338-378 Weatherby Magnum

(10 customer reviews)

$164.00 – $179.00

Released in 1998 the 338-378 has a larger case capacity and higher velocities than the 338 Lapua.

CARTRIDGE SPECS

Bullet Diameter: .338 (8.6mm)
Common Reference: 338 Caliber
Max Case Length: 2.913”
Production Start: 1998

BALLISTIC INFO

View Additional Info Below

SKU: 338378 Category: Tag:

Description

Ammunition Shipment Restrictions

Must be 18 or older to purchase rifle ammunition. Shipping not available to P.O. Boxes, International Addresses, AK, CA, HI, MA, CT, IL, NJ, NY nor DC residents. Residents of DE, KS, OH, and WA may have additional restrictions. All ammunition is shipped domestic ground and an adult signature is required. We do not accept returns on ammunition.

Designed to be faster than the popular 338 Lapua

Shooting a .338 caliber bullet, the 338-378 WBY was designed to be faster than the popular 338 Lapua. With a large case capacity the 338-378 is capable of long range shots while maintaining lethal energy.

Bullet Information

Barnes TTSX

Barnes® TTSX®

A 100-percent copper bullet with a polymer tip to boost ballistic coefficient to improve long-range ballistics and provide fast expansion. The four razor sharp cutting petals double the bullet diameter that wreak extensive internal damage and produce massive wound channels. The TTSX is extremely accurate and has great expansion.

  • Common Reference – 338 Caliber
  • Bullet Diameter – .338" (8.6mm)
  • Bullet Weight – 225 gr.
  • B/C (G1) – .514
  • Max Case Length – 2.913“

Barnes® TTSX®

A 100-percent copper bullet with a polymer tip to boost ballistic coefficient to improve long-range ballistics and provide fast expansion. The four razor sharp cutting petals double the bullet diameter that wreak extensive internal damage and produce massive wound channels. The TTSX is extremely accurate and has great expansion.

  • Common Reference – 338 Caliber
  • Bullet Diameter – .338" (8.6mm)
  • Bullet Weight – 225 gr.
  • B/C (G1) – .514
  • Max Case Length – 2.913“

VELOCITY DATA (FPS)

Bullet WeightMuzzle100 yds200 yds300 yds400 yds500 yds
225 gr.318029872802262524552290

ENERGY DATA (FT LBS)

Bullet WeightMuzzle100 yds200 yds300 yds400 yds500 yds
225 gr.505244573923344230102621

BULLET TRAJECTORY (INCHES)

Bullet Weight100 yds200 yds300 yds400 yds500 yds
225 gr.3.1“3.8“0.0“-8.8“-23.4“

Hammer Custom

Hammer Custom

Hammer Bullets™ are turned on a CNC lathe and use a unique solid copper blend that is designed for maximum terminal performance. Each bullet is weighed and micrometer measured as it is produced. The result is an incredibly consistent product with unparalleled quality control. The hollow point design, initiates expansion upon impact, shedding petals immediately, with the remainder of the bullet staying intact with a blunt front for optimal wound channel. All Hammer Custom Bullets are designed to optimize Weatherby’s flat shooting cartridges.

  • Common Reference – 338 Caliber
  • Bullet Diameter – .338" (8.6mm)
  • Bullet Weight – 262 gr.
  • B/C (G1) – .625
  • Max Case Length – 2.913“

LEARN MORE

Episode 41 - Hammer Bullets
On Our Mark Podcast

Episode 41 - Hammer Bullets

Take a deeper dive into Hammer Bullets with our On Our Mark podcast. We sit down with Bryan and Steve of Hammer Bullets to talk about the performance and what makes Hammer bullets different from similar projectiles.

LISTEN NOW

Hammer Custom

Hammer Bullets™ are turned on a CNC lathe and use a unique solid copper blend that is designed for maximum terminal performance. Each bullet is weighed and micrometer measured as it is produced. The result is an incredibly consistent product with unparalleled quality control. The hollow point design, initiates expansion upon impact, shedding petals immediately, with the remainder of the bullet staying intact with a blunt front for optimal wound channel. All Hammer Custom Bullets are designed to optimize Weatherby’s flat shooting cartridges.

  • Common Reference – 338 Caliber
  • Bullet Diameter – .338" (8.6mm)
  • Bullet Weight – 262 gr.
  • B/C (G1) – .625
  • Max Case Length – 2.913“

LEARN MORE

Episode 41 - Hammer Bullets
On Our Mark Podcast

Episode 41 - Hammer Bullets

Take a deeper dive into Hammer Bullets with our On Our Mark podcast. We sit down with Bryan and Steve of Hammer Bullets to talk about the performance and what makes Hammer bullets different from similar projectiles.

LISTEN NOW

VELOCITY DATA (FPS)

Bullet WeightMuzzle100 yds200 yds300 yds400 yds500 yds
262 gr.295027992653251223762243

ENERGY DATA (FT LBS)

Bullet WeightMuzzle100 yds200 yds300 yds400 yds500 yds
262 gr.506345584096367232832927

BULLET TRAJECTORY (INCHES)

Bullet Weight100 yds200 yds300 yds400 yds500 yds
262 gr.3.6“4.3““-9.8“-25.7“
Barnes® TTSX™Nosler® Partition®Hammer Bullett
Bullet Weight (grains)225250262
B/C (G1).514.473.625
Velocity (Ft/Sec)
Muzzle318030602950
@100 yds298728562799
@200 yds280226622653
@300 yds262524752512
@400 yds245522972376
@500 yds229021252243
Energy (FT LB)
Muzzle505251975063
@100 yds445745284558
@200 yds392339334096
@300 yds344234013672
@400 yds301029273283
@500 yds262125072927
Trajectory (Inches)
@100 yds3.1“3.5“3.6“
@200 yds3.8“4.2“4.3“
@300 yds0.0“0.0““
@400 yds-8.8“-9.8“-9.8“
@500 yds-23.4“-26.4“-25.7“

338-378 WBY MAG

Shooting a .338 caliber bullet, the 338-378 WBY was designed to be faster than the popular 338 Lapua. With a large case capacity the 338-378 is capable of long range shots while maintaining lethal energy.

