Round count to determine the best lot# ?
- Thread starter obx22
- Start date
Sometimes 5-10 is enough to know a lot is crap and can still get faked out with 50 from the one "good" box in a brick.
5-10 to know it's bad. 20-30 to know it's good.
Oh for Christ sake guys are spending 15-35 dollars a box for 22 ammo and are worried about lot variation? And 1500 rnds down a bbl BEFORE testing man we have wayyyyyy too much expendable cash!!!!
A lot of .22LR match ammo usually is about four to six cases in size, sometimes a little less or more. That's 20,000 to 30,000 rounds.
In a .22LR match ammo population measured in tens of thousands, how many should be looked at before making an evaluation? What level of confidence is required? The higher the level of confidence in the results, the larger the sample tested is required.
In other words, the smaller the testing sample, the lower the confidence level in its accuracy. Testing only ten or 50 rounds out of 20,000 or 30,000 is unreliable. Of course if it shoots lousy, it is easily disqualified.
A very few lots will be so consistent from one round to the next that there are no outliers, no "strays" -- or no rounds that don't go where they should. A very few will have quite a few outliers. The rest -- the majority -- will be somewhere in between, with more or fewer rounds that don't go where they should. Of course, the rounds that don't go where they should can themselves vary by how much they stray.
If reliable results are desired, it's therefore better to test hundreds of rounds rather than dozens.
In a .22LR match ammo population measured in tens of thousands, how many should be looked at before making an evaluation? What level of confidence is required? The higher the level of confidence in the results, the larger the sample tested is required.
In other words, the smaller the testing sample, the lower the confidence level in its accuracy. Testing only ten or 50 rounds out of 20,000 or 30,000 is unreliable. Of course if it shoots lousy, it is easily disqualified.
A very few lots will be so consistent from one round to the next that there are no outliers, no "strays" -- or no rounds that don't go where they should. A very few will have quite a few outliers. The rest -- the majority -- will be somewhere in between, with more or fewer rounds that don't go where they should. Of course, the rounds that don't go where they should can themselves vary by how much they stray.
If reliable results are desired, it's therefore better to test hundreds of rounds rather than dozens.
There's also guys preaching that you have to scrub the bore clean when switching ammo brands/variety. Otherwise the difference in lubes and lead can skew data.
I agree with this one! if switching brand either clean the barrel (no scrubbing required, just wet patch and a dry to ret rid of lube) , or just shoot 10 rounds to lay down new lube base.
When I had my Vudoo tested at Lapua/Capstone's Arizona center in 2020, 50-yard results of ten-round 50-yard groups of each tested lot (minimum of eight lots) were compared. Then 20 additional rounds of the best lots were fired and results compared.
So call it 10 shots to eliminate and 30 shots to confirm. Note that Lapua's test regimen gets pretty deep in the statistical weeds.
I bought two cases of that "best" Center-X, and it has performed very well in every rifle in which I've used it. I don't have much of it left. The test centers ONLY test Center-X, Midas+, and X-Act... and I found a couple of different lots of Long Range bought from a buddy to perform very well at 200 yards or more, and comparable to my C-X at 50-100. He said every lot of Long Range he's used has done well. So I bought half a case of Long Range. Here's hoping it does well.
Don't want to spend the $$? No worries. CZs, Tikkas, and Bergaras can do fine with $8-per-box SK Standard+.
So call it 10 shots to eliminate and 30 shots to confirm. Note that Lapua's test regimen gets pretty deep in the statistical weeds.
I bought two cases of that "best" Center-X, and it has performed very well in every rifle in which I've used it. I don't have much of it left. The test centers ONLY test Center-X, Midas+, and X-Act... and I found a couple of different lots of Long Range bought from a buddy to perform very well at 200 yards or more, and comparable to my C-X at 50-100. He said every lot of Long Range he's used has done well. So I bought half a case of Long Range. Here's hoping it does well.
Well, yes. If we're going to spend that much for a box of ammo, we want optimum performance. And there IS lot-to-lot variation, even out of $3000-5000 rifles (not including optics). In my conversations with the gentleman who tested my rifle, I learned that the very best lots never see the retail light of day from the factory, because the world-class competitors test their rifles at the factory and buy the entire lot when a superb one is found.
Don't want to spend the $$? No worries. CZs, Tikkas, and Bergaras can do fine with $8-per-box SK Standard+.
I got half a case of Super Long Range, will see if I like it as well at 100 as my Midas and centerX. Tried a brick of SLR and Xact and the Xact about the same as my Midas but the SLR was better consistently.
Just out of curiosity when these Factory tests are done to find the best lot why do they shoot at 50? Most good quality rifles will shoot almost one holers why not test to 100 that sorts the men from the boys.
They test electronic targets, the 50 and 100 are the same shots, just "trapped" at each distance.
Yup, we've found all lots of SLR shot the same and RWS R50 is another ammo that is equal to SLR for our Longrange matches.
Topstrap
My new lot of Long Range is superb.
I got out today to test my new half-case of Lapua Long Range. It was a cold (40s F.), pretty raw day with 2-5mph wind from 2 o'clock; I got initial 50-yard and 100-yard confirmation done and then moved to the 550 range where I shot 200, 300, and 400 yard plates in increasingly heavy drizzle.
I think I've hit the rimfire lottery. I only fired 70 rounds today, but it looks like this lot of Long Range could be the most accurate rimfire ammo I've ever fired.
- I fired four 5-round groups at 50 yards; one of those had all 5 in a .3" edge-to-edge hole, and the other three were close to that.
- I fired another 15 rounds at 100; very promising with two or three rounds of each 5-shot group falling in 1/2" or less and the other one or two moved as much as another 1/2" by the wind.
- It was getting dark and the rain increasing when I split 35 shots across 200, 300, and 400-yard plates. In short, my lot-tested Center-X never performed that well at 300 and 400. Normally, if there's much breeze at all, 400-yard shots become largely luck. I hit at least half the shots on a 12" plate out there today... I was cold, getting wet, ready to leave.
When I first arrived, there was another gentleman on the line with a CZ-457 in an MDT chassis and a 24" or so straight-cylinder barrel. He was fussing with batches of Long Range and Super Long Range; said neither one performed as well as his Center-X.
- I shot 10 rounds of his Long Range out of my Vudoo. It wasn't as tight as my lot of Long Range, but it was ok and also the sample sizes for both mine and his were relatively small.
- His Super Long Range was definitely disappointing; it performed about like I would expect a so-so lot SK Standard+ to do.
Fwiw.
