Effects of Primer Weight Sorting
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- Опубликовано: 2 авг 2024
- The purpose of this video is to display the results of a primer weight sorting test. In summary, results show that there is a linear correlation between primer weight and velocity - higher primer weight, faster velocity. This is likely due to variations in compound volume and weight. There appears to be an ideal weight in terms of reliable ignition resulting in smaller standard deviations and extreme spreads. The primer manufacturer appears to set their typical compound volume to what is the most reliable ignition. Shooters looking to have the most reliable ignition should weight sort their primers and assess for the ideal primer weight to their application.
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Good test. Well thought out, executed, and presented.
Fantastic work. You put together your tests extremely well, perform them well, and analyze the results very will, and also present all 3 of those things well in your videos. Keep doing these and people will catch on to your channel eventually.
Thanks Bryan, I really like the topics and quality of your work. I think you're doing a great job. I'll buy that book when you publish it.
Good data, thank you! I'm curious what the firing order was and with what cadence the groups were fired. The large increase in velocity with primer weight could at least partially be explained by the chamber heating up. If the groups were fired in order of increasing primer weight, it would be good to see the same test done in the opposite order to see if the trend reverses or becomes less significant. Thank again!
I shot the heaviest primer first, lightest second, 2nd heaviest next, second lightest next, and so forth. I started at the tails and moved inward. I have a barrel temperature indicator on all my barrels and I watch it closely. I give the barrel time to cool between groups and never let the bullet “cook”/leave it chambered for more than 15 seconds when the chamber is warm. I do this on all of my tests to eliminate effects of barrel temperature.
@@WitchDoctorPrecision thank you!
@@WitchDoctorPrecisionIt would be very interesting to see the exact same test performed, only change would be to uniform all primer pockets to .122” per sammi for small pockets and to seat the primers to exactly .008” below the surface. This change has shown a marked improvement in precision. So, long story, I believe it will show an even more linear progression in velocities.
@@carltheriot8107 the pockets were SAMMI spec and primers seated to .008”. There is a lot of detail like this I do not put in the videos because it would make them way too long. Viewers tune in for only 7-10 minutes and if I put all that detail in, the videos would be way too long. I’ll put the details in a book when I have time to write all of this up. Thanks for tuning in!
The main gist of the weight sorting test is that you will get variable velocity with different weights. This will impact vertical dispersion significantly even at 200 yards (see my most recent primer weight test) so unless you have a very consistent lot of primers, I would sort even for short range.
Yup, I have seen the same effects. Some batches of primers better than others over the years. When going out past 600, seems like everything matters. Well Done.
Thanks once again for all of your thought and efforts. And in particular I appreciate your responsiveness to suggestions for new tests. You're a great source of knowledge.
As always Bryan, outstanding expertise !! 👏👏👏👏 Thank you !!!
Thank you for this information! This is really interesting and helpful. I wish you had another caliber to try to see if the results stay consistent.
Thanks! I’ve been looking for a video like this👍
Makes sense , more spark , more bark
Thanks!!👍🏻👍🏻👍🏻👍🏻👍🏻
Thank you Bryan for the considerable time & expense that goes into your testing.
Very interesting results which beg quite a few questions.
I noted that the velocity differences were enough to influence vertical at long range for you F-class lads , at least between the lower & higher weight range groups.
If you don't weight sort at the moment, is it something you will likely do from now on?
I've found if your willing to pay more for the br4 primers the weights are more concentrated to about 3 groups instead of 6.
Make them worth the extra $ :). I wonder if it is the same with Federal 205 and 205M? Looks like more tests on the horizon.
Thank you Bryan. I've been thinking about this and if it is something I should try. I think I will see how it works out between Federal match and CCI BR-4.
Please post the results.
If that was calm conditions, I think you need to reset your zero. : )
I didn't think there would be a POI change. When I first got my 6 PPC, I was working up a load and I shot 4, 5 shot groups with .3 difference in powder charge. POI was the same on all 4 targets. If I would have shot at the same target, all 20 rounds would have gone into the same hole. I couldn't believe it.
