Does Primer Seating Depth Matter?

orkan

Primal Rights, Inc.
Banned !
Minuteman
  • Oct 27, 2008
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    South Dakota, USA
    www.primalrights.com
    Blake with Reloading All Day asked me that question a while back, and I told him "absolutely, yes, unequivocally it does." Then that led to a lot more questions, which I answered best I could and then he set out to create an article on the topic. He did a pretty good job of it.


    I thought it might be a good read for some of you that might not already know about this.

    I also found it cool that he was able to run our CPS in-between clicks to achieve a consistent .0005" (five ten thousandths) adjustment.
     
    Here are the "results" from TFA :
    • -0.0000 SD of 6, ES of 12
    • -0.0005 SD of 2, ES of 5
    • -0.001 SD of 1, ES of 1
    • -0.0015 SD of 8 and ES of 15
    • -0.002 SD of 4 and ES of 8.
    So he is varying primer seating depths, incrementing by 0.0005", comparing estimates of variance in velocity... based on 3 samples each?

    Author should re-run that exact experiment 10 more times and observe: does the "sweet spot" remain consistently at -0.001" ? Or does it wander around, randomly, aimlessly, and unexpectedly.
     
    Here are the "results" from TFA :
    • -0.0000 SD of 6, ES of 12
    • -0.0005 SD of 2, ES of 5
    • -0.001 SD of 1, ES of 1
    • -0.0015 SD of 8 and ES of 15
    • -0.002 SD of 4 and ES of 8.
    So he is varying primer seating depths, incrementing by 0.0005", comparing estimates of variance in velocity... based on 3 samples each?

    Author should re-run that exact experiment 10 more times and observe: does the "sweet spot" remain consistently at -0.001" ? Or does it wander around, randomly, aimlessly, and unexpectedly.
    Yep. A sample size of 3 is not worth much more than random.
     
    Depends on how meticulous he is on his brass prep and powder drop.

    If this is a known load with same lots of components, he is very meticulous with his methods, and this load has repeatedly shown very stable sd/es, then the results are enough to conclude it is possible and worthy of more work and data points.
     
    When I’m being meticulous and want to make sure everything is the same (shoulder, neck tension, seating pressure) and use the proper tools to measure them, my 3-5 shot strings are very reflective of 10-20 shot strings.

    If you control all the variables tightly, the need for longer strings becomes less important.
     
    Funny how statistics matter when drawing conclusions.

    So, if the brass is consistent, the neck tension is the same, the seating pressure/friction is consistent, the powder weight is within a kernel, and the bullets are consistent, and the chrono has been proven to be functioning properly.....

    Educate us on what could cause an inconsistent shot?

    And not just the talking head “that’s just not enough.” Tell us what will make the data unreliable?

    And please share when you have done all of the above and your data varied substantially from 3-5 shot strings vs 10-20 shot strings.
     
    Not to mention, he explains all this.
     

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    Some people only look for what they can't get out of something. Others look for what they can get out of it. Others obviously don't even read the article at all.

    The guy just told you that extremely small 5 ten thousandths adjustments to primer seating depth can have an impact on ES/SD and actual performance on target. You then mistakenly think the burden of proof falls on Blake @ Reloading all day. When he asked me about it, and received my answer, he was skeptical... but remained respectful. More importantly, he set in motion to prove or disprove it for himself, rather than dismiss it outright. There is a difference between discovery and personal discovery. Discovery is something that you're the first person to know, ever. Personal discovery is something others know, but you didn't. This isn't a discovery. I've been talking about the importance of seating depth since before our CPS launched 6 years ago. When I discovered it, then too it was a personal discovery rather than real discovery. Others before me made the actual discovery. I felt it so important that I designed and patented a totally new priming system for the sake of it.

    People did not want to believe. More importantly, they were too lazy to test it for themselves. Even today, obviously, people still don't want to believe. Well, no matter how compelling an argument we make for primer seating depth importance, there will be people claiming it doesn't matter. They'll claim our proof is not relevant, and they of course won't have any proof because they'll claim the burden of proof is on us. lol

    So lets dispense with the false realities, shall we? The burden of finding out if you benefit personally from this is on you. The fact that primer seating depth affects ignition to the point where it will affect ES/SD is not a theory, it is a fact. Whether you can shoot small enough to see benefit from it is your personal variable, and does not change the facts.

    Since I am the creator of the CPS, and it is the ONLY tool available which can resolve this small of an adjustment, I understand the skepticism when I make the claim for years on end. People think it's just a sales tactic. They don't know me, so I can forgive that. It's good to be skeptical. However, years have gone by and many others have also stressed the importance of primer seating depth. The time for being skeptical is probably long passed. Optimal Primer Seating Depth testing is beneficial. This is a fact.

    Optimal Charge Weight
    Optimal Bullet Seating Depth
    Optimal Primer Seating Depth

    That's the order, and its just as simple to test as bullet seating depth. This is obviously inclusive of proper brass prep to ensure a uniform starting point with high quality uniform components. Suffice it to say, I have had confirmation on this importance of this from world class shooters in Benchrest, F-class, and PRS/NRL. While that level of precision might not be necessary to win field matches... those shooters are happy to see it none the less. Heading to a match with a rifle shooting five shots in one hole is a nice confidence boost.

    If everything else in your reloading ecosystem is at its apex, but you aren't doing this... then you are leaving performance on the table. Performance that is very easy to pick up if you have the right tool and the right mindset. If you can get another tenth of an inch or quarter of an inch out of your groups by doing it... you might enjoy that.
     
    Seems like some/most in the benchrest community just use the Sinclair primer pocket & flash hole uniformer tool - seems to work for those using those tools and shooting tiny groups. I have them and use them with a small Ryobi cordless screwdriver. No complaints.

    I was typing as orkan posted - my post might seem to some as a smart ass reply to his - it's not, just posted