAUM), is giving stellar accuracy with cutting-edge, ~180 grain bullets, powder charges in the mid-50 grain range and velocities about 2800+ fps in long barrels. Beyond pure efficiency, the RSAUM’s modern, “short and fat” design helps ensure fine accuracy relative to older, longer cartridge designs of similar performance.

Recent design advances are yielding bullets with here-to-fore unheard-of ballistic efficiency; depending on the cartridge, they can make or break ones decision. Ballistic coefficients (“BC” — a numerical expression of a bullet’s ballistic efficiency) are soaring to new heights, and there are many exciting new avenues to explore.

The ideal choice [involves a careful] balancing act between bullet BCs, case capacity, velocity, barrel life, and recoil. But, as with new-car decisions, choosing can be half the fun!

Factors to Consider When Evaluating Cartridges
For competitive shooters… pristine accuracy and ballistic performance in the wind are critical. Flat trajectory benefits the hunter who may shoot at long, unknown distances (nowadays, range-finders help). However, this is of much less importance to competitors firing at known distances.

Recoil is an issue, particularly when one fires long strings during competition, and/or multiple strings in a day. Its effects are cumulative; cartridges with medium/heavy recoil can lead to shooter fatigue, disturbance of the shooting position and lower scores.

For hunters, who may only fire a few shots a year, recoil that does not induce flinching during sight-in, practice and hunting is a deciding factor. Depending on their game and ranges, etc., they may accept more recoil than the high-volume High Power or Long Range competitor.

Likewise, throat erosion/barrel life is important to competitive shooters, who fire thousands of rounds in practice and matches, vs. the medium/big game hunter. A cartridge that performs well ballistically with great accuracy, has long barrel life and low recoil is the competitive shooter’s ideal. For the hunter, other factors may weigh more heavily.

Cartridge Efficiency and Energy — Another Perspective
Lapua staffer Kevin Thomas explains that efficiency can be evaluated in terms of energy:

“Cartridge efficiency is pretty straight forward — energy in vs. energy out. Most modern single-based propellants run around 178-215 ft/lbs of energy per grain. These figures give the energy potential that you’re loading into the rifle. The resulting kinetic energy transferred to the bullet will give you the efficiency of the round. Most cases operate at around 20-25% efficiency. This is just another way to evaluate the potential of a given cartridge. There’s a big difference between this and simply looking at max velocities produced by various cartridges.”

Permalink Bullets, Brass, Ammo, Reloading 6 Comments »
October 19th, 2017

Paul Hill Wins European F-Open Championship with 7mm RSAUM

Paul Hill Bisley Europe European F-Class Championship

Shooter Profile by Des Parr, UK
We have a new European F-Open Champion: Paul Hill from the UK. If he looks familiar, it’s because Paul appeared here 12 months ago when he set a new F-Open record score of 100-17X at 900 yards at last year’s European Championships. There are some factors which make Paul’s victory all the more significant. First, he didn’t employ a top gunsmith to do his work — he’s a real working-class here who did it all himself. To keep costs down he taught himself to do all his own machining and bedding. Paul acquired a lathe, learned how to run it, and then carefully did all his own chambering and fitting. He then taught himself how to bed the rifle too. You have to admire a man who teaches himself how to build Championship-winning rifles.

Paul Hill Bisley Europe European F-Class Championship

Another unusual factor is Paul’s choice of components. Paul used the Lapua Scenar 180-grain bullet, the same bullet used to set his 2016 record. The 180gr Scenar is a fairly “old-fashioned” shape, but Paul points them using a “shooting shed” pointing tool. For seating, he uses his own home-made die with a Wilson top. Whatever the Lapuas may lack in BC, they more than compensate for in consistency, and that’s the key to success. As an aside, they compare very favourably in tests on the Juenke ICC machine, indicating that they’re very well made indeed.

7mm RSAUMPaul Hill Equipment List
Paul shot in the F-Open class firing the 7mm RSAUM cartridge, a short magnum. He ran a 30″ Krieger 1:9″-twist barrel mated to a Barnard Model P action bedded in a Joe West laminated stock. His pushed those Lapu8a Scenar with the relatively new Reload Swiss RS70 powder. Paul rates this RS70 propellant very highly. It may be unfamiliar to shooters in the USA, but RS70 is REACH compliant and is likely to become more popular when many other powders are forbidden from the EU next year. Paul is also a big fan of the Russian KVB-7 primer, a very mild and consistent primer — marketed under “Wolf” in the USA.

