With a little spare time on our hands, and a whole lot of bullets, we set out to measure the consistency of a few popular 6.5 bullets. We have shot the Sierra 142 for some time now, and they are great performers in our rifles. The Lapua 139 shoots equally well. We have not fired any of the Berger 130 or 140 grainers yet, as they have just arrived to the shop. These will be shot for groups at long range and all 4 will be compared in an article very soon.
The BC’s of these bullets are quite high, the whole reason for shooting a 6.5 rifle. In our test rifle, a .260 Ackley, velocities up to 3000 can be obtained, but case life suffers. So, we keep the throttle closed a little bit and shoot 2900 with these loads. The accuracy is excellent, and case life is no longer an issue. The BC of the Sierra 142 is .595, the Lapua 139 is .600; the Berger 130 is .600; and the Berger 140 is a whopping .640!!
In this image, you can see the lengths of the bullets really don’t vary much. Even the 130 is lengthy – which explains the .600 BC ! You can see the bearing surface is a little shorter, but the nose is longer for the weight of this bullet. We randomly pulled 10 of each bullet to sample, not enough to be statistically significant, but we weren’t doing this for 100 bullets. (any volunteers?)
Below are the results of the measurement tests. We measured overall length (just to show you why you shouldn’t seat bullets measuring overall lengths) and measured ogive to base. We would have like to measure bearing surface, but were not set up for the task.
You can see from this overall length chart vs. the ogive to base chart, anyone seating off the nose of a bullet is asking for trouble. The Bergers were very consistent overall, then came the Lapuas, then in last place the Sierras. The funny thing is, the Sierras shoot just great, but they sure don’t measure out too well.
We’re looking forward to part 2, the field testing. Although any shooting is only comparative for the exact rifle and shooter, it should be an interesting article ! Stay tuned!