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Introducing the 375 STALKER!


A prepper’s dream!

The 375 Stalker is what the 300 Blackout could have been, that was our ultimate goal. After working with Frank Sabatano at Maxim Firearms, we looked at what would fill the AR15 mag, feed, and still remain simple to make.

With the seemingly endless supply of damaged 308 cartridges we can now re-purpose them as the 375 Stalker instead of being tossed.

Parent case: .308/.270/.30-06/243
Brass Cut off Length: 1.560”


"In December of 2017, SATERN® Barrels/LIBERTY BARRELS® asked if I would be willing to do some research and development on a new caliber designed for the AR-15 platform. They provided a barrel, and a bolt, (same bolt as .450 Bushmaster and 458 SOCOM) and I purchased a SATERN® Big Bore Upper. 

Having 40 years of reloading experience, and experience with the AR platform, I agreed to do so, with my thanks for inclusion in a new venture.

Steve's idea was not to re-invent the wheel, but take lessons learned from some of the advances made from other calibers that had been introduced into the AR market, namely the .300 Whisper/Blackout.  The .375 Stalker brass was initially derived from once fired or neck split/damaged .308/.270/.30-06/243 brass.  Recycling the brass just like the .300 Whisper/Blackout is done.  My process was to cut the case to a length with a mini cut off saw, deburr the inside/outside of the neck, lubricate and run the case through the sizing die that he provided to me.  The case was then trimmed to length and the case mouth chamfered.  That is all you do, just like the .300 Whisper/Blackout. 

The day for testing came in February of 2018.  I compared data from several different cartridges and came up with a load that I thought would be safe enough to take to the range.  On range day, the rifle was placed in a vise, and the first round was fired.  The firearm functioned perfectly and had bolt lock back.  Examining the case showed no pressure signs, no indications of dangerous possibilities.  Two more rounds were fired, and the cases examined.  Those cases did show signs of pressure, and range day was over until adjustments could be made.

Approximately a week later, loads that had been reduced were taken to the range.  After a month testing stopped.   Conclusions are that the .375 Stalker shows extreme versatility, using bullets between 200 and 260 grains, with velocities anywhere from 1200 fps to 2200 fps, with no pressure issues.  The recoil is similar to a .243 with the heavier bullets, to a 30-06 with the 200 grain bullets at 2200 fps.  All loads cycled perfectly with 100% bolt lock back. The sound of the impact on the target berm was impressive.  This round is .300 Blackout on steroids!!

Being a hunter, I am looking at the application of this cartridge for use on hogs, moose, elk in mountain terrain, and any other big game that is hunted inside of 300 yards.  The foot pounds of energy is amazing, especially with the lighter bullets, with the energy equaling the velocity!!

In my conversations with Steve, I know that pressure barrels have been manufactured, and pressure testing is being conducted.  He also tells me that he has been in talks with Starline to produce factory .375 Stalker brass.  Hopefully gunpowder manufacturers will look at this cartridge, and develop load data for their own powders, giving more options to the reloader.  The ability to manufacture one’s own brass and use cast bullets will keep the cost of ammunition down. 

Remember, as always take any existing/provided reloading data, reduce it by 10% and work your way up to the existing load, watching for pressure signs. I personally have enjoyed the R & D of this round and am anxiously awaiting the first hog that ends up as the object of my sights."  Eric Milburn

 

  • Note from SATERN®: Results from formal pressure testing will be released when concluded.



Disclaimer:

All reloading and firing of reloaded ammunition are done at your own risk. The load data published by this website is intended discussion purposes only and for use by experienced reloaders only.  This information is to be used at the sole discretion of the user and the user assumes all risk.  Technical data and information contained herein are intended to provide information based upon the limited experience of individuals under specific conditions and circumstances. They do not detail the comprehensive training, procedures, techniques and safety precautions that are absolutely necessary to properly carry on similar activity. Always consult comprehensive reference manuals and bulletins for details of proper training requirements, procedures, techniques and safety precautions before attempting any similar activity. Be alert- publisher cannot be responsible for errors in published load data.

Do not attempt to reload until you have read and understand at least one printed reloading manual. Always wear safety glasses when reloading. Do not smoke while reloading. Keep primers and powder away from heat and open flames. Keep primers and powder where they cannot be accessed by children. Work up your loads following the standard procedures described in printed load manuals.

Reloading can be dangerous even when following published load data. The load data published by this website is intended for discussion purposes only.

SATERN® and LIBERTY® Barrels, Owners and Employees assume no responsibility for damages done to firearms while shooting reloaded ammunition.  We expressly disclaim any liability for the accuracy, use, or misinterpretation of the information provided here.

Although every effort has been made to provide accurate data, SATERN® and LIBERTY® Barrels assumes no responsibility for injuries, deaths, or damages due to typographical errors in the data, or any other mistake on the website or made by the individual reloaders.

To reiterate, all reloading and firing of reloaded ammunition is done at your own risk, SATERN® and LIBERTY® Barrels and its author(s) assume no liability for death, injuries, or damage due to the use of this, or any other load data.


Loading Data- Provided by Eric Milburn

 

375 Stalker 235 Gr. Speer Hot Cor Lil Gun

Weight

#1

#2

#3

#4

#5

Extreme

Standard

AVG FPS

Av. Ft. Lbs

15.5

1313

1270

1251

1240

1235

78

31.6

1261

831

16

1296

1291

1285

1272

1281

24

9.2

1285

861

16.5

1364

1365

1364

1347

1340

24

11.7

1356

959

17

1356

1383

1454

1434

ERR

98

45.14

1406

1033

17.5

ERR

1449

1480

1470

1485

36

15.93

1471

1129

18

1481

1444

1465

1545

1470

101

38.21

1481

1114

18.5

1530

1540

1527

1547

1598

71

28.84

1548

1251

19

1536

1543

1564

1586

1613

77

31.67

1568

1284

19.5

1596

1586

1687

1671

1652

101

45.14

1638

1401

20

1617

1636

1606

1633

1605

31

14.6

1619

1368

20.5

1628

1641

1648

1639

1635

22

7.39

1638

1400

21

ERR

1709

1703

1712

1713

10

4.5

1709

1524

21.5

1740

1737

1749

ERR

1723

26

10.8

1737

1580

22

1769

1788

1760

1778

1805

45

17.42

1780

1653

22.5

1851

1848

1818

1842

1851

36

14.4

1818

1771



200 GR Sierra Pro Hunter Lil Gun

Weight

#1

#2

#3

#4

#5

Extreme

Standard

AVG FPS

Av. Ft. Lbs

24.5

2021

2002

2033

2016

2055

53

19.9

2025

1821

25

2048

2068

2054

2044

2066

24

10.7

2056

1876

25.5

2110

2135

2160

2113

2137

50

20.4

2131

2016

26

2148

2138

2131

2172

2122

50

19.2

2142

2083

26.5

2187

2199

2169

 

 

30

15.1

2185

2120

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

260 GR Nosler Ballistic Tip Lil Gun

Weight

#1

#2

#3

#4

#5

Extreme

Standard

AVG FPS

Av. Ft. Lbs

17.5

1518

1527

1499

1525

1549

50

18

1523

1340

18

1573

1560

1550

ERR

ERR

23

11.5

1561

1406

18.5

1585

1569

1597

1597

1597

28

12.3

1589

1457

19

1593

1632

1625

 

 

39

20.8

1616

1508