January 04, 2011
By Zak Smith
Even U.S. shooters like this state-of-the-art long-range 6.5 cartridge. Here's why.
By Zak Smith
No 6.5mm caliber has ever been a big hit in the United States, but this is changing as long-range shooters seek more performance with less recoil.
The 6.5-284 Norma is a mainstay cartridge for long-range target shooters but requires a long action and suffers from short barrel life. Choices for a short-action 6.5mm cartridge are limited to the .260 Remington and wildcats such as the 6.5-08 Ackley.
Nammo Lapua Oy recently developed the new 6.5x47 Lapua cartridge specifically for long-range target shooting. In cooperation with Grunig & Elmiger, Lapua set out to develop a cartridge optimized for 300-meter CISM shooting, a sort of military olympic competition prevalent in Europe.
Somewhat similar to NRA Highpower shooting, 300-meter CISM has a set course of fire from defined shooting positions, using highly specialized target rifles.
Due to its excellent accuracy, good ballistics and low recoil, 6mm BR Norma currently dominates 300-meter CISM. When the 6.5x47 project officially started in 2005, two initial project goals were to improve ballistics by decreasing wind drift and to reduce barrel wear compared to the 6mm BR Norma, which will get only about 2,500 rounds at top accuracy before the barrel starts to show wear.
Stepping up from 6mm to 6.5mm provides a clear advantage in reduced wind drift, due to the increased ballistic coefficient values available in 6.5mm bullets. The increase in bore area also significantly extends barrel life over the 6mm BR Norma.
U.S. target shooters got wind of the new 6.5mm cartridge and suggested some changes, such as using small primer pockets for accuracy. The final list of design goals included following: excellent accuracy through quality and consistency, low wind drift, flat trajectory and low barrel wear.
The resulting 6.5x47 case has the same head and body diameter as the .308 Winchester and shares the same body taper. This allows use of the same magazines, bolts and actions as the ubiquitous .308.
Lapua set the maximum pressure for the cartridge at 63,090 psi, near the practical maximum for brass cases. In conjunction with a small primer pocket, the resulting case is very strong.
The 6.5x47 Lapua case is about 0.3 inch shorter than a .260 Remington case and has a sharper shoulder and a longer neck. With an overall loaded length of 2.700 to 2.800 inches, most bullets can be seated with their rear bearing surface above the case shoulder. It can be thought of as a shortened and "improved" .260 Remington case, with a small primer pocket.
Factory 6.5x47 Lapua loads shoot a 139-grain Lapua Scenar at 2,690 fps, the 123-grain Scenar at 2,790 fps or the 108-grain Scenar at 2,950 fps.
Midsized 6.5mm cartridges, which launch high-BC bullets at moderate velocities, provide wind deflection and drop values that equal or beat the .300 Winchester Magnum's standard 190-grain load with less than half the recoil and just over half as much powder burned. They blow the .308 Winchester out of the water. For long-range performance, it's a no-brainer.
To test Lapua's new cartridge, I had an Accuracy International Arctic Warfare model rebarreled from .308 Winchester to 6.5x47 Lapua.
G.A. Precision (gaprecision.net) chambered a 6.5mm barrel from Satern Custom Machining (satern machining.com) for the 6.5x47 Lapua cartridge and fit it to my Arctic Warfare. The cut-rifled Satern barrel was finished to about 25 inches and fluted to shave off a little weight.
I set out to determine how the cartridge would perform in both benchrest testing and long-range practical shooting in the field. With a pile of new Lapua brass and high-BC bullets from Lapua and Berger, I commenced load development.
The 6.5x47 Lapua case is only a few grains smaller than the .260 Remington case, so most .260 powders can be used. I focused on the 123-grain Lapua Scenar (.547 BC), 139-grain Lapua Scenar (.615 BC) and Berger 130-grain VLD (.595 BC).
When pushed with equivalent pressure, these bullets will provide almost identical wind performance to 1,000 yards. Powders such as Reloder 15, Hodgdon H4350, Vihta-Vuori N550 and Varget work well in the 6.5x47 Lapua. Best overall performance was achieved with RL15.
Accuracy with most combinations was excellent, with sub-quarter m.o.a. groups yielding from all three bullets with RL15 or N550 powder. Likewise, single-digit velocity standard deviation was common.
The 6.5x47 Lapua case is very strong, and the brass is excellent. I was able to meet and beat velocities achieved in my .260 with the 6.5x47 Lapua, but pressure was prematurely limited by primer cratering and an occasional pierced primer.
The fault was the rifle's. The Arctic Warfare is designed to reliably ignite 7.62 NATO ammunition in field conditions. Its firing pin protrusion and firing pin hole are not optimized for a high-pressure small-rifle primer.
Even with this limitation, my final load was the 123-grain Lapua Scenar at 2,930 fps, using RL15 and BR4 primers; it was about 110 fps faster than Lapua's factory load.
The 6.5x47 Lapua has proven itself a winner in both long-range bench-rest and in field-style practical and tactical matches. I took the converted Arctic Warfare to the Camp Guernsey Invitational Multi-Gun Match, which includes long-range rifle competition out to 700 yards.
An accurate rifle, rock-solid data and the light-recoiling 6.5x47 helped me dominate one of the two long-range stages, giving me the match points for an overall win over a field of 38 shooters.
Does the 6.5x47 Lapua offer anything over the regular .260 Remington? Ballistics are nearly identical, considering normal variation from gun to gun, and the 6.5x47 Lapua does it with just a few less grains of powder. To drive the same bullet at the same velocity in both calibers, the 6.5x47 Lapua load will have higher pressure; however, the Lapua brass seems to be able to handle that pressure just fine.
The most compelling reason to choose 6.5x47 Lapua is the excellent brass. Like the .260 Remington, the 6.5x47 Lapua provides long-range ballistics usually limited to the big magnums in a short-action package with low recoil. Because it shares the .308's head diameter and rough case dimensions, converting a .308 rifle to Lapua 6.5 is just a matter of replacing the barrel.
The 6.5x47 Lapua cartridge is a good solution for the shooter looking for a very accurate mid- to long-range rifle cartridge.