Now I have to weigh my 205M and see what the range is. One more test to add.
Each barrel has its own “tune window” and the one you have has a very wide tune window if 1.2 grains of powder variation all had the same POI. If the groups were very small, then you might have a “hummer” barrel. Anyway, I emphasize the POI for those who subscribe to the “velocity node” idea to show them that variations in velocity do not impact precision or POI which would be expected if velocity nodes actually existed.
Did you do any preliminary height sorting prior to weight sorting to maintain a consistent amount of anvil compression?
No, height sorting is way too impractical and my focus is on things that can be practically done. I’ve also been asked if I’ve pulled apart primers to measure every dimension and measured fires primers to see if there is anything with the hardware of the primer that accounted for the difference I found in weight. Again, my focus is on practical things…nobody is going to pull apart and put back together thousands of primers nor weight them after shooting. The results I got showing variances in velocity among the various weights was strong enough to suggest that it’s a variance in the amount of priming compound. I’m good with that and not planning any further testing. I’ve found that when I have gotten pulled down a rabbit hole, the results are insignificant. For example, in my flash hole diameter testing, I allowed myself to get pulled into a rabbit hole by some shooters who thought that a magnum primer would have a pronounced effect over a standard…well it didn’t and, in retrospect, while I thought their rationale sounded good, it wasn’t and it taught me to be careful taking the bait down these potentially insignificant rabbit holes especially among shooters who only have conjecture and no data to support their assertions. I have other testing that needs to be done and have to use my judgment to discern what is worth the effort vs what is not. In my judgment, sorting for primer height is not a worthy test but I will never dissuade somebody for testing this if they want and I will always want to see their data. I’d even help them devise the methods for the test and analyze the data but I’m not going to do that type of test myself.
Hi Bryan , i listened twice for the caliber but only got a BAT rifle and Hottenstein 65 bullets . Is it a 6 PPC ? i understand CCi 450 are small rifle magnum primers... do you know the volume of gas generated by this primer ? i dont , i am looking for the information.
Yes, 6PPC. I would online search “primer brisance” and you may find the info you seek.
I really appreciate the effort in this type of testing and analysis, Brian. As a short range group and score shooter I wonder how dramatic an effect this has on us. I know that there are lots of teen aggs shot with primers that haven't been sorted...or are those primers a different brand and therefore more consistent? Fed 205's and 205M as well as CCI Br4's are what I have used in the past and have to wonder if this is the case.
From the primer seating depth video I lit a little fire for some of my buddies:
I have done an informal poll of my fellow BR score shooters (all shooting 30br) and had them measure their primer seating depths. Those that were going to "feel" (myself, previously, included) were off by several and up to .004 difference between cases. One shooter who has recently gone to a bench mounted seater using BR4's found that he was .0005 between all his depths. He had one of the best years thus far and the only thing that changed was primer seating consistently.
Long post
Many thanks!
Mike
In my experience as a scientist, I find that one experiment, while producing large effects that inform people greatly, produces more questions and more questions than a lifetime of experimenting can answer. My mentors in science who have had the greatest impact on me have typified what I would characterize as being exemplars for science itself. My paradigm of practical testing will hopefully continue under this light. Otherwise, I haven’t been an effective exemplar in this paradigm.
As for the idea that many records have been set and matches win with primers that haven’t been sorted…sure, that is indeed the case and, frankly, I hate to be the one who displays evidence that would add more to the reloading routine (especially knowing how hard it would be for me myself to implement this with my busy life) but the data tells a tale and the base rate issue is at hand. When 500 billion groups have been shot in matches from 1940-2020, you cannot compare them to the technology of what has been shot with current load practices post 2020. I bet my last shiny nickel that if shooters followed current best practices based on evidence for loading techniques that the next 500 billion matches over the next 80 years would on average yield better results. You can either be stagnate with old tech which will yield wins or you can move forward with data-driven tech and join the tide of shooter that I believe will overall be better in the next generation.
