History
The CheyTac system arrived in the early 2000s to fill the gap between the .338 Lapua Magnum and the .50 BMG. The 375 is the .408 Cheyenne Tactical case necked down to .375 inch bullets. The .408 throws a heavier slug; the .375 trades frontal mass for a flatter trajectory and less recoil, and still drives very-high-BC lathe-turned solids past 2,000 yards supersonic.
C.I.P. standardized it rather than SAAMI, with the United States as country of origin and the alternative designation 9.5×77, and the dimensions here come from the C.I.P. TDCC datasheet. This is a specialist's cartridge, expensive to feed and built around solid bullets and long barrels. It is built for King of 2 Miles competition and long-range anti-materiel work, not for any general-purpose role.
Lineage
Necking the .408 to .375 inch (9.53mm) keeps the parent's large beltless, rimless head and steep shoulder. It feeds from a dedicated magnum-length ELR action and lights off with a large rifle magnum primer. The peers are the other big ELR rounds: the .375 EnABELR, .338 Lapua Magnum, .416 Barrett, and the .50 BMG it was designed to approach.
Specifications
| Spec | Value |
|---|---|
| Case type | Rimless, beltless, bottlenecked |
| Bullet diameter | 9.53 mm (.375 in) |
| Neck diameter | 10.31 mm (.406 in) |
| Shoulder diameter | 15.22 mm (.599 in) |
| Base diameter | 16.18 mm (.637 in) |
| Rim diameter | 16.25 mm (.640 in) |
| Case length | 76.91 mm (3.028 in) |
| Overall length | 113.40 mm (4.465 in) |
| Case capacity | ~150 gr H2O (nominal) |
| Primer size | Large rifle magnum |
| Belted | No |
| Rifling twist (C.I.P.) | 1 in 13 in (330 mm) |
| Max pressure | C.I.P. 4,400 bar (440 MPa, ~63,800 psi) |
| Recommended barrel | 38 in, 1:9 twist |
Dimensions are taken from the C.I.P. TDCC datasheet for the 375 CheyTac (cartridge maximum). C.I.P. headspaces on the shoulder and prints no datum circle, so the datum line on the cutaway is a derived mid-shoulder reference, not a published gauge dimension.
Barrel Design
A 375 CheyTac barrel is built for distance. The twist I'd recommend is 1:9, well faster than the C.I.P. standard 1:13, because the cartridge lives on the longest, heaviest .375 solids and the extra spin holds a healthy stability margin deep into the transonic past 2,000 yards. The factory rate stabilizes standard loads; the faster one is insurance for the heaviest projectiles an ELR shooter will actually reach for.
The case is enormous, so it needs a long barrel to burn the charge and a heavy one to be shootable. I'd put my baseline at 38 inches, an ELR-specific length that wrings out velocity and keeps the heavy solids supersonic well past a mile. The rifle is heavy, the muzzle blast is serious, and the ammunition is expensive, which is the deal you accept for a cartridge built to reach two miles. The tables below are computed at that 38 inch barrel; muzzle velocities are manufacturer figures and swing with barrel length and load, so confirm your own on a chronograph before trusting any dial.
Match Ammo Performance
Gunwerks · 377 gr Cutting Edge MTAC $15.20/rd
| Range (yd) | Velocity (fps) | Elevation (mil) | Energy (ft-lb) | Windage (mil) |
|---|---|---|---|---|
| 0 | 2900 | -0.3 | 7039 | 0.3 |
| 100 | 2800 | 0.0 | 6564 | 0.2 |
| 200 | 2702 | -0.3 | 6113 | 0.3 |
| 300 | 2606 | -0.9 | 5686 | 0.5 |
| 400 | 2512 | -1.6 | 5282 | 0.6 |
| 500 | 2420 | -2.2 | 4902 | 0.8 |
| 600 | 2330 | -3.0 | 4543 | 1.0 |
| 700 | 2241 | -3.8 | 4205 | 1.2 |
| 800 | 2155 | -4.6 | 3888 | 1.3 |
| 900 | 2071 | -5.5 | 3590 | 1.5 |
| 1000 | 1989 | -6.5 | 3310 | 1.7 |
| 1100 | 1908 | -7.4 | 3047 | 2.0 |
| 1200 | 1829 | -8.5 | 2799 | 2.2 |
| 1300 | 1751 | -9.6 | 2566 | 2.4 |
| 1400 | 1675 | -10.8 | 2347 | 2.7 |
| 1500 | 1600 | -12.1 | 2142 | 2.9 |
| 1600 | 1526 | -13.4 | 1950 | 3.2 |
| 1700 | 1455 | -14.9 | 1771 | 3.5 |
| 1800 | 1384 | -16.4 | 1604 | 3.8 |
| 1900 | 1316 | -18.0 | 1450 | 4.2 |
| 2000 | 1250 | -19.8 | 1307 | 4.5 |
| 2100 | 1186 | -21.7 | 1178 | 4.9 |
| 2200 | 1128 | -23.7 | 1064 | 5.3 |
| 2300 | 1088 | -25.9 | 990 | 5.7 |
| 2400 | 1061 | -28.3 | 943 | 6.1 |
| 2500 | 1040 | -30.8 | 905 | 6.6 |
| 2600 | 1021 | -33.5 | 872 | 7.0 |
| 2700 | 1003 | -36.4 | 842 | 7.5 |
| 2800 | 986 | -39.4 | 814 | 7.9 |
| 2900 | 970 | -42.5 | 788 | 8.3 |
| 3000 | 955 | -45.8 | 764 | 8.8 |
| 3100 | 941 | -49.2 | 741 | 9.2 |
| 3200 | 927 | -52.7 | 719 | 9.7 |
| 3300 | 913 | -56.4 | 698 | 10.1 |
| 3400 | 900 | -60.3 | 678 | 10.6 |
Muzzle velocity 2900 fps is the factory figure from a 38 in test barrel. Expect your own barrel to read a little differently. Velocity is color coded green supersonic, yellow transonic, red subsonic; treat transonic and subsonic rows as approximate.
Trajectory
FAQ
What barrel length and twist should I run?
A 1:9 twist for the heavy .375 solids the cartridge is built around (faster than the C.I.P. standard 1:13, for stability margin at extreme range) and a long 38 inch barrel to collect velocity and hold those bullets supersonic past a mile. This is a dedicated ELR build.
Is the 375 CheyTac a SAAMI cartridge?
No. The 375 CheyTac is standardized by C.I.P., with the United States as its country of origin and the alternative designation 9.5×77. The dimensions on this page come from the C.I.P. TDCC datasheet. Because C.I.P. headspaces on the shoulder, there is no published datum circle; the datum shown on the cutaway is a derived mid-shoulder reference.
How does it compare to the .408 CheyTac and .50 BMG?
The 375 CheyTac shoots flatter than its .408 parent and far flatter than the .50 BMG, with less recoil than either, by trading bullet mass for velocity and a high-BC .375 solid. The .50 BMG still carries more energy at any range; the CheyTac's advantage is precision and trajectory, which is why it dominates extreme-long-range target competition rather than the heavy anti-materiel role.
What is it good for?
Extreme long range (King of 2 Miles and similar competition) and long-range anti-materiel work. It holds supersonic velocity and meaningful energy past 2,000 yards, which is the whole reason to accept its size, recoil, and cost. For anything inside a mile, a .338 or .375 on a smaller case does the job with far less expense.