History
David Tubb's XC family (Superior Shooting Systems) shares one large case necked to each caliber, and the 30 XC is the .30 member of it. Take the 33 XC case, neck it down to .308, and the result is a big, high-capacity .30 in the same class as the .30-378 Weatherby, not an efficient mid-size target round.
This is a handloader's cartridge. Brass and components come through Superior Shooting Systems, and no factory loads it. Built around the heavy, high-BC .30 match bullets, it trades powder and barrel life for velocity and reach.
Lineage
It fires .308 inch (7.82mm) bullets and shares its head, body, and shoulder with the 33 XC and the larger 37 XC and 41 XC. Feeding comes from a magnum-length action on a large rifle magnum primer. Its peers are the other big .30 magnums: the .30-378 Weatherby, .300 Norma Magnum, .300 PRC, and .300 Remington Ultra Magnum.
Specifications
| Spec | Value |
|---|---|
| Case type | Rimless, bottlenecked |
| Bullet diameter | 7.82 mm (.308 in) |
| Neck diameter | 8.64 mm (.340 in) |
| Shoulder diameter | 14.25 mm (.561 in) |
| Base diameter | 14.87 mm (.585 in) |
| Rim diameter | 14.93 mm (.588 in) |
| Case length | 78.36 mm (3.085 in) |
| Family | XC line (David Tubb / Superior Shooting Systems) |
| Primer size | Large rifle magnum |
| Belted | No |
| Rifling twist | 1 in 9 in (recommended, for heavy .30 match) |
| Max pressure | No published SAAMI/C.I.P. figure |
| Recommended barrel | 32 in, 1:9 twist |
No standalone 30 XC print is published, so the cutaway is derived from the 33 XC case necked to .30 (the XC family shares a common case), keeping the head, body, shoulder, and datum and sizing the neck to .308. Treat the dimensions and drawing as the maker-derived reference, not a published standard.
Barrel Design
The twist I'd recommend is 1:9, fast enough to hold the heavy 200 to 230 grain high-BC .30 bullets stable through the transonic range at distance. Lighter bullets would be happy slower, but they are not what this cartridge is for.
A large, overbore .30 calls for a long barrel that lets the slow powders finish burning, so the baseline I'd recommend is 32 inches to collect the velocity the big case has to give. Barrel life is the trade: like the .30-378 it shares a class with, it erodes its throat, so treat the barrel as a consumable on a serious long-range rifle. The tables below come from representative handloads at that 32 inch barrel, and with no factory load to lean on, confirm your own on a chronograph before trusting any dial.
Handload Performance
Handload · 230 gr Berger Hybrid Target
| Range (yd) | Velocity (fps) | Elevation (mil) | Energy (ft-lb) | Windage (mil) |
|---|---|---|---|---|
| 0 | 3020 | -0.3 | 4657 | 0.3 |
| 100 | 2901 | 0.0 | 4296 | 0.1 |
| 200 | 2784 | -0.3 | 3957 | 0.3 |
| 300 | 2669 | -0.8 | 3637 | 0.4 |
| 400 | 2557 | -1.5 | 3338 | 0.5 |
| 500 | 2447 | -2.1 | 3059 | 0.7 |
| 600 | 2341 | -2.8 | 2798 | 0.8 |
| 700 | 2237 | -3.6 | 2555 | 1.0 |
| 800 | 2136 | -4.4 | 2330 | 1.2 |
| 900 | 2038 | -5.3 | 2120 | 1.4 |
| 1000 | 1942 | -6.3 | 1925 | 1.5 |
| 1100 | 1848 | -7.3 | 1743 | 1.7 |
| 1200 | 1756 | -8.3 | 1575 | 2.0 |
| 1300 | 1666 | -9.5 | 1418 | 2.2 |
| 1400 | 1579 | -10.7 | 1273 | 2.4 |
| 1500 | 1493 | -12.1 | 1138 | 2.7 |
| 1600 | 1409 | -13.5 | 1014 | 2.9 |
| 1700 | 1328 | -15.1 | 901 | 3.2 |
| 1800 | 1250 | -16.8 | 798 | 3.5 |
| 1900 | 1176 | -18.7 | 706 | 3.8 |
| 2000 | 1111 | -20.7 | 631 | 4.2 |
| 2100 | 1073 | -22.9 | 588 | 4.6 |
| 2200 | 1046 | -25.3 | 558 | 4.9 |
| 2300 | 1022 | -27.9 | 534 | 5.3 |
| 2400 | 1001 | -30.7 | 512 | 5.6 |
| 2500 | 981 | -33.6 | 492 | 6.0 |
| 2600 | 963 | -36.7 | 473 | 6.3 |
| 2700 | 945 | -40.0 | 456 | 6.7 |
| 2800 | 928 | -43.5 | 440 | 7.0 |
| 2900 | 912 | -47.1 | 425 | 7.4 |
| 3000 | 896 | -50.8 | 410 | 7.7 |
| 3100 | 881 | -54.8 | 396 | 8.1 |
| 3200 | 866 | -58.8 | 383 | 8.4 |
| 3300 | 852 | -63.1 | 370 | 8.8 |
| 3400 | 838 | -67.5 | 358 | 9.1 |
Muzzle velocity 3020 fps is the factory figure from a 32 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 200 to 230 grain .30 caliber match bullets, and a 32 inch barrel to burn the large powder charge. This is a big-case .30 built for reach, so the long barrel is essential.
Is the 30 XC a SAAMI cartridge?
No. The 30 XC is a proprietary cartridge from Superior Shooting Systems, handloaded from the maker's brass and components, with no published SAAMI or C.I.P. standard. There is no standalone 30 XC print, so the cutaway is derived from the 33 XC case necked to .30 per the maker's shared-case family.
How does it compare to the .30-378 Weatherby?
They land in similar territory: both are big, overbore .30s that drive heavy bullets fast and wear barrels quickly. The .30-378 is a belted Weatherby with factory ammunition; the 30 XC is a beltless, handloaded XC-family case. Choose by what brass and rifle you are building around.
What is it good for?
Long-range and extreme-long-range competition where reach and high retained velocity matter more than barrel life or recoil. It is not an efficient or high-volume cartridge; the smaller .30s do that job with far less powder and wear.