Rimfire Central Firearm Forum banner
  • Whether you're a greenhorn or a seasoned veteran, your collection's next piece is at Bass Pro Shops. Shop Now.

    Advertisement

My Experience at the Lapua Rimfire Test Center

1 reading
11K views 72 replies 33 participants last post by  StephenBachiler  
#1 ·
Last month I took my match 457 VPT w/24" barrel to the Lapua Test Center in Mesa, AZ. For those who don't know Arizona is mostly desert and this facility is on the outskirts of Mesa at the end of a dead end road. Lots of desert around here!
There was a security gate at the entrance and the guard was new, so there were issues even getting in.

My tester/contact was Devan Stricker and he finally showed up at the gate and escorted me in. I was told that the facility (Nammo) has many contracts with foreign governments, and that is the reason for the security.

We first went into a small shop like building where Devan took my barreled action out of my rifle and mounted it their testing fixture. We then went across the lot to the testing site where the tunnel could actually be seen above ground. It is made from 4ft (?) diameter concrete pipe. The building is a short sea container with lots of exterior insulation, for heat as I was told. It gets HOT there!

Image

Here it is all set up ready to shoot. They have electronic targets at 50 and 100 meters and a computer screen just to the right of this is where it is all monitored. He brought out all available lots of ammo that was to be tested, in my case Center X, of which he had 8 or 9. He fouled the barrel with 5 or ten shots and then began the tests. We started with 10 shots of SK Long Range Match that I had brought as a baseline. It wasn't very impressive.

The computer centered the first shot and then recorded each shot after that based on that. It would also encircle the group and note the diameter. Afterwards, the computer would generate more data and overlay the second ten shot group (if tested) over the first to see what a twenty shot group would look like. It also generated a bar chart to help see the distance from center the shots were. Too much information to digest the first time through. Next time I will be more knowledgeable.

Working with just a five round magazine, if a lot wasn't showing promise after five rounds he would put it aside and move on. After shooting 10 rounds through all the remaining lots, he would go back through and shoot another 10 of the best looking groups.

After completion of shooting, the computer would generate all the data and he would print it all out, and the option of purchasing was made with no real timeline on the decision. I was very pleased with the whole experience and feel like I will go back soon to test another rifle and maybe some different lots of ammo in this rifle.

Did I miss anything? Probably, and if so I will try to answer any questions.

Richard
 
#2 ·
Very nice description of how it all goes,I too followed two old Anschutz 54's and it went very much as you described even the gate experience. The groups are measured outside to outside also and that increases size almost a 1/4" so a 13mm group is indeed impressive, but the groups don't look very impressive on paper because they clearly show where each projectile crossed the screen at least in my rifles the bullet doesn't follow exactly in the path of the previous.

Sent from my SM-G960U using Tapatalk
 
#46 ·
Very nice description of how it all goes,I too followed two old Anschutz 54's and it went very much as you described even the gate experience. The groups are measured outside to outside also and that increases size almost a 1/4" so a 13mm group is indeed impressive, but the groups don't look very impressive on paper because they clearly show where each projectile crossed the screen at least in my rifles the bullet doesn't follow exactly in the path of the previous.

Sent from my SM-G960U using Tapatalk
Hi - I've been following this thread (and saving excerpts) and appreciate all the info rckendall has presented, as well as the explanations all have supplemented. I just am confused with the above post RE group size. The charts seem to me to show in the lower-right corner the overall group size, around 20mm, while the DMAX value shows the actual Center-to-Center group size, being in the 11-19mm (3/8 - 3/4") range. Am I mis-interpreting this data?
 
#6 ·
AS I remember, they didn't specify except that the rifle has at least 200 rounds through it. Mine was clean of course!

So the results?


Sent from my iPhone using Tapatalk
I'll post a couple sheets of the results I left with. It may or may not make sense. It didn't to me until I called and asked for an explanation, which he kindly provided. That help a lot.

Image

Image

I couldn't figure out how to post PDF files so I had to take pictures of them. Not the best quality but best I could do just now?
 

Attachments

#13 ·
Here is a good site for turning pdfs to jpeg.
Love you. 2 hours ago I had to photo my word doc in order to create a JPG. This was a great way and quick! Thanks
 
#10 ·
It was @BowChamp who encouraged me to post this, I thought most folks had seen or heard about it before, as it certainly isn't a new thing.
Are the results in post #6 all at 50 meters?

Lot 28557/601231 at the top of the first computer representation has two ten-shot groups, the one on left at 16.91mm and the one on the right at 20.66mm. Was this the best lot tested in the rifle?
Yes, that lot was the best and the one I purchased. As I gave credit to @BowChamp for the encouragement to post this, I will point out the correction that @Appalachian2 made regarding these two 10 shot groups that are overlayed on the second sheet. It is not a twenty shot group, but two 10 shot groups.

The process was that we shot all lots with 10 shots if they showed promise after 5 shots. Then we selected a few to shoot another 10 shot group to see if they opened up. They all did! The best was, as you say, 16.96mm to 20.66mm. That is over 1/8" and they all got bigger. Does that show that a clean barrel shoots better? When that test was shot there was around 100 shots down the barrel.

