Small pistol Match primers
- Thread starter Grant 14
- Start date
chris in va
New member
If you can find SPP of any flavor right now, get them.
Match primers are made by the most experienced primer crew members; no newbies or learners. The idea is that will improve the odds of consistency being good. However, in actual testing, you find that sometimes the less experienced people can get on a roll and actually turn out the more consistent product. I've seen tests where that happened. But the odds are still with the match primers being more consistent.
That said, it is about more consistency in a surprisingly inconsistent item. Getting those tiny charges held to close tolerances in a manufacturing environment is not easy. The Courtney's set up primer blast measuring and found the standard deviation to be significant and that sorting Federal 210Ms (IIRC) by weight to the nearest milligram (about 0.015 grains) cut that in half.
That said, it is about more consistency in a surprisingly inconsistent item. Getting those tiny charges held to close tolerances in a manufacturing environment is not easy. The Courtney's set up primer blast measuring and found the standard deviation to be significant and that sorting Federal 210Ms (IIRC) by weight to the nearest milligram (about 0.015 grains) cut that in half.
jetinteriorguy
New member
Just when I thought we were out of rabbit holes.
and the rabbit hole gets deeperYep! 
. When I read that I got a big grin because I bought an auto-calibrating analytical balance last year that resolves 0.1 mg. I've got a box of 1000 BR2's and powder and 150 pieces of new Lapua brass in 308W. I was going to test weighed primers vs. randomly selected ones with it last year, but the cold weather beat me to it by a couple of days. In the spring I'll do that one.
. When I read that I got a big grin because I bought an auto-calibrating analytical balance last year that resolves 0.1 mg. I've got a box of 1000 BR2's and powder and 150 pieces of new Lapua brass in 308W. I was going to test weighed primers vs. randomly selected ones with it last year, but the cold weather beat me to it by a couple of days. In the spring I'll do that one.Yep!
A better test would be to compare primers of a single weight to primers that have many different weights. Here you're comparing consistent weight primers to inconsistent weight primers.
The problem with 'randomly selected' primers is that they could all be the same weight. And you wouldn't know. So the results would be meaningless. Since weight is the variable you are testing, it needs to be measured.
I am using a method out of the statistical quality control textbook. The reason for testing randomly selected primers is not to bias the result with the extreme spread, whose performance will not be representative of the advantage gained by taking the time to sort by weight as compared to just using the primers out of the box. That's what I want to learn. What will I typically get out of it? I also want to understand what the distribution looks like.
Following good statistical practice, I took all ten trays out of the unopened box of 1000 and numbered them 0 through 9 at the top left corner and established a consistent numbering scheme from left-to-right and top-to-bottom. I then used Excel's random number generator to provide 30 unique numbers between 1 and 1000 and pulled those primer numbers from the trays to make up my random sample. The odds against this method providing 30 primers all the same when the whole box is not all the same are very low. The only underlying assumption is that the weight distribution of the primer charges is either normal or a blend of several normal distributions from different technicians. Either way, a good idea of the distribution should result.
That was the easy part. The next step is the much more arduous task of weighing as many of the remaining 970 it takes to find 30 that are as identical as possible. I haven't done that yet. I'll report on the rest of the experiment and the variable control methods I employ when I get the results.
Following good statistical practice, I took all ten trays out of the unopened box of 1000 and numbered them 0 through 9 at the top left corner and established a consistent numbering scheme from left-to-right and top-to-bottom. I then used Excel's random number generator to provide 30 unique numbers between 1 and 1000 and pulled those primer numbers from the trays to make up my random sample. The odds against this method providing 30 primers all the same when the whole box is not all the same are very low. The only underlying assumption is that the weight distribution of the primer charges is either normal or a blend of several normal distributions from different technicians. Either way, a good idea of the distribution should result.
That was the easy part. The next step is the much more arduous task of weighing as many of the remaining 970 it takes to find 30 that are as identical as possible. I haven't done that yet. I'll report on the rest of the experiment and the variable control methods I employ when I get the results.
I checked 200 CCI 400's yesterday just to see the variance. 98% were within seven milligrams. I am going to run down to Harbor Freight tomorrow and get some small plastic storage trays. Nothing scientific about my test, just going to load my match ammo for the next three or four matches with the same weight and see what happens. I have been shooting 194 - 196's consistently for the last four months regardless of conditions or yardage. If I can pick up a point or two I will continue to sort, if not why bother.
No doubt, Werner Heisenberg and Nils Bohr would have been much chagrined to learn from you that statistical distributions have no bearing on the science of why and how things are as they are and do what they do.
