May 26th, 2017

NEW Federal Factory Ammo Loaded with Berger Bullets

Berger Bullets Gold Medal Berger Federal ammo ammunition 6.5 Grendel 6.5 Creedmoor PRS tactical .223 Rem .308 Win

This is a very interesting development. Federal will produce a line of Federal Gold Medal ammunition loaded with Berger Bullets match projectiles and GM Match primers. The new Gold Medal Berger ammo will initially be offered for: .223 Remington, 6.5 Grendel, 6.5 Creedmoor, and .308 Winchester. We expect this ammo to attract the attention of tactical and PRS shooters — Berger projectiles are currently favored by top PRS competitors. Depending on caliber, three different high-BC bullet types will be used: BT Target, Hybrid OTM, or Juggernaut OTM. These all feature a boat-tail design with a high BC for bullet weight. The 6.5 calibers will use Berger’s popular 130gr Berger Hybrid OTM bullet while the .308 Win uses the 185gr Juggernaut.

This new Gold Medal Berger ammo uses Federal Gold Medal match primers, Federal brass, and specially-formulated propellants. All the ammo is well under SAAMI-spec max OALs to function 100% in magazines. Federal says this ammo will “adhere to Federal Premium’s strictest specifications for accuracy, pressure and velocity”. This new GM Berger ammo line could be a match-worthy alternative for guys who don’t want to hand-load. We’re going to try some in 6.5 Creedmoor and see how it performs in terms of accuracy, ES/SD, ballistics, and temp stability. Should be an interesting test…

FEATURES of Gold Medal Berger Ammo:
• Most popular bullets at Precision Rifle Series events
• High ballistic coefficient
• Less wind drift and drop (than typical factory ammo)
• Excellent long-range accuracy
• Gold Medal match primer

Berger Bullets Gold Medal Berger Federal ammo ammunition 6.5 Grendel 6.5 Creedmoor PRS tactical .223 Rem .308 Win

Berger Bullets Gold Medal Berger Federal ammo ammunition 6.5 Grendel 6.5 Creedmoor PRS tactical .223 Rem .308 Win

Part No. / Description / MSRP
GM223BH73 / .223 Rem. 73-grain Berger BT Target / $32.95
GM65GDLBH130 / 6.5 Grendel 130-grain Berger Hybrid OTM / $34.95
GM65CRDBH130 / 6.5 Creedmoor 130-grain Berger Hybrid OTM / $34.95
GM308BH185 / .308 Win 185-grain Berger Juggernaut OTM / $34.95

Permalink Bullets, Brass, Ammo, New Product, Tactical No Comments »
April 7th, 2017

PRS Gas Gun Match — Winning Hardware and Match Strategies

PRS Gas Gun Match CORE Florida

Shooting Sports USA just released an excellent, in-depth article about the first-ever PRS Gas Gun Match. If you enjoy tactical-style shooting, or have an interest in modern semi-auto rifles, we strongly recommend you read this match report by SSUSA Editor John Parker. Offered in a magazine-style format, this SSUSA feature includes explanations of the rules and tactics for these matches, along with interviews with top competitors, including match winner SSG Tyler Payne of the USAMU.

CLICK HERE to Read PRS Gas Gun Match Report by Shooting Sports USA

Payne dominated the match, finishing 200 points ahead of the next competitor. Payne competed in Open Class shooting a JP Enterprises LRP-07 chambered in 6mm Creedmoor, running Berger 105gr 6mm Hybrids at 2975 fps. He used a Vortex Razor HD 4.5-27x56mm scope. With its 6X zoom ratio, this optic allowed SSG Payne to switch from a wide field of view to high magnification as the stage demanded. With targets out to 800 yards, having 27X on tap was useful.

There are three divisions in PRS Gas Gun Matches: Tactical Light (.223 Rem/5.56), Tactical Heavy (.308 Win), and Open. At this match, about 65% of shooters competed in Tac Light. Match Director Ryan Castle said: “The remaining 35% was split pretty evenly between Open and Tactical Heavy.”