All shots on these pages were at 50 meters as depicted by Remarks: 50M-Kendall
 
#19 ·
Sorry, I really don't know what DHH means either. Maybe I'll learn next time I go, or someone else (@Appalachian2) will chime in?

What I did learn about the bar charts was that the bars furthest to the left were closer to center on the target. The fourth set down shows that pretty clearly. There are 19 shots pretty much to the left and one flyer to the right, which shows on the target. Also, I was told that most CZs attain a mean value of 10.3-10.4 and my first set is right in the middle at 10.35. But I have no idea what the numbers 9.9 and 10.9 mean?!
Did I mention information overload?
 
#17 ·
Those results are slightly better than the two 457’s that I’ve had tested, but a couple mm’s bigger than the 452 I had tested. I’ll be there again Monday with a third 457. In the three times that I’ve tested the second 10 shot groups were significantly bigger with all lots and all rifles. I think you’re right about the rifle being dirtier by that point. I know for sure that in at least two of mine the accuracy degrades after about 80-100 rounds. I think this time I’ll request to run a patch or two and foul again before shooting the second ten round groups. I know the rifle I’m taking this time only requires 7-9 rounds fired after cleaning before it’s ready to roll.
 
#31 ·
Overload!!! :ROFLMAO: :ROFLMAO: Yep I understand...it all looks like Greek to me as well. :D

Do you know what number is the lot #?

I looked at the Center X i have on hand and some of the numbers m6011231atch.
I don't know what all the numbers mean, but what I was told was: Put a 3 before the first number and use 3 digits to determine the velocity in meters. Example from test number 1 (28557.601231): 328 m/s
The second number (601231) is the lot number.
 
#21 ·
DHH means distance from hit to hit. When I sent a rifle to Mesa I was emailed a “definitions and explanation” pdf. I must have deleted it. If I remember I’ll ask for another Monday. I can’t say exactly what the mean radius is, but as I understood it (or didn’t) it values more what percentage of the entire group was in the center of the group. Don’t quote me on that.
I thought about posting up some of my results, but didn’t want to thread hijack.
 
#28 ·
DHH means distance from hit to hit. When I sent a rifle to Mesa I was emailed a “definitions and explanation” pdf. I must have deleted it. If I remember I’ll ask for another Monday. I can’t say exactly what the mean radius is, but as I understood it (or didn’t) it values more what percentage of the entire group was in the center of the group. Don’t quote me on that.
I thought about posting up some of my results, but didn’t want to thread hijack.
Now that the topic is being discussed, please post your results, either here or separately, there seems to be lots of interest!
 
#23 ·
Regarding whether larger second ten-shot groups were the result of too dirty a barrel or not, it's worth noting in a very recently cleaned barrel such as the OP's, at 50 meters it shouldn't matter significantly whether a CZ factory barrel has shot 100 or 200 rounds.

The OP had eight different lots tested. After initially fouling with ten shots, a maximum of 80 rounds are needed initially, ten for each lot that wasn't quickly rejected for poor results. If each lot had a second ten-shot group, the total number of rounds shot would be 160 for the eight lots. But fewer rounds were tested, as the information in post #6 shows.

The difference in group size is more likely attributable to ammo variation. In other words, each random ten rounds may produce groups that vary in size, with some better or worse than others. In a factory CZ barrel, few lots will produce ten shot groups that are consistently the same size.

For those who might say that the second groups always seem larger, it's important to keep in mind that all lots that produced unacceptably large ten-shot groups were never given the chance to produce a potentially better second group.

Regarding the meaning of the various terms or abbreviations used in the target information, see below.

 
#24 ·
Regarding whether larger second ten-shot groups were the result of too dirty a barrel or not, it's worth noting in a very recently cleaned barrel such as the OP's, at 50 meters it shouldn't matter significantly whether a CZ factory barrel has shot 100 or 200 rounds.

The OP had eight different lots tested. After initially fouling with ten shots, a maximum of 80 rounds are needed initially, ten for each lot that wasn't quickly rejected for poor results. If each lot had a second ten-shot group, the total number of rounds shot would be 160 for the eight lots. But fewer rounds were tested, as the information in post #6 shows.

The difference in group size is more likely attributable to ammo variation. In other words, each random ten rounds may produce groups that vary in size, with some better or worse than others. In a factory CZ barrel, few lots will produce ten shot groups that are consistently the same size.

For those who might say that the second groups always seem larger, it's important to keep in mind that all lots that produced unacceptably large ten-shot groups were never given the chance to produce a potentially better second group.

Regarding the meaning of the various terms or abbreviations used in the target information, see below.

Thank you for the abbreviation definitions. (y)

Now maybe I can figure it out. :unsure:
 
#51 ·
This is the post I made last year about my trip there (Ohio). Thought I had posted more but this is all I could find. Should have been some pages on my CZ@1 but gone now.


chuck40219