LARGE BORE

PRECISION

WBY_338RPM_Main-232x1200

Rebated Precision Magnum

An ideal backcountry large game chambering, field testing of the 338 RPM has shown it to be a sledgehammer on North America’s biggest game, including elk, bear and moose.

Rebated Precision Magnum

An ideal backcountry large game chambering, field testing of the 338 RPM has shown it to be a sledgehammer on North America’s biggest game, including elk, bear and moose.

Tomorrow's Rifles Today

I am excited to announce the second cartridge in the Weatherby RPM family. It was a long time coming due to demand and supply chain delays, but I believe it will be worth the wait!

Upon the launch of the 6.5 WBY RPM in 2019, we began to dream of what could be next in the RPM family. Having successfully launched a 5 lb rifle in a 6.5 caliber magnum cartridge, I began to imagine what it would be like if we had a big bore option that could fit in the same Weatherby Mark V 6 lug action. Field testing for the 338 WBY RPM began back in 2020 when my son was able to take the first animal with Weatherby’s 16th cartridge introduction on a spring bear hunt. That following fall, Brenda and I both shot elk and moose ranging from 90 yards out to 550 yards and the cartridge performed tremendously.

When paired with the Peak 44 stock and the 3DHex recoil pad the recoil is surprisingly manageable with the 338 WBY RPM, even for a rifle of that weight. As I carried it around Africa this year, it was comforting to know that this well handling 5 lb rifle could confidently deliver the energy it needed to, even up against a tough Kudu at 490 yards. I’ve used bullets ranging in weight from 185 to 225 grains and have not been disappointed with the terminal performance I have seen out of multiple bullet designs. I must admit, this rifle and cartridge combination is going to be a go-to for me as I head to the backcountry in my home state of Wyoming.

I am truly honored to be able to carry on my grandfather’s legacy of cartridge development and rifle building. The pairing of this new cartridge with our latest rifles reminds me of one of his old slogans that said “Tomorrow’s Rifles Today.” I only wish he could be here to see the innovation and development that our amazing Sheridan-based team is able to accomplish.

Tomorrow's Rifles Today

I am excited to announce the second cartridge in the Weatherby RPM family. It was a long time coming due to demand and supply chain delays, but I believe it will be worth the wait!

Upon the launch of the 6.5 WBY RPM in 2019, we began to dream of what could be next in the RPM family. Having successfully launched a 5 lb rifle in a 6.5 caliber magnum cartridge, I began to imagine what it would be like if we had a big bore option that could fit in the same Weatherby Mark V 6 lug action. Field testing for the 338 WBY RPM began back in 2020 when my son was able to take the first animal with Weatherby’s 16th cartridge introduction on a spring bear hunt. That following fall, Brenda and I both shot elk and moose ranging from 90 yards out to 550 yards and the cartridge performed tremendously.

When paired with the Peak 44 stock and the 3DHex recoil pad the recoil is surprisingly manageable with the 338 WBY RPM, even for a rifle of that weight. As I carried it around Africa this year, it was comforting to know that this well handling 5 lb rifle could confidently deliver the energy it needed to, even up against a tough Kudu at 490 yards. I’ve used bullets ranging in weight from 185 to 225 grains and have not been disappointed with the terminal performance I have seen out of multiple bullet designs. I must admit, this rifle and cartridge combination is going to be a go-to for me as I head to the backcountry in my home state of Wyoming.

I am truly honored to be able to carry on my grandfather’s legacy of cartridge development and rifle building. The pairing of this new cartridge with our latest rifles reminds me of one of his old slogans that said “Tomorrow’s Rifles Today.” I only wish he could be here to see the innovation and development that our amazing Sheridan-based team is able to accomplish.

