7mm-6.5×47 Lapua — New Mid-Sized Wildcat Cartridge Tested
Jason Baney was one of the “founding fathers” of this website when we started out as 6mmBR.com a decade ago. Jason’s latest project involves an interesting wildcat, a mid-sized 7mm cartridge based on the 6.5×47 Lapua case. In this report, Jason (who now works at Eurooptic.com) talks about the 7×47 wildcat and his initial velocity (and feasibility) tests. To determine the 7×47’s velocity potential, Jason did a multi-stage test, cutting a barrel in two-inch increments. This process is illustrated in a video, embedded below. You may be surprised that the little 7×47 cartridge could drive a 180gr Berger Hybrid at 2770+ FPS with a 32″ barrel and Reloder 17. Max Velocity with H4350 (and 32″ barrel) was roughly 70 FPS slower. With a 24″ barrel length, the 7×47 was still able to propel the 180gr Hybrids over 2600 FPS with H4350. That’s impressive performance for a mid-sized cartridge pushing a very big bullet.
7×47 Lapua Part 1: Velocity Study
By Jason Baney, Eurooptic.com
The biggest enemy in long-range shooting is wind. This also happens to be the hardest to gauge and predict. The only way mere mortals can attempt to defeat the wind demons is to shoot a cartridge with the most ballistic efficiency, yet maintain a user-friendly combination of recoil and component consumption as well as performance on target.
The 7mm bullets tend to yield the best compromise of all of these aspects. Their BC-to-weight ratio is outstanding and 7mm bullets provide sufficient impact energy for most situations. In addition to that, the recoil of 7mm bullets can be more manageable than heavier/larger .30 and .338 caliber projectiles.
In cartridge design, of course you want the best case possible. Having used the 6.5×47 Lapua since its release in 2006, I felt this cartridge was the perfect choice to start with as I wanted a true short-action non-magnum round that gave the least possible wind drift to 1000 yards. The 6.5×47 parent case also allowed seating of the heavy 180gr class bullets completely out in the neck yet it maintained an overall length that would actually work in a factory Remington short action magazine.