Open Class Caliber Choices
“For Ammo in Open Class, 6mm and 6.5mm Creedmoor were popular — overall winner SSG Tyler Payne won using a rifle chambered in 6mm Creedmoor”. — John Parker, SSUSA

Gas guns to 800 yards, yep there are targets down there somewhere…
PRS Gas Gun Nightforce Optics CORE Florida AR15 AR
Jeff Cramblit Facebook photo

Gas Gun Match Loads — Short Range vs. Long Range
“The .223/5.56 [Tactical Light] guns had some lag time waiting on shot impacts. I believe the long-term solution may be to find a light and fast load for closer stages for near-instant reaction time and use a heavy load for the long shots to see splash and get the target to move a little more.” — Sean Murphy, Nightforce

Interview with Match Winner Tyler PaynePRS Gas Gun Match CORE Florida
SSG Tyler Payne told SSUSA: “This match has a lot of similarities to 3-Gun, which I’ve been shooting for 11 years now. With targets out to 800 yards, limited rounds and 30-second penalties, the match gave you the opportunity to go as fast as you wanted but really forced you to be accurate. Training for PRS has given me enough discipline to make my shots count and 3-Gun has taught me how to be efficient. Those two things helped me excel at this match. Having to slow down with a gas gun and make my shot count was very foreign to me. Usually at matches with a gas gun, you get as many shots as you want to take, so having to slow down was difficult.”

“If I had any pointers for someone wanting to try this type of match it would be to get out and confirm your data as far as you can. Don’t trust your ballistic Apps. Other than that, ask questions, watch the experienced shooters and have fun”.

Read more interviews HERE

PRS Gas Gun Series Rules

For the new PRS “Gasser” Competition, the PRS developed rules on gun types, scoring, match timing, penalties, safety and other key topics. CLICK HERE for Full PRS Gas Gun Series Rules.

Open Division: The Open Division rifles will not exceed a caliber of .30 or a velocity of 3,200 fps. With this and other divisions, Match Officials may request at any point during a match that a competitor fire their rifle through chronograph..

Tactical Light Division: Tactical Light Division rifles are restricted to 5.56 NATO/.223 Remington calibers only. Bullet weight cannot exceed 77 grains and muzzle velocity cannot exceed 3,000 fps.

Tactical Heavy Division: This class is restricted to .308 Win (7.62×51) gas guns. Most will be AR-10 platform rifles. Bullet weight cannot exceed 178 grains and muzzle velocity cannot exceed 2,800 fps.

Scoring and Penalties
The Gas Gun Series utilizes a time plus penalty-based scoring system for all match scoring. This means the score is the shooter’s total combined time on all stages plus any penalties accrued.

Penalties are as follows:
30 seconds for any rifle targets not engaged or neutralized.
15 seconds for any pistol targets not engaged or neutralized.
15 seconds for hitting a “No Shoot” target.
No more than 50% of the stages at a match can utilize an unlimited round count. At least 25% of the targets in Gas Gun Series match must be 2 MOA or smaller. Max distance is 800 yards.

Permalink Competition, Tactical No Comments »
November 2nd, 2016

NEW Sierra 6mm 110-Grain MatchKing with Claimed 0.617 G1 BC

Sierra 6mm 110gr matchking bullet BC 0.617

Sierra’s new 110gr 6mm MatchKing is so new you won’t even find it on Sierra’s website. But MidwayUSA has it listed as “coming soon”. This new bullet, optimized for a 1:7″-twist barrel, promises class-leading ballistics. The listed G1 Ballistic Coefficient (BC) is an impressive 0.617 (sorry, no G7 BC has been stated). That’s 12.8% higher than the 0.547 G1 BC Sierra claims for its older 107gr MatchKing. That’s a very significant improvement. We attribute the reduced drag of the new 110-grainer to an improved hybrid-ogive bullet shape along with much smaller meplats. Sierra has not yet confirmed that it is pointing the meplats of the new 6mm 110s at the factory, but we expect that may be the case. In this respect the 110-grainers could be like Sierra’s excellent 183gr 7mm MatchKings, which come with tight, pointed tips right out of the box.

