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
