Found the post where I contacted Lapua customer service...
I asked:
By what procedure does Lapua determine if a lot of 22lr coming off the assembly line
is X-act, Midas+ or CenterX. The question came up in an online discussion.
A previous article related that it's accomplished by shooting random samples,
from each batch, from a number of barreled actions and checking muzzle velocities
for standard deviation and extreme spread.
Could you describe the process and the numbers that define the grading?
Hi Justin,
You're on the right track, but I'm afraid I can't divulge the exact nature of the testing
in terms of standards that you're after. Proprietary, and strictly in-house info there.
I will say that every run of ammo, either Lapua or S-K, is accuracy tested in a series of five 10-shot groups,
as well as a 50-shot composite. The SD and ES are measured and are required to fall within a strict set of parameters,
but ultimately, it's accuracy that makes the final determination. Those that pass this initial testing
and show the best promise, are then retested. There are repeats of this same testing in several different test rifles,
in essence winnowing down the field. If it passes that testing at a certain level of accuracy,
it becomes X-Act, or is downgraded to Midas+ or Center-X, depending on where the measurements fall.
Testing of rimfires is problematic, as the ammunition tends to be so rifle specific and,
for lack of a better term, temperamental. In doing such testing at one of our Service Centers
in either Germany, Finland or Mesa, AZ, I've seen countless examples of Center-X or Midas+ outshooting X-Act,
regardless of how they tested during acceptance testing.
In those cases, count yourself fortunate that your rifle prefers the less expensive stuff.
The bottom line is, you simply can't rate match grade rimfire ammo from best to worst
strictly by the showing it makes in the test rifles. It's a start,
but you ultimately HAVE to test the lot in your particular rifle to know.
I hope this answers your, at least as far as I can answer it
without violating the specifically proprietary methods and specs.
If there's anything more we can do to be of service,
please don't hesitate to let us know. As always, we'll be glad to help.
Sincerely,
Kevin Thomas
Sales Manager
Nammo Commerical Ammunition
I came up with my own conclusion based on the information provided.
It's rimfire and the manufacturing process allows variations in quality and assembly of the components.
Quality control and the testing/sampling done at the factory determines the labeling.
What if the portion of the batch sampled and tested shows excellent results
but the remainder had a hiccup during the rest of the run, you won't know until you shoot it.
It may be labeled X-Act, but it produces trajectories like CCI SV.
A slight misalignment in the bullet seating, brass dimensions or a tiny blockage in the primer feed
can cause mv's to spread and trajectories to wander off on undesired tangents.
A company representative can't say that, it's not in the job description.
On the other side of the coin, what happens if the factory sampling shows poorer results?
It gets labeled as midgrade ammunition and sold at much cheaper prices.
But when you get your hands on it, it turns out that the factory tested the wrong portion of the batch.
That's when you have lot numbers of CenterX that are better than all the other Lapua offerings.
Same thing happens with the RWS and Eley brands.
Match ammunition is the best produced by the factory, as tested at the factory.
It gets boxed, labeled and sold as the best offered by the brand.
Further testing by the purchaser decides if it really is match ammo
or just expensive practice ammunition.