Sierra 6mm 110gr matchking bullet BC 0.617

G1 vs. G7 and Listed BCs vs. Tested BCs — What You Need to Know

Manufacturer-listed G1 Ballistic Coefficients of 6mm Match Bullets
Sierra 110gr HPBT MK Sierra 107gr HPBT MK Berger 105gr Hybrid Tgt Hornady 108gr ELD
G1 BC = .617 @ 2500+ fps G1 BC = .547 @ 2500+ fps G1 BC = 0.536 G1 BC = 0.536

If you look at the table above you’ll see that Sierra’s claimed 0.617 G1 BC for the new 110gr MK is higher than the 0.536 Berger lists for its 105gr 6mm Hybrid and higher than the 0.536 Hornady lists for the new 108gr 6mm ELD Bullet. We do think Sierra’s 110-grainer will prove to have the highest BC of the bunch, based on recent comparison tests by Sierra.

Let’s explain… Sierra lists a 0.547 G1 BC for its 107-grain MatchKing. Sierra tells us that the the .547 listed BC is for the current lots of 107-grainers which are pointed by Sierra. Sierra’s Matt Reams states that the new 110-grainers definitely have less drag than the current Sierra 107gr MKs or Berger 105gr Hybrids: “We have shot the pointed 107s side by side (raced) in our 300-meter range next to the [Berger] 105s and our pointed 107s had a higher BC between those two lots. In the comparison we did, our lot of new pointed 107s had a slightly higher BC than the [Berger] 105s. The 110s are significantly higher than both.”

In the real world, Sierra’s new 110gr 6mm MatchKing may not have as big an edge over the competition as it seems from Sierra’s claimed 0.617 G1 BC. (The G7 numbers may be closer.) Nonetheless, we do expect that Sierra’s new 110-grainer will be very competitive, and may actually have best-in-class BC. And if the new 110gr SMKs come “tipped” from the factory that will be a very good thing.

Anybody currently shooting a heavy 6mm bullet in competition should look at the new 110gr MatchKing when it becomes available. It could prove to be a winner. NOTE However — Sierra recommends a true 1:7″-twist barrel to stabilize the new 110-grainers.

New Product Tip from Boyd Allen. We welcome reader submissions.
Permalink Bullets, Brass, Ammo, New Product, News 22 Comments »
September 8th, 2016

Berger Offers New 200.20X .30-Caliber Higher-BC Hybrid Bullet

Berger 200.20x Hybrid Match Target Bullet Bryan Litz U.S. Rifle Team F-TR

U.S. Rifle Team (F-TR) Selects New Berger 200.20X Bullet for 2017 World Championships
Berger Bullets has released new .30 caliber bullet that could be a game changer for the F-TR discipline — a bullet with exceptional accuracy and very high BC. Berger’s NEW 200.20X Hybrid Target Bullet is the result of extensive research and development in partnership with the U.S. Rifle Team (F-TR), world champion shooters, and accuracy enthusiasts within the long range shooting community.

The new 200.20X has a 0.640 G1/0.328 G7 BC compared to 0.616 G1/0.316 G7 for the older 200 grain .30 caliber Hybrid. That’s a significant reduction in drag. Recommended twist for the new bullet is 1:10″, same as with the earlier 200-grainer.

Berger Chief Ballistician and U.S. Rifle Team (F-TR) member Bryan Litz said, “This is the ideal bullet for F-TR and similar long-range disciplines. The 200.20X has a longer boat tail and nose, with shorter bearing surface which equates to less drag, a higher ballistic coefficient, and fewer points lost to the wind. The BC of the new 200.20X is 4% higher than the existing 200 grain Target Hybrid (G7 BC of 0.328 vs. 0.316). The shorter bearing surface also makes the 200.20X easy to load and shoot in standard chambers. New shooters won’t need special reamers or costly gunsmithing to make this bullet perform.” Bryan himself is switching to the new 200.20X: “After winning the 2015 National Mid-Range and Long Range F-TR Championships with the Berger 215 grain Target Hybrid, I’m switching to the 200.20X because it’s an even better option.”

