Forming 375 RAPTOR brass is accomplished with normal reloading tools, but you will want to make sure you have the following:
- 375 RAPTOR Full Length Resizing Die
- Imperial Sizing Wax
- 308 Winchester Shellholder for your reloading press
- A Power Case Trimmer set up to trim .375 caliber.
Brass Forming Process
- First, lubricate both the resizing die expander and the 308 Winchester brass you are starting with, in particular, you want to make sure the the inside of the neck is lubricated. My personal choice is Imperial Sizing Wax.
- Second, place the case in your standard reloading press that has been fitted with a 308 Winchester shell holder and the 375 RAPTOR Full Length Resizing Die. If you don’t want to expand the neck in one step, you can first use a .338 Caliber expander mandrel and finish the expansion and set the new shoulder angle with the 375 RAPTOR Full Length Resizing Die. In doing this operation using new Winchester commercial brass, the brass loss rate was 1%. In making 300 finished cased, 3 cases were scrapped with 1 case neck splitting and 2 cases necks collapsing.
- Finally, once expanded and the shoulder is set, all you need to do is trim the neck using a normal case trimmer to give you an overall case length of 1.865 inches. Depending on your parent 308 brass, this will require trimming .115″ to .125″.
- As an alternative process, it is possible to trim the parent 308 Winchester / 7.62 NATO brass using a common trimmer set-up for 308 Winchester. Following trimming, you then would resize using the 375 RAPTOR full length die and clean up the case mouth. This alternative process requires some experimenting to get the proper trim length based on the parent brass you choose.
Here is a video of the entire case forming process from start to finish:
and a photo of the process steps from 308 WINCHESTER to 375 RAPTOR:
Once you have completed initial forming and trimming of the 375 RAPTOR, you are now ready to wipe off the lubricant, prime your brass and proceed with loading ammo.
Note: If you plan to anneal the case necks, it is recommended that you do it after the first firing, before resizing.
The 375 RAPTOR is designed to shoot bullets ranging from 175 grains up to 350 grains to meet a wide range of applications from sporting to professional in both supersonic and subsonic use.
Here are just some of bullet options from Sierra, Nosler, Hornady, Speer and Lehigh:
- Lehigh 175 Grain Match – .248 G1 Ballistic Coefficient (Shown Above)
- Lehigh 175 Grain Controlled Fracturing – .237 G1 Ballistic Coefficient (Shown Above)
- Barnes 235 Grain TSX – .270 G1 Ballistic Coefficient
- Speer 235 Grain Hot-Cor – .317 G1 Ballistic Coefficient
- Lehigh 250 Grain Controlled Fracturing – .310 G1 Ballistic Coefficient (Shown Above)
- Sierra 250 Grain Game King – .371 G1 Ballistic Coefficient (Shown Above)
- Barnes 250 Grain TTSX – .438 G1 Ballistic Coefficient (Shown Above)
- Hornady 250 Grain GMX – .430 G1 Ballistic Coefficient
- Nosler 260 Grain Partition – .314 G1 Ballistic Coefficient (Shown Above)
- Nosler 260 Grain Accubond – .473 G1 Ballistic Coefficient (Shown Above)
- Nosler 260 Grain Solid – .254 G1 Ballistic Coefficient
- Speer 270 Grain Boat-Tail Soft Point – .429 G1 Ballistic Coefficient (Shown Above)
- Barnes 270 Grain LRX – .449 G1 Ballistic Coefficient
- Barnes 270 Grain TSX – .326 G1 Ballistic Coefficient
- Hornady 270 Grain Interlock – .380 G1 Ballistic Coefficient
- Speer 285 Grain Grand Slam – .354 G1 Ballistic Coefficient
- Lehigh 295 Grain Controlled Fracturing – .580 G1 Ballistic Coefficient (Shown Above)
- Barnes 300 Grain TSX – .357 G1 Ballistic Coefficient
- Sierra 300 Grain Game King – .470 G1 Ballistic Coefficient
- Nosler 300 Grain Partition – .398 G1 Ballistic Coefficient
- Nosler 300 Grain Accubond – .485 G1 Ballistic Coefficient
- Nosler 300 Grain Solid – .300 G1 Ballistic Coefficient
- Hornady 300 Grain DGX – .275 G1 Ballistic Coefficient
- Hornady 300 Grain DGS – .275 G1 Ballistic Coefficient
- Barnes 350 Grain TSX – .425 G1 Ballistic Coefficient
- Sierra 350 Grain Match King – .720 G1 Ballistic Coefficient (Shown Above)
Note: All bullets shown are loaded at or under the maximum magazine length of 2.800 inches taking full advantage of the operating capabilities of the AR-10, LR308, SR-25 and G2 platform.
Bullet Seating Depth Measurements – Cartridge Overall Length
- 175 Lehigh Match – 2.705″
- 175 Lehigh Controlled Fracture – 2.715″
- 235 Barnes TSX FB – 2.660″
- 250 Lehigh Controlled Fracture – 2.700″
- 250 Barnes TTSX – 2.730″
- 250 Sierra Game King – 2.690″
- 260 Nosler Partition – 2.580″
- 260 Nosler Accubond – 2.760″
- 260 Nosler Solid – 2.725″
- 270 Speer BTSP 2.790″
- 295 Lehigh Controlled Fracture 2.750″
- 300 Nosler Solid – 2.725″
- 300 Sierra Game King – 2.725″
- 350 Sierra MK – 2.800″
The .375 RAPTOR performs with a wide range of powders from Alliant, Hodgdon, IMR, Accurate, Western and Vihtavouri.
- Alliant Reloader 7
- Allian 1200R
- Alliant Reloader 10x
- Alliant Varmint
- Accurate 1680
- Accurate 2200
- Accurate 5744
- Accurate 2015
- Hodgdon Benchmark
- Hodgdon H322
- IMR XBR 8208
- Western Ramshot X-Terminator
- Vihtavouri N120
- Vihtavouri N130
- Vihtavouri N530
- Vihtavouri Tin-Star (Subsonic Applications)
This website will continually be updated with additional information, data, photos and videos.