7mm Shehane — Winning Wildcat for F-Open

After we posted Erik Cortina’s video featuring the trimming of 7mm Shehane cartridges with a Giraud Power Trimmer, many of our readers asked: “What’s a 7mm Shehane? How does it differ from a standard .284 Winchester?” To answer that question, we’re reprising a “cartridge profile” we ran a couple seasons back. This talks about the qualities of the 7mm Shehane, and includes a reamer print. The 7mm Shehane is an excellent “upgrade” to the .284 Win. The added capacity may not seem like much, but it allows some Shehane shooters to reach a higher, optimal velocity node.

7mm is the caliber to beat in F-Class Open Division (though many guys are looking hard at the big 30s.) With a standard .284 Winchester, or better yet, a .284 Improved, you can drive the high-BC Berger 180gr bullets to competitive velocities. A .284 Improved will shoot well inside a 6.5-284, and you’ll probably get significantly longer barrel life (at least 1800 rounds vs. as little as 1200 for the 6.5mm).

The straight .284 Win is a good cartridge, but in most barrels, it can’t push the 180s at 2900-2950 fps velocity levels*. A lot of barrels will top out at about 2850. That’s where the .284 Shehane comes into play. The .284 Shehane is a slightly modified wildcat that retains the same 35° shoulder as the parent case. However, by blowing the sidewalls out 0.010″, the .284 Shehane picks up about 3.3 grains of extra case capacity. That enhancement makes a BIG difference. The extra boiler room is enough to drive the 180s at 2900-2950 fps with H4831sc. With N560 or Reloder 17 you can go even faster.

Scotland’s Grant Taylor used the .284 Shehane to finish 3rd overall in the 2009 individual F-Class World Championships at Bisley, England. Grant reports: “I have a .284 Shehane and it’s very accurate with superb vertical spreads at 1000 yards. I have to thank Jim Hardy for putting me onto the caliber, it has awesome accuracy. I’m getting 2930-2950 fps with spreads in the 3-5 fps range. I use Hodgdon H4831sc powder, CCI BR2 primers, and pointed 180gr Bergers.”

Forum member Jim Hardy has shot the .284 with great success. He tells us: “In my humble opinion, the .284 Shehane is the best balanced long range round there is — bar none. I (perhaps_ have shot more of this chambering than anyone else, and it has proven better than I ever expected. Here is why:

You have to shoot a 30 Cal magnum with a 240gr bullet to equal the performance of most 7mm chamberings with the 180 Berger VLD. With the .284 Shehane, you have a .308 bolt face, medium action, and Lapua brass. You use less powder than the 7 mags, and have great accuracy and ballistics even while fire-forming. The .284 Shehane shoots inside the 6.5 AND the straight 284, the 300 WSM, and the 300 Win Mag with less recoil. The .284 Shehane offers twice the competitive barrel life of the 6.5-284, an easy 2950 fps with H4831 SC, [and it] can run 3000+ with N560 and Reloder 17, which is right there with the 7mm WSM. What is not to love about the 284 Shehane? It is a no-brainer for long range — F-Class or Prone or 1000-yard Benchrest.”

*Some exceptional barrels chambered in straight .284 Win can reach 2900 fps with the 180s. Ryan Pierce, who recently set a 450-24X Pending F-Open record, has a 32″ Brux barrel that is delivering 2900 fps with the straight .284. However, Ryan acknowledges that his velocities are not typical: “A lot of .284 Win barrels top out at around 2850 fps with the 180s.”

Similar Posts:

• .284 Shehane for Long-Range Competition
• .284 Shehane — Winning Wildcat for F-Open Competition
• Accurate Cartridges — The .284 Shehane, an Improved .284 Win
• Is the .284 Shehane Inherently Accurate? You Better Believe It
• Sunday GunDay: .284 Shehanes for F-Open Competition

Tags: .284 Win, .284 Winchester, Erik Cortina, H4831sc, Shehane