Hey Mike, I think I actually replied to one of your comments on another channel. I had a big write up on one of the other videos that Bryan uploaded that was unfortunately lost when it was deleted and re-uploaded but I found the same thing with primers. I have always used BR4s and seated by feel. I made a tool to compare the primer depth and found that over 200 rounds in three calibers my ES was 0.004" and my SD was around 0.002". I've since picked up a hand seater with a hard stop that allows me to lower the ES to ~0.001"(and this ignores the fact that the primers range from 0.1205 to 0.1215 and pockets have some variance as well). I haven't been able to do detailed testing yet as there's about 4 feet of snow on the ground currently but I'm looking forward to doing testing with my 6PPC, 6BR and 6.5x47L to see if the consistency will have a noticeable short term effect. Bryan is sure giving us a lot more work to do isn't he!
@@MMBRM what hand seater?
@@MMBRM and please post the results here or PM me with them. The more data the merrier!
@@WitchDoctorPrecision Very well said, and why I am following all of your videos very closely. So many guys that I talk to have pretty much planted their feet in concrete...I intend to rise above that and forge ahead. I do my own machine work and have a passion for perfecting that craft as it relates to precision rifles. I have built some record setting rifles (IBS score) for shooters and look forward to more in the future! The gains that will be seen in efforts like this may not show up on one target, but the agg of the match and over the season and over the years will improve.
Excellen!
Thanks again Bryan! I've always wanted to do that test but never got around to it. That data is way more correlated than I would have expected. Very clear relationships. What primer was this? I'm just curious as I found my CCI BR4 to be much closer in weight than the distribution pictured here. While there was no correlation to group size the fact that a 30 fps deviation from standard could combine with other factors on the day and may take you outside your node for the bullet loaded with the tail end primers.
CCI450. I would like to test BR-4s and other similar “match” primers (eg, Federal 205M). What did you find with the BR-4s?
@@WitchDoctorPrecision Using a FX-120i scale and 120 total weighed with a distribution of 3.68(9), 3.70(43),3.72(43), 3.74(20), 3.76(5). So an ES of 0.8gn compared to your 1.2gn on the CCI 450. I've also found that generally the CCI BR4 has given me higher velocity which may mean the heavier weight is mostly primer compound.
@@MMBRM thanks for sharing. So it looks like the extra $ paid for the BR-4s does buy you something :)
@@WitchDoctorPrecision It does! Which is nice. I actually weighed another 100 today. These were from a new box with a different graphic design. The weight spread is the same but the distribution is fairly different. 3.68(15), 3.70(34), 3.72(16), 3.74(25), 3.76(10). My plan for now is to bundle 3.7-3.74 for my match loads and use the 3.68/3.76 for warm up/practice. There's also a possibility that day to day scale drift due to environmental factors could have an error of ~0.02gn. That last digit of resolution usually has to be taken with a bit of skepticism.
@@MMBRM yes, raw weight values are going to vary by scales but I do like how the BR-4s have less variability relative to the 450s. Just tested that today and they did much better than 450s and, like you mentioned, were much faster. I’m wondering if weight sorting is even needed with the BR-4?? Although I did find better groups with the heavier BR-4s…hmmmm…
Hi Bryan, in what order did you shoot this rounds? Because if you don't shoot these different weights in a random order, barrel heating and fouling may have an influence on the velocities. I mean you get different bullet friction between a cold clean barrel at the beginning, vs warm and and fouled at the end, giving different velocities
I just commented on somebody who asked the same thing. I shoot foulers before shooting the test rounds. I shoot different orders to eliminate order effects. For this test, I shot the heaviest first, then the lightest, then the second heaviest, and so forth. Basically I started at the tails and moved inward. I have a barrel temperature indicator and watch it closely. I let the barrel cool in between groups. I do not “cook” a bullet/leave it in a warm chamber before firing…all rounds are fired within 10 seconds of chambering and all groups are usually shot real fast. I use these procedures on all my tests to eliminate barrel temperature as a factor. I do not mention this in the videos because if I went into that amount of detail about how I control for and eliminate variables in these tests, the video would be an hour long and nobody would watch. I will save those details for the book I plan to write.