Berger 200.20x Hybrid Match Target Bullet Bryan Litz U.S. Rifle Team F-TR

Bryan tells us that new 200-20X bullet requires a 1:10″ twist to achieve full stability and performance (BC) in most conditions, but you can shoot it out of a 1:11″ twist with a minor decrease in BC. For a stability analysis, enter this bullet in the Berger Stability Calculator with a weight of 200.2 grains, and a length of 1.508″ to get stability results for your particular rifle and atmospheric conditions.

After extensive field testing, this new 200.20X bullet has been adopted as the official .30 caliber match projectile for the U.S. Rifle Team (F-TR). The team verified that this new bullet offers very impressive performance — the higher BC equates to less wind drift, and this bullet has shown exceptional ability to “hold waterline”. Check out this 1000-yard group by Team member Dan Pohlabel, as shown on an electronic target monitor.

Berger 200.20x Hybrid Match Target Bullet Bryan Litz U.S. Rifle Team F-TR

To learn more about the new .30 caliber 200.20X Hybrid Target Bullet and its development, visit the Berger Bullets Blog for details. These 200.20X bullets are available right now through your favorite authorized Berger Bullets vendors.

About the U.S. Rifle Team (F-TR)
The two- time World Champion, U.S. Rifle Team (F-TR) is comprised of 30 shooters and coaches who have dedicated themselves to four years of training and preparation to represent the United States at the 2017 World Championships to be held in Canada. They compete all over the world at various ranges out to 1,000 yards.

Buy Bullets and Support U.S. Rifle Team (F-TR)
Eric Stecker, President of Berger Bullets said, “We are proud to be the Official Bullet of the U.S. Rifle Team (F-TR). To support our team, Berger Bullets will donate $1.00 for every box of 200.20X bullets sold towards U.S. Team expenses for the upcoming 2017 F-TR World Championships, which will be held at the Connaught Ranges in Ottawa, Canada.”

Permalink Bullets, Brass, Ammo, Competition, New Product 5 Comments »
August 26th, 2016

Whidden on Winning at Long Range: Part 2 — The Cartridge

John Whidden .243 Winchester Win National Championship Long Range Reloading Caliber Barnard Action Anschutz

John Whidden of Whidden Gunworks used the .243 Winchester cartridge to win the 2016 NRA Long Range Championship, his fourth LR title at Camp Perry. John selected the .243 Win because it offers excellent ballistics with manageable recoil. John says that, at least for a sling shooter, the .243 Win is hard to beat at long range. Yes, John says, you can get somewhat better ballistics with a .284 Win or .300 WSM, but you’ll pay a heavy price in increased recoil.

.243 Winchester — The Forgotten 6mm Cartridge for Long Range

by John Whidden, 2016 National Long Range Champion
My experience with the .243 cartridge for use as a Long Range High Power cartridge dates back about 10 years or so. After building a .300 WSM, I realized that the recoil was hurting the quality of my shots. The WSM shot great, but I couldn’t always execute good shots when shooting it. From here I built a 6.5-284, and it shot well. I also had a very accurate 6mmBR at the time, and my logic in going to the .243 Win was to get wind performance equal to the 6.5-284 with recoil similar to the 6mmBR. The experiment has worked out well indeed!

John Whidden .243 Winchester Win National Championship Long Range Reloading Caliber Barnard Action Anschutz

Championship-Winning Load: Berger Bullets, Lapua Brass, and Vihtavuori N160
For a load, currently I’m shooting Lapua brass, PMC primers (Russian, similar to Wolf), VihtaVuori N160 single-base powder, and Berger 105 grain Hybrid bullets. I switched to the Hybrid bullets fairly recently at the beginning of the 2015 season. Previously I shot the 105gr Berger hunting VLDs, and in testing I found that the Hybrids were just as accurate without having to seat the bullet into the lands. The velocity of this combination when shot through the excellent Bartlein 5R barrels (32” length) is around 3275 FPS.

For my match ammo, I seat the Berger 105 Hybrids well off the lands — my bullets are “jumping” from .035″-.060″. I only use one seating depth for ammunition for multiple guns (I know some benchrest shooters will stop reading right here!) and the bullets jump further in the worn barrels than in the fresh barrels. The bullets are pointed up in our Bullet Pointing Die System and are moly-coated. The moly (molybdenum disulfide) does extend the cleaning interval a little bit, probably 20% or so. The Lapua .243 Win brass is all neck-turned to .0125″ thickness.

Whidden’s .243 Win Ammo is Loaded on a Dillon
My loading process is different than many people expect. I load my ammo on a Dillon 650 progressive press using our own Whidden Gunworks dies. However powder charges are individually weighed with a stand-alone automated scale/trickler system from AutoTrickler.com (see below). Employing a high-end force restoration scale, this micro-processor controlled system offers single-kernel precision. The weighed charges are then dropped into the cases with a funnel mounted to the Dillon head.

John Whidden .243 Winchester Win National Championship Long Range Reloading Caliber Barnard Action Anschutz

John Whidden .243 Winchester Win National Championship Long Range Reloading Caliber Barnard Action Anschutz

The Lapua .243 Win brass is full-length sized every time, and I run one of our custom-sized expanders in my sizer die. The expander measures .243″ which yields the desired .001″ neck tension. In my experience, the best way to get consistent neck tension is to run an expander in the case neck at some point. When sizing the case neck by a minimal amount such as is the case here, I don’t find any negative points in using an expander in the sizer die.

In my experience, the keys to accurate long range ammo are top quality bullets and the most consistent neck tension you can produce. From these starting points, the use of quality components and accurate powder measurement will finish out the magic.

Great Ballistics with 6mm 105s at 3275 FPS
Running at an impressive 3275 FPS, Berger 6mm 105 grain Hybrids deliver ballistics that are hard to beat, according to John Whidden:

“My .243 Win shoots inside a 6.5-284 with 142-grainers. Nothing out there is really ahead of [the .243], in 1000-yard ballistics unless you get into the short magnums or .284s and those carry a very significant recoil penalty. In the past I did shoot the 6.5-284. I went to the .243 Win because it had similar ballistics but had much less recoil. It doesn’t beat me up as much and is not as fatiguing.

John Whidden .243 Winchester Win National Championship Long Range Reloading Caliber Barnard Action Anshutz

With the .243 Win, there’s no tensing-up, no anticipating. With the reduced recoil (compared to a 7mm or big .308), I can break and shoot very good quality shots. I find I just shoot better shots with the .243 than I ever did with the 6.5-284.”

John Whidden National Long Range Championship Camp Perry 2016 Wind Reading

Permalink - Articles, Competition, Reloading 9 Comments »
March 19th, 2016

6.5×47 Lapua — Accuracy to Spare for Tactical Applications

6.5x47 Lapua Tactical Rifle Ryan Pierce Brux Barrel H4350 Berger Hybrid

Last summer we published our comprehensive 6.5×47 Lapua Cartridge Guide, researched by the 6.5 Guys. In case you’ve been wondering what kind of accuracy is possible for a tactical-type rifle chambered for this mid-sized cartridge, check out this tack-driver built by gunsmith Ryan Pierce. That’s a mighty impressive 0.206″ five-shot group fired with Berger 140gr Hybrids using a Brux cut-rifled barrel. The powder was Hodgdon H4350, a very good choice for this cartridge.

6.5x47 Lapua Tactical Rifle Ryan Pierce Brux Barrel H4350 Berger Hybrid

Ryan reports: “Here is a 6.5×47 I built for a customer. It features a trued Rem 700 action, Brux 1:8″ Rem varmint-contour barrel, Mcmillan thumbhole stock, Surgeon bottom metal, and 3-port muzzle brake. The customer’s preferred load is the same that has worked in the last couple dozen 6.5x47s I’ve built: 41.1-41.3 grains of H4350 with 140 hybrids .050″ off the lands. This should run about 2810-2815 fps from a 26″ barrel. The 3.128″ refers to length of a loaded round from the base to ogive including the Hornady ogive comparator tool.”

6.5x47 Lapua Tactical Rifle Ryan Pierce Brux Barrel H4350 Berger Hybrid

Permalink Gunsmithing, Tactical 13 Comments »
August 31st, 2015

Can’t Find Varget or Reloder 15? Then Try IMR 4320

IMR 4320 Varget Powder Hodgdon reloading 6mm Dasher

IMR 4320 Varget Powder Hodgdon reloadingWhile Varget and Reloder 15 remain in short supply, you can often find IMR 4320 powder back in the shelves of local gun stores. IMR describes IMR 4320 as follows: “Short granulation, easy metering, and perfect for the 223 Remington, 22-250 Remington, 250 Savage and other medium burn rate cartridges.” This older-generation powder is more temp sensitive than the Hodgdon Extreme propellants, but in the right application, it looks to be a viable alternative for folks who can’t source Varget, Reloder 15, and even H4895.

IMR 4320 Shoots Well in the .308 Winchester
A while back, German Salazar wrote an excellent Riflemans Journal article, IMR 4320 — the Forgotten Powder. German developed IMR 4320 loads for his .308 Win Palma rifle and competed with IMR 4320-powered ammo at long range matches. German concluded that: “[IMR 4320] appears to be a very useful alternative to some of the harder-to-get powders. The load is working extremely well at 1000 yards. In the [2009] Arizona Palma State Championship, several high placing competitors were using the 4320 load. We got sub X-Ring elevation at 1000 yards from several rifles, and that’s all I’m looking for in a Palma load.”

IMR 4320 Works for Dasher Shooter
Forum member FalconPilot shoots a 6mm Dasher with Berger 105gr Hybrids. Looking for an alternative to Varget, he decided to give IMR 4320 a try. The results were good. FalconPilot reports: “I’ve been looking for other options (besides Reloder 15, which I love, but it’s really dirty). While at a gun shop in Ohio, I ran across 8 pounds of IMR 4320. I had never even heard of it, much less tried it. Getting ready for upcoming mid-range shoots, I loaded five rounds with IMR 4320 to the exact same specs as my winning Varget loads for the 6mm Dasher. This recipe was 32.7 grains of powder, Wolf SMR primer, Berger Hybrid 105 jumped fifty thousandths.” Falcon pilot tested his IMR 4320 load at 600 yards:

As you can see from the photo at the top of this article, FalconPilot had good results — a 1.5″ group at 600 yards. He reports: “This group was shoot during the middle of the day, mirage bad, scope set to 25X. It looks like IMR 4320 is a [very close] replacement for Varget… with a tad bit slower burn rate.” FalconPilot tell us the accuracy with IMR 4320 rivals the best he has gotten with Varget: “This gun has always shot under 2 inches [for 5 shots] at 600 yards, and most of time shoots 1.5 to 1.7 inches.”

For comparison purposes, here are Heat of Explosion and Burn Rate values from QuickLOAD for IMR 4320, and for the popular Reloder 15 and Varget powders. You can see that these powders have similar characteristics “by the numbers”:

Manufacturer Powder Brand Heat of Explosion Burning Rate Factor
IMR 4320 3890 0.5920
Alliant Reloder 15 3990 0.5200
Hodgdon (ADI) Varget 4050 0.6150

WARNING — When changing from one powder to another, always start with manufacturer’s stated load data. Start low and work up incrementally. Never assume that loads will be equivalent from one powder to another, even powders with similar burn rates.

What Other Forum Members Say:

I was using IMR 4320 in the mid 70s in my .222 Rem. Darned great powder and I never had a load that was not accurate from the .222 to .30-06 with that powder. — 5Spd

A fine powder overshadowed by the nouveau wave of “gotta have the newest — make me a better shot” powders. Try 4320 in a 22-250 — what a well-kept secret! IMR 4320 meters very well and is a flexible alternative to many of the hard-to-find powders so much in demand. — AreaOne

IMR 4320 was my “go to” powder in my .223 for many many years. This powder and Winchester 55gr soft point bulk bullets (the cheapest bullet I could buy at the time) accounted for thousands of prairie dogs, coyotes, and anything else that needed shooting. I still use IMR 4320 in some .223 loads and am very happy with it still. — pdog2062

I’ve been using it in a .308 Win for several years. I think it is very sensitive to temperature and always waited till the last minute to load my ammo with a close eye on the weekend forecast at the range. IMR 4320 Works pretty good for 155gr Palma and 168gr Hybrid [bullets] in my .308. — JayC

Permalink Bullets, Brass, Ammo, Reloading 8 Comments »
October 28th, 2014

Ogive No Jive — Litz Explains Tangent, Secant, and Hybrid Ogives

Secant and Tangent Ogive Bryan LitzIn discussions of ballistics, you’ll see references to “tangent” and “secant” 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 and secant designs, to help you understand the characteristics of both 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.”

hybrid bullet

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.

Berger Hybrid bullet, .308 30 CaliberHybrid 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.

Bryan Litz Explains Hybrid Design and Optimal Hybrid Seating Depths

Story sourced by Edlongrange.

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October 3rd, 2014

Hard-To-Find Products at Grafs.com Now

Grafs.com is now featuring some hard-to-find products that are very popular with our Forum members. These are items that sell out quickly, or may be back-ordered for months. Grab ‘em while you can.

grafs.com graf magnetospeed co-ax forster berger hybrid 7mm bullets

Berger 7mm 180gr Hybrids
Graf’s has the ultra-accurate, high-BC 7mm 180gr Berger Hybrid bullet. This 7mm Hybrid is probably the most popular projectile in use by top F-Class Open shooters. Yes, 7mm Hybrids are in stock now and ready to ship for $45.99 per 100.

Forster Co-Ax Reloading Press
Graf’s has the superb Forster Co-Ax Press in stock and ready to ship. This unique product is the “Cadillac of reloading presses”. Sizing and seating dies slide into universal jaws for quick die changes. The dies can also self-align in the press for reduced run-out on your loaded rounds. If you’ve been wanting a Co-Ax, grab one now as they can be hard to find between production runs.

Magnetospeed V3 Chronograph
Graf’s now sells the remarkable Third Generation Magnetospeed Chronograph. The original Magnetospeed was a “game-changer” in the shooting industry. This compact chrono attaches directly to your barrel so you don’t need to set up a tripod, and fiddle around aligning sky-screens or diffusers. You also don’t have to worry about putting a bullet hole (or two) in the middle of your chronograph. The latest “V3″ model Magnetospeed features an improved attachment system, an upgraded display/control module, plus software enhancements. And Magnetospeed now provides a rugged polymer case that holds the “bayonet” sensing unit, display module, and all other components. Price is $379.99

NOTE: All these prices include shipping with one $7.95 flat fee per order.

Permalink Bullets, Brass, Ammo, Hot Deals No Comments »
December 2nd, 2013

Slick F-TR with Adjustable Bag-Rider and Carbon-Metal Bipod

Forum member Jonathan L. (aka ‘Quest-QC’) was a member of the Canadian F-TR team at the F-Class World Championships in Raton, NM this fall. His handsome .308 Winchester rifle features some interesting hardware and a stunning African Padauk-wood stock stiffened with carbon fiber layers. We were impressed by the innovative, adjustable bag-rider assembly Jonathan fitted to the rear of his stock (scroll down for photo). With an Allen wrench, the vertical height and the slope (i.e. fore/aft angle) of the V-shaped bag-rider can be changed easily. This has many advantages. First, Jonathan can set his rifle to the most comfortable height (for his prone position) without using “lifters” under the rear bag. The system also gives him some gross elevation adjustment separate from the bipod. In addition, the angle adjustment allows the bag-rider to better match the geometry of the rear bag. Last but not least, by setting up the bag-rider with some drop (higher in front, lower in back), Jonathan can fine-tune his elevation (while aiming the gun) by simply sliding the rifle fore and aft.

F-TR F-t/r rifle starshooter .308 Win Winchester F-Class Berger Hybrids Adjustable stock bag rider Padauk African Wood Carbon Fiber Bipod

Jonathan says: “This year was my second year shooting at 1000 yards and I managed to find a spot on Team Canada for the FCWC at Raton. Here is the rifle that brought me there…”

F-TR F-t/r rifle starshooter .308 Win Winchester F-Class Berger Hybrids Adjustable stock bag rider Padauk African Wood Carbon Fiber Bipod

The rifle features a Kelbly Panda F-Class RB-LP action, 34″ Bartlein 1:11″-twist, Heavy Palma contour barrel. Fitted to the red-toned Padauk-wood stock is a 23.2 oz., StarShooter CF-SS light weight bipod with custom bench feet. On top is a March 8-80x56mm scope in Kelbly rings. Total weight of the rifle is 18 pounds, 1 oz., complete with the 24 oz. adjustable brass bag-rider at the back. The bag-rider block was modeled in 3D, then machined afterwards to use up the remaining weight available after all the other components. CLICK for StarShooter CF-SS Bipod Video.

African Padauk Wood is Very Stiff
Jonathan chose the red-toned African Padauk Wood because it is stiff for its weight: “The reason for choosing African Padauk is that the weight of the wood is the same as Maple but 45% more rigid.” The downside of Padauk, as Forum member Gstaylorg notes, is that it is a “very oily wood, which can make it somewhat difficult to finish with something like polyurethane. [Padauk] can generate a lot of bubbles and cause cracking problems around joints and/or seams.” Jonathan did note that he has observed a few bubbles in the auto clear coat on his stock. He plans to refinish the stock in the off-season.

F-TR F-t/r rifle starshooter .308 Win Winchester F-Class Berger Hybrids Adjustable stock bag rider Padauk African Wood Carbon Fiber Bipod

Gun Is Extremely Accurate with Berger 200gr Hybrids
Jonathan says this rig was very accurate, at least until his barrel gave up the ghost. He says he has put 15 successive shots in about 1/4 MOA: “I managed to make it twice (1/4 MOA for 15) by taking my time between shots. You don’t want to overheat this barrel. I needed to provide a very strong effort (mentally) to be able to achieve such precision as the rifle is way better than me.” Jonathan shoots Berger 200gr Hybrid bullets (in the lands) with Hodgdon Varget powder, and Federal 205M primers, loaded into neck-turned Lapua .308 Win brass. He has also had good luck with Vihtavuori N150 powder in the past.

F-TR F-t/r rifle starshooter .308 Win Winchester F-Class Berger Hybrids Adjustable stock bag rider Padauk African Wood Carbon Fiber Bipod

In compliance with F-Class rules, the adjustable bag-rider system would not be adjusted “on the fly” during record fire. The bag-rider’s vertical rise and fore/aft slope would be optimized before shooting, then locked in place. The bottom photo offers a good view of the V-shaped profile of the metal bag-rider. We have found that this kind of V-profile, closely matching the triangular profile of the rear ears, makes a rifle more secure in the rear bag and often allows the gun to track better.

F-TR F-t/r rifle starshooter .308 Win Winchester F-Class Berger Hybrids Adjustable stock bag rider Padauk African Wood Carbon Fiber Bipod

F-TR F-t/r rifle starshooter .308 Win Winchester F-Class Berger Hybrids Adjustable stock bag rider Padauk African Wood Carbon Fiber Bipod

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