It is not just about having the right equipment though, it is also all about the application of skills and techniques and Paul was very keen to acknowledge his debt of thanks to Erik Cortina for his reloading techniques and Brian Litz for his writings on range mind set and diet. There is another, until now, secret factor that may have helped Paul. He is an Apiarist (bee-keeper) and he swears by the beneficial effects of his daily honey on toast. Who knows? Perhaps he’s on to something — nothing sells like success, so Paul’s honey sales may take off now just like his shooting career.

Here’s a good video showing F-Class Shooters at Bisley (FieldSports Channel 2015)

2016 Wasn’t So Bad Either
Paul Hill’s 2017 Championship win followed an impressive performance last year. At the 2016 European F-Class Championships at the Bisley Ranges, Paul set a record score at 900 yards: 100-17V! That’s 17 shots placed in a five-inch circle the size of a CD (compact disc) at over half a mile. [NOTE: At Bisley, the maximum score is FIVE points, not ten points. So the maximum score for 20 shots is 100. Also what Americans call an “X” is called a “V” at Bisley.]

Paul Hill Bisley Europe

Record Set with Slower Pair Firing Method
The style of shooting in Great Britain is pair-firing. Under this procedure, each of two competitors shoots alternately, taking turns from shot to shot. Each shooter has 45 seconds to take his shot. Allowing for the target pullers to do their jobs, this means that each shot can take up to one minute. As Paul was pair firing, he had to concentrate for up to 40 minutes to get all 20 shots off! You can imagine how many times the wind changed course in those 40 minutes –pick-ups, let-offs, changes of angle and direction. Paul had to counter each change and still managed to put 17 shots in that 5-inch circle!

Permalink Competition, News, Reloading No Comments »
August 29th, 2015

Game-Changer: Berger 7mm 195gr Bullet with 0.755 G1 BC

Berger 195 grain 195gr Elite Hunter .755 BC G1 G7 F-class

You’ve heard the rumors of a new ultra-high BC 7mm bullet from Berger. Well the rumors are true. Berger is now shipping test samples of its new 195-grain 7mm Elite Hunter Bullet, part # 28550. This bullet boasts jaw-droping 0.755 G1 and 0.387 G7 Ballistic Coefficients. Those are stunningly high numbers. Compare that to 0.674 G1 and 0.345 G7 BCs for the previous BC king amoung 7mm projectiles, Berger’s own 180 gr Match Hybrid Target.

We’re certain the “orange box” 195gr Elite Hunter will soon see use by F-Open competitors. This ultra-high BC projectile could be a “game-changer” in long-range shooting when used in cartridges such as the 7mm RSAUM, 7mm WSM and even bigger 7mm magnums. Recommended barrel twist rate is 1:8.3″, with a stated “minimum” twist of 1:9″.

We ran some numbers through the JBM Ballistics program*, comparing the new 195-grainer with Berger’s popular 180gr Hybrid. The results were eye-opening. The projected drop is significantly less. Most importantly, this new 195gr bullet moves a LOT less in the wind at 1000 yards. This should translate into higher scores for F-Class shooters — that wide ‘9’ shot may stay in the ’10’ ring. In fact, based on the JBM trajectory calculation, with a 10 mph 90° crosswind, the 195gr bullet will have over SEVEN INCHES less wind drift at 1000 yards than the 180-grainer (46.0″ vs. 53.1″). That’s a big deal, a very big deal…

Comparative Ballistics 195gr vs. 180gr Berger 7mm Bullets (10 mph 90° Crosswind)
Berger 7mm 195gr Elite Hunter 2950 fps Berger 7mm 180gr Hybrid Target 2950 fps
Drop at 800 yards: 135.5″
Windage at 800 yards: 28.0″
Drop at 800 yards: 140.9″
Windage at 800 yards: 32.2″
Drop at 1000 yards: 237.9″
Windage at 1000 yards: 46.0″
Drop at 1000 yards: 250.0″
Windage at 1000 yards: 53.1″
Drop at 1200 yards: 380.1″
Windage at 1200 yards: 69.6″
Drop at 1200 yards: 404.2″
Windage at 1200 yards: 81.2″

* Variables were set to 55.4° F, 1000′ elevation, standard Atmosphere at Altitude, 2950 fps muzzle velocity. You can use JBM Ballistics to compare at different MVs.

Berger 195 grain 195gr Elite Hunter .755 BC G1 G7 F-class

UPDATE from Berger

After we broke this story, Berger Bullets wanted to clarify some points. Berger explained:

“This bullet is in the testing phase and has not been officially launched. We sent this bullet out for some public testing to make sure that we had positive feedback before we moved forward with an official launch.

We want to see how it performs in multiple rifles and different chamberings.

This bullet was made for hunting purposes, we realize there are shooters who would like to take these out for target shooting, like F-Class. However, we are not certain how they will perform. If things are successful we would like to eventually launch a target version.”

The information on the label you have pictured on your article has been updated.

