August 26th 2023Same Lapua 6BR Ammo in Four Barrels — Surprising VelocityResultsPut the exact same load into a variety (with the same chambering and length) of barrels and you will see a wide variation in muzzle velocity. It’s not uncommon to see a difference of up to 100 fps between barrels. This was demonstrated with a comparison of Lapua factory ammunition.In Southern California, we chronographed Lapua 6mmBR factory ammunition in three different 8 twist barrels of similar size. The results were amazing. Lapua specifies this ammo as 2790 fps based on Lapua testing with their own 26? We observed a speed variance of 67 fps based on tests with three aftermarket barrels. Based on three aftermarket barrels, we observed a speed variation of 67 fps.
Brand ‘S” and Brand “PN” were pre-fitted barrels that were fired on Savage actions. Brand ‘K” was fitted to a customized action. All test barrels had been throated to accept the 100-108 grain Bullets, but there may have still been slight variations in barrel freebore. Brand PN was the fastest barrel, averaging 2824 fps. This is 67 fps more than the slowest barrel. The slightly longer length (27?) can be attributed for approximately 10 fps. vs. 26? Click Here for Results of 6mmBR Barrel Length Velocity Test. Important: Results are barrel-specific, not brand-specificThese tests show that the same load can perform very different in different barrels. We don’t publish the barrel makers’ names because it’s wrong to assume ‘Brand X is always going faster than ‘Brand Y,’ based on results from a single test barrel. Two identical barrels from the SAME maker can have a difference in velocity of up to 100 fps. You can have two 8? You can have two barrels with the same land groove configuration and contour from the same manufacturer. One barrel may be faster than the other.
We often hear guys say, “I don’t get it… How can you guys get 2840 fps when I only get 2900 with your 6BRs?” It could be that your barrel is slower than the average. You can use more powder to speed up a barrel that is slow, but it will never be as fast as a barrel that is inherently fast. You shouldn’t over-stress yourself (and your brass) by trying to duplicate the velocity someone else is getting. You must work within your barrel’s limits. Factory Ammo is a benchmark
If you own a.223 Rem or a 6.5×47 Lapua (or a 6.5 Creedmoor), a.308 Win or a.30-06 Springfield rifle, we recommend that you purchase a box of factory-loaded Lapua ammo. This ammo will shoot well (usually around half-MOA) and can be used as a baseline for determining how your barrel performs in terms of speed. [Editor’s Note: The original test took place in 2008. Your results may vary depending on the velocity of the current Lapua factory ammunition. When you finish a new 6mmBR, it is smart to chronograph a box of factory ammo. This will give you an idea of whether your barrel is slow, average or fast. You can then set your velocity goals according to that. If, for example, the factory 6BR ammunition runs between 2780 and 2790 fps, then your barrel is average. If it runs at 2820+ in 26? If it runs 2820+ in a 26? You’ve got yourself a tube that is fast.
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