@@WitchDoctorPrecision A book ? I suppose you will tell us in a video. Do you have suggestions about good reloading& shooting books ? I've already Tony Boyer's and I'm looking for others.
@@br4713 yeah, there is so much detail that goes into these tests that I cannot put in a video because the videos need to be relatively short otherwise people will not tune in. There is a direct correlation between video length and views - the longer, the less views. A lot of people just don’t have the time. Gotta keep it short and sweet with videos but with a book, I can write it comprehensive.
The Boyer book is excellent for BR. For other interesting topics related to shooting in general, the books by Bryan Litz are really good. His stuff is more oriented to tactical and long range shooting but there are some good nuggets to information and wisdom in them.
Bryan, I watched all 3 videos in this series and I’m struggling with the results. Just focusing on velocity variations versus point of impact, 30fps variation should certainly affect POI. Additionally I didn’t expect to see that much variation in velocity versus primer weight. Typically 0.1gr of powder changes velocity about 7-10fps but 0.1gr of primer weight changed velocity 30fps. Are you certain of your charge weight consistency, brass prep, neck pressure and seating depth? Feels to me something might be skewing the results.
Yes, all else is well controlled. I actually replicated a test that showed the exact same results with a ~.1 variation in primer weight producing about 30 ft/s difference which added to my confidence in the findings. As for POI, in short range BR with a good barrel, I can get the same POI when a whole lot of things are varying including velocity differences at ~30 ft/s so these results are actually typical.
Here is the test I replicated
forum.accurateshooter.com/attachments/primer-test_weight-sorting-srp-6ppc_1-pdf.1070719/
@@WitchDoctorPrecision - Thank You for the replies and I applaud your tenacity in gathering this information! I reload with CCI 200 Large Rifle primers and do not sort primers. I attempt to control my charge weights to within 0.04gr (41.48 - 41.52) and typically see an ES around 20fps (2690-2710fps). I think you just found a large portion of my issue.. Thank You for your dedication!
Are you telling me that with that load if you don’t sort your primers you have a 32fps extreme spread?
If you sort the primers and shoot the heaviest and lightest, you will get an average velocity difference around 30 ft/s
@@WitchDoctorPrecision yes I got that. But I’m talking about not sorting. You could have a light one beside a heavy resulting in 30fps difference. Seems crazy, I’ve never sorted primers and never had such a high velocity spread
@@taylorbokshowan5713 I don’t usually sort and usually have extreme spreads in the 20s and 30s but it didn’t seem to affect precision in the short range matches. Seems like it would in long range.
@@WitchDoctorPrecision ya probably not a big difference at short range. I usually get es mid to high teens with out sorting using federal match primers
Have you thought about comparing the 3.66 group to a randomly chosen group, or a few I suppose, to see if part of the general SD we get in loads is attributed to primer compound weight and if it’s really worth sorting primers or at least eliminating the tails (something I might start doing after watching this).
Yes, I did consider that. I considered using random primers as my baseline comparison. I wish I had unlimited resources to do the most comprehensive experiments but alas I am limited (not enough brass and time in this case). However, based on the data this experiment produced, I totally agree with the approach you mention to eliminate the tails. That would definitely hone you down to better ballistics and put you in line with the primer manufacturer’s ideal weight. From there you can assess the impact of the small variations on the target and then choose the one with the best groups and consistency in groups.
You need to use the individual data to plot your chart, and apply a modelled best fit. Plotting average data tells you v little.
Your std dev demos this v clearly.
You then need to do an ANOVA analysis on each group of data.
I suspect the ANOVA might show that there is no statistically valid difference.
You can do all this in MS Excel, the the Analysis Add-in
Good luck in delving into some proper statistics