Twist Rates
Minimum: 1:9″
Optimum: 1:8.3″

Ballistic Coefficients
G7 BC: .387
G1 BC: .754

How to Get Berger’s 195gr Elite Hunter Bullets
These bullets are so new you won’t find them on the Berger Bullets website yet. As Berger explained above, these bullets are still in a final testing phase. Most of the early production runs have been sent out for testing purposes. If you have specific questions, you can send an email to Berger via this CONTACT PAGE. Otherwise you can phone Berger, Mon-Fri, at 714-441-7200. Please try the email option first.

The Extreme Store is listing the Berger 195gr 7mm Elite Hunter Bullet at $62.00 per 100 bullets, not including shipping.

Bullet boxes photo courtesy Ryan Pierce, PiercisionRifles.com
Permalink Bullets, Brass, Ammo, New Product 23 Comments »
November 25th, 2014

King Kenny and the Rise of the 7mm RSAUM

F-Open shooter Kenny Adams has enjoyed a spectacular 2013-14 season. Over the past 12 months “King Kenny” enjoyed a string of successes that established Adams as the man to beat in the ultra-competitive F-Open ranks. After finishing second at the 2013 F-Class Nationals, Kenny won the 2013 World Championship. He then won a series of regional matches heading into the 2014 National Championship. There he finished on the podium with a 3rd Place finish in the individual competition. He then earned gold as a member of the winning 4-man F-Open squad, Team Grizzly. We don’t think any other F-Open pilot has put together a stronger season.

Kenny attributes his success to great team-mates, great equipment, and great ammo. He’s a huge fan of Berger’s 7mm hybrid bullets: “The [Berger] 7mm 180 hybrids have made load testing much easier, and needless to say, raised my scores considerably!” Kenny also gave credit to his gunsmith: “I want to thank my gunsmith, Stick Starks from S&S — he got me going in this thing in the right direction four and a half years ago. Working with Stick has probably shaved a couple of YEARS off my learning curve.” Kenny’s world-championship rifle features a Panda F-Class action, Krieger barrel, and a Robertson F-Class stock. Kenny likes this combo so much he actually owns four complete red rifles with similar configurations. Check them out:

Kenny Adams

Kenny pushes those 180gr hybrids with the 7mm Remington SAUM (RSAUM) cartridge. A “new-generation” magnum, the RSAUM resembles a 6mm BR Norma on steroids. It has the same short, fat appearance, just scaled up — way up. This gives the 7mm RSAU the capacity to drive the big Berger 180-grainers at optimal velocities. The image below shows the older Berger 180gr VLD. Kenny shoots the newer 180gr Hybrid. They are both very, very accurate.

SAUM RSAUM 7mm

Kenny Adams F-Open

Banner Year for King Kenny
Pictured above is Kenny Adams holding his 1st Place Plaque from the 2013 F-Class World Championship. To the right, Ken (with fellow Team Grizzly members) is pictured at the 2014 F-Class Nationals accepting the Berger Trophy for the First Place F-Open 4-Man Team.

Below are Kenny Adams’s major shooting accomplishments from the past 12 months:

2013 – F-Class Nationals – 2nd Place F-Open.
2013 – F-Class World Championship – 1st Place F-Open.
2013 – Christmas Match in Florida – 1st Place F-Open.
2014 – Southwest Nationals – 1st Place F-Open 4-Man Team Grizzly (Set National record).
2014 – Orange Blossom Regional – 1st Place F-Open.
2014 – Sinclair East Coast Fullbore Nationals – 1st Place F-Open and set new Fullbore national record.
2014 – Mid West Palma – 1st Place F-Open 1200-yard match and set 1200-yard record.
2014 – F-Class Nationals – 3rd Place F-Open.
2014 – F-Class Nationals – 1st Place F-Open 4-Man Team Grizzly.

Kenny’s World-Beating 7mm RSAUM Load
For his 7mm RSAUMs Kenny loads Hodgdon H4350 powder and Federal 215m primers into Nosler or Norma RSAUM brass. In the RSAUM he runs Berger 180gr Hybrid bullets seated “just touching” the lands. Kenny is very precise with his charge weights. Using a Sartorius Magnetic Force Restoration scale, Kenny tries to hold his powder charges to within 1-2 kernels charge-weight consistency.

7mm RSAUM Kenny Adams

When you get it all correct, when every phase of the reloading process has been carried out perfectly, then you have rounds that can set records and win world titles. So what does championship-grade ammo look like? Take a look at the photo above. This is the 7mm RSAUM ammunition used by Kenny Adams at the 2014 Berger Southwest Nationals (SWN). Kenny is the 2013 F-Class World Champion.

Permalink Bullets, Brass, Ammo, Competition 7 Comments »
September 3rd, 2013

World F-Open Champion’s 7mm RSAUM Rifles by S&S Precision

Kenny Adams S&S PrecisionAmerican Kenny Adams is the new F-Open World Champion, winning the individual title last week at Raton, New Mexico. ‘King Kenny’ rose to the top through with skill, countless days of practice, and great determination. He put in the trigger time, including many long days at Raton. But when we cornered Kenny after his win at the Worlds he was quick to give credit to his gunsmith, Stick Starks of S&S Precision Rifles in Texas.

Kenny told us: “I want to thank my gunsmith, Stick Starks from S&S — he got me going in this thing in the right direction four and a half years ago. Working with Stick has probably shaved a couple of YEARS off my learning curve.” Kenny’s world-beating rifle features a Panda F-Class action placed in a Robertson F-Class stock. The Krieger barrel is chambered for the 7mm RSAUM.

Kenny Adams S&S Precision

Kenny Has Four Red F-Class Rifles All By S&S
What’s interesting is that Stick Starks made Kenny three other F-Class rigs, all with red Robertson stocks and Panda F-Class actions. So, counting the championship 7mm RSAUM, Kenny owns a fleet of four fire-engine-red F-Class rigs, all built by Stick at S&S. These three other red rifles were originally chambered in 6.5-284, 6mmBR, and 6.5×47, but Kenny switches barrels (and chamberings) to suit the venue and course of fire. In Raton, Kenny had two (2) of the red rifles chambered in 7mm RSAUM and two (2) chambered for the .284 Winchester. However, in the Individual World Championship he shot just one rifle, a 7mm RSAUM (shown below). He used the second 7mm RSAUM-chambered rifle in the F-Open Team Championship. This second RSAUM (used for team shooting) is the one pictured above, but his other RSAUM is identical in all respects. He did not shoot either .284 Win during the Worlds.

Kenny Adams S&S Precision F-Class Championship

Kenny’s World-Beating 7mm RSAUM Load
For his 7mm RSAUMs Kenny loads Hodgdon H4350 powder and Federal 215m primers into Nosler or Norma RSAUM brass. In the RSAUM he runs Berger 180gr Hybrid bullets seated “just touching” the lands. For his .284 Winchester-chambered rifles he loads necked-up Lapua 6.5-284 brass with 180gr Hybrids pushed by H4831sc powder and Federal 210m primers. Interestingly, he is very precise with his charge weights. Using a Sartorius Magnetic Force Restoration scale, Kenny tries to hold his powder charges to within 1-2 kernels charge-weight consistency.

While Kenny praised S&S for building great rifles, Stick is quick to say that Kenny deserves the credit: “He’s the man that pulled the trigger. He’s the man that beat the world. You can’t believe how dedicated Kenny is to his sport. He spends so much time shooting and practicing — true dedication. Kenny hung in there, never gave up, did the best a man can hope to do. Yeah you have to have good equipment, but you do have to have dedication in this sport. Buy the best equipment you can and the rest is up to you — learning how to read conditions. That’s all there is to it.”

S&S Can Build You a ‘Kenny Clone’ for $3800.00
By the way, if you want a gun just like Kenny’s, Stick told us: “I’ve got barrels, Panda F-Class actions, and I have one last Robertson F-Class stock left. Just one — these aren’t made any more you know. A complete build, with barrel of your choosing and Jewell trigger, will be about $3800.00.”

S&S Precision Rifles is a leading gunsmithing operation based in Argyle, Texas. Stick Starks and the crew at S&S build very accurate rifles, that also exhibit superb craftsmanship. While S&S built a championship-winning F-Open gun for Kenny, they can also built short-range benchrest rigs, as well as varmint and hunting rifles — all with hallmark S&S quality. S&S can handle every aspect of gunsmithing — chambering, bedding, even stock-painting.

In the video above, the folks at S&S put together some tack-drivers for their customers. There are some nice glimpses of bedding work, and barrel finishing. Watch carefully — at the 40-second mark you’ll see a sub-1/4″, 10-shot group that S&S co-owner “Stick” Starks shot at 200 yards with his 6.5×47 Lapua rifle. That’s serious accuracy. Half-way through the video, Stick offers advice for shooters looking for a super-accurate fun gun for club shoots: “If you want to shoot [at] 100 and 200 yards, I’d get me a 6BR or a 30 BR. It would be the most fun gun you ever had… and the barrel will probably last three or four thousand rounds.” If you want a gun to shoot at primarily 500-600 yards, Stick recommends the 6.5×47 Lapua chambering: “Run it with the Berger 130s and Hodgdon H4350 powder. That H4350 works great with the 130 Bergers.”

Permalink Competition, Gunsmithing 1 Comment »