What you have described is a false dichotomy. The actual difference between our approaches isn't how scientific* they are. Rather, the difference is that when, as one must at the beginning of the design of a scientific experiment, you have to decide what its purpose is, we came up with two different purposes.
*A scientific test is simply one that is consistent with the scientific method of inquiry. That depends on how reproducibly systematic the methodology is and on whether it succeeds in proving or disproving a hypothesis. My hypothesis is there will be a discernable difference in velocity consistency between cartridges fired by the weighed and unweighed primers to at least 95% confidence, as judged with a t-test. I additionally want to determine how often that variation will take a velocity outside an established velocity flat spot range for the gun and ammunition combination I use, thus to affect the point of impact on a distant target. I will describe this in detail when I have finished conducting and writing up the test.
What you have described is a false dichotomy. The actual difference between our approaches isn't how scientific* they are. Rather, the difference is that when, as one must at the beginning of the design of a scientific experiment, you have to decide what its purpose is, we came up with two different purposes.
*A scientific test is simply one that is consistent with the scientific method of inquiry. That depends on how reproducibly systematic the methodology is and on whether it succeeds in proving or disproving a hypothesis. My hypothesis is there will be a discernable difference in velocity consistency between cartridges fired by the weighed and unweighed primers to at least 95% confidence, as judged with a t-test. I additionally want to determine how often that variation will take a velocity outside an established velocity flat spot range for the gun and ammunition combination I use, thus to affect the point of impact on a distant target. I will describe this in detail when I have finished conducting and writing up the test.
Fine, but you won't know why your results are the way they are because you haven't measured the one variable that might be responsible - primer weight. Isn't that the hypothesis behind this whole exercise = Does primer weight affect velocity?
The weight of the randomly selected primers could be exactly the same as your weighed primers. In that case your results, whether they show the velocity is the same or not, will not have an explanation for why the results are the same or not. When someone asks you why the speeds are the same or not the same, your best answer will be - I don't know.
Your example of purposeful or random primer selection ask if the results are the same or not in an attempt to address how people should select primers. That's fine but doesn't answer the question of whether primer weight matters in producing the same speed or not. If you know that the primer weight does or does not matter, that tells you if one should bother to weigh them in the first place.
The weight of the randomly selected primers could be exactly the same as your weighed primers. In that case your results, whether they show the velocity is the same or not, will not have an explanation for why the results are the same or not. When someone asks you why the speeds are the same or not the same, your best answer will be - I don't know.
Your example of purposeful or random primer selection ask if the results are the same or not in an attempt to address how people should select primers. That's fine but doesn't answer the question of whether primer weight matters in producing the same speed or not. If you know that the primer weight does or does not matter, that tells you if one should bother to weigh them in the first place.
Ahhh! You thought I wasn't planning to weigh the random sample. Everything gets weighed on the Torbal and marked on the case the primer goes into. That's the starting point. The weight distributions found by the Courtneys varied with primer type and I expect mine will be different, still, so it has to be determined. What makes finding the same-weight primers out of the remaining ones a much bigger pain is I have to lay them all out by weight on a grid until I get a value that has enough members for the experiment. That's the weighing I haven't done yet.
There are a number of other variable controls involved in the experiment that I haven't described. I'll leave them for the write-up.
There are a number of other variable controls involved in the experiment that I haven't described. I'll leave them for the write-up.
Sorted my first two humdred CCI 400's this afternoon, boring would be a compliment. I used bead storage craft jars from wally world and my A&D. Nice bell curve developing,with the low at 218 mg high is 227 mg with the peak at 223 or 224 mg. I will make a thread with a spreadsheet and graph when I get 500 sorted.
I am thinking of way to make the test a little more decisive. I have a almost new 6BR barrel on a tactical rifle in a MDT chassis that still needs a load workup. Thinking of 8208 and 107 Noslers to save my Bergers and Varget for matches. Once I do the load workup I may try five groups of five rounds each of unsorted and five groups of sorted at 300 or 600 shot round robin if I can find a cloudy windless day. Any thoughts ?
I am thinking of way to make the test a little more decisive. I have a almost new 6BR barrel on a tactical rifle in a MDT chassis that still needs a load workup. Thinking of 8208 and 107 Noslers to save my Bergers and Varget for matches. Once I do the load workup I may try five groups of five rounds each of unsorted and five groups of sorted at 300 or 600 shot round robin if I can find a cloudy windless day. Any thoughts ?
Here is a great video on small pistol primers, small pistol magnum primers and small rifle primers. This guy shows all the pressures data on the different primers using same powder , brass . It is under 10 minutes but great information during this times when supplies are non existent .
https://www.youtube.com/watch?v=NGVRGsoOr6k
https://www.youtube.com/watch?v=NGVRGsoOr6k