The RPM case was purpose built for the smaller Mark V six lug action to offer magnum performance in a lightweight package

Ballistics Information
Bullet Information Velocity (FPS) / Energy (Ft Lb) Trajectory (Path of Bullet)
Cartridge Name Bullet Weight Bullet Type Product Code B/C Muzzle 100 Yards 200 Yards 300 Yards 400 Yards 500 Yards 100 Yards 200 Yards 300 Yards 400 Yards 500 Yards
.338 WBY RPM 225 Nosler® Accubond® N338225ACB .55 2825 / 3987 2659 / 3531 2499 / 3119 2344 / 2745 2195 / 2406 2051 / 2101 1.7 0 -7.3 -20.9 -41.8
.338 WBY RPM 225 Hornady® Interlock® H338225IL .397 2800 / 3917 2572 / 3306 2356 / 2773 2150 / 2310 1955 / 1909 1771 / 1567 1.9 0 -8.2 -23.9 -48.7
.338 WBY RPM 185 Barnes® TTSX™ B338185TTSX .432 3100 / 3947 2876 / 3397 2663 / 2913 2460 / 2486 2266 / 2109 2080 / 1778 1.4 0 -6.2 -18.3 -37.1
.338 WBY RPM 225 Barnes® TTSX™ B338225TTSX .514 2800 / 3917 2623 / 3438 2453 / 3007 2290 / 2620 2132 / 2272 1981 / 1961 1.8 0 -7.6 -21.8 -43.6
Cartridge
Weight Grains
Bullet Type
Product Code
B/C
Muzzle
100 yards
200 yards
300 yards
400 yards
500 yards
Muzzle
100 yards
200 yards
300 yards
400 yards
500 yards
100 yards
200 yards
300 yards
400 yards
500 yards
338 WBY RPM Nosler Accubond
.338 WBY RPM
225
Nosler® Accubond®
N338225ACB
.55
Velocity
2825
2659
2499
2344
2195
2051
Energy
3987
3531
3119
2745
2406
2101
Bullet
1.7
0
-7.3
-20.9
-41.8
338 WBY RPM Hornady Interlock
.338 WBY RPM
225
Hornady® Interlock®
H338225IL
.397
Velocity
2800
2572
2356
2150
1955
1771
Energy
3917
3306
2773
2310
1909
1567
Bullet
1.9
0
-8.2
-23.9
-48.7
338 WBY RPM Barnes TTSX
.338 WBY RPM
185
Barnes® TTSX™
B338185TTSX
.432
Velocity
3100
2876
2663
2460
2266
2080
Energy
3947
3397
2913
2486
2109
1778
Bullet
1.4
0
-6.2
-18.3
-37.1
338 WBY RPM Barnes TTSX
.338 WBY RPM
225
Barnes® TTSX™
B338225TTSX
.514
Velocity
2800
2623
2453
2290
2132
1981
Energy
3917
3438
3007
2620
2272
1961
Bullet
1.8
0
-7.6
-21.8
-43.6

Velocity Comparison Chart

The Backcountry 2.0 Ti chambered in 338 WBY RPM features a short 18” barrel. With that reduction in barrel length comes some velocity changes compared to our standard 24″ barrels. Below is a chart comparing the 338 WBY RPM from our new 18″ barrel to our standard 24″ barrel.

Muzzle Velocity

Bullet 24″ Barrel 18″ Barrel
185gr Barnes TTSX 3100 2860
225gr Barnes TTSX 2800 2615
225gr Hornady Interlock 2825 2655
225gr Nosler Accubond 2800 2660

SAAMI Case Specs

View the 338 WBY RPM cartridge case specs direct from SAAMI.

See the 338 WBY RPM in Action

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Backcountry 2.0 Ti 18"

The Backcountry 2.0 Ti chambered in 338 WBY RPM features a short 18” barrel. It is the ultimate combination of balance, weight, and magnum performance, which is ideal for large game in the backcountry.

Backcountry 2.0 Carbon 20"

The Backcountry 2.0 Carbon Series chambered in 338 WBY RPM takes the ultra-lightweight Backcountry rifles and features a 20″ carbon fiber barrel at minimal weight increase. With the added advantages of stringing more shots with tighter groupings, the Backcountry 2.0 Carbon Series is everything a hardcore hunter could want while also offering advantages for the guy who wants to hit the range with less cooling time between shots.

338 WBY RPM

The 338 WBY RPM large bore precision in a 6 lug action. An ideal big game backcountry caliber.