TRAJECTORY

VELOCITY/ENERGY

338-378 WBY MAG

Shooting a .338 caliber bullet, the 338-378 WBY was designed to be faster than the popular 338 Lapua. With a large case capacity the 338-378 is capable of long range shots while maintaining lethal energy.

TRAJECTORY

VELOCITY/ENERGY

Shop Weatherby Unprimed Brass

  • Select options This product has multiple variants. The options may be chosen on the product page Quick View

    Once Fired Brass 20 count

    $20.00

    Once fired brass* available in 20 count boxes. * Box could contain mixed brands  Available calibers – .240 WBY; .257 WBY; .270 WBY;  .300 WBY ;  6.5-300 WBY; 6.5 WBY RPM; 7mm WBY

    Select options This product has multiple variants. The options may be chosen on the product page
  • Select options This product has multiple variants. The options may be chosen on the product page Quick View

    Unprimed Brass 20 Count

    $65.00 – $120.00

    20 rounds per box.

    Select options This product has multiple variants. The options may be chosen on the product page
  • Select options This product has multiple variants. The options may be chosen on the product page Quick View

    Unprimed Brass 50 Count

    $105.00 – $185.00

    50 rounds per box.

    Select options This product has multiple variants. The options may be chosen on the product page

Additional information

WeightN/A
DimensionsN/A
Bullet Options

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10 reviews for 338-378 Weatherby Magnum

  1. Swedish shooter –

    This is without a doubt the most killing caliber in the Wetherby line up, I’ve shot over 40+ Elk, 3 moose, 2 sheep, countless deer and Antalope with my Accumark and not one has taken 3 steps yet. With the lite bullets for deer and Antelope here in Wyoming, flat shooting Lazer accuracy. Ya it’s a big gun, but killing power trumps looking for wounded animals every day. 210 grain Scirocco and H1000 are a killing combo.

  2. Mike –

    Bought the Accumark Elite in 338-378 Weatherby about 8 months ago. I topped it with a NightForce SHV 5-20×56 and propped it with a Harris Bipod. I ordered 2 boxes of 225 Gr TTSX. Finally got to take it the range and get set up for deer and hog season. Bore sight had me within 2 inches at 30 yds. Lined it up and put the next 3 shots through the same hole. Stepped out to 100 and adjusted for 2 inches high. The next 6 shots were laser accurate. This rifle is a pleasure to shoot. Recoil isn’t bad at all. It’s more of a push and less of a punch. Smooth action, clean crisp trigger, and VERY accurate. The airblast quickly becomes the talk of everyone nearby! Don’t leave loose papers on the shooting table and certainly don’t shoot prone with the brake anywhere near the ground. Disclaimer… I love a rifle with solid kick. My instinct says that if you remove the brake, this one will absolutely rock you.

  3. Jim Eisenhart –

    Outstanding weapon! Bought mine in 2007 for a brown bear hunt on the Alaska Peninsula. First shot – Kill. 10’x10′. Acceleration is easily manageable with muzzle break and pad. Use it now for mule deer and elk in Colorado. I think you hear alot of other hunters doing there best to justify their decision not to buy the best…when secretly, they would rather have this rifle in this calibre! But I’m like my Canadian friends…just wish the ammo was more available! How do we make that happen?

  4. Ed Moeglein –

    Very accurate round thru my Mark V 225grn Zero @ 300 yds, 3 shots you an cover with a quarter!
    Wish the ammunition was available, I sure would do a lot more shooting.
    Saving my last 2 boxes for Hunting.

  5. T –

    people often ask why I need a caliber so big. They ask what I plan on shooting with it. My answer is simple. Whatever I want at whatever distance I want. Great round. A true talking point as well.

  6. The duke –

    I fell in love with this caliber after owning a true. 378. More power than necessary, but performance to match. Would give 6 stars if I could.

  7. jeff50jd –

    Very good ammo in my Accumark. The 250 grain Nosler Partition as accurate and make a awesome job on big game. I shoot 3 big moose’s and all 3 stop right there, same thing on black bear. Like the other comment I just wish the ammunition was more attainable here in Canada

  8. Westward –

    As a gunsmith, firearms dealer, and long range rifle builder of over 40 years, it is a pleasure to report our extensive field testing of the .338-.378 Wby Mag factory loads. Our rifle is an Unlimited Class 18 pound engineering masterpiece with 28 match barrel and PTG muzzle brake. We are consistently keeping this high performance shooter under 1/2 MOA throughout the full extreme ranges here in Western Washington. Job well done. And if you would like to try your skills at over 1/2 mile, this is THE caliber.

  9. huntin howie –

    Awesome up to 1500 yds. for bear, moose, elk, and more

  10. RHINOPENN –

    I have owned a mark V in this caliber for over 5yrs now, extremely happy with its performance here in northern BC Canada. It has anchored the biggest game we have here. From Bear,Moose,Elk. Out beyond 1100yrds. I just wish the ammunition was more attainable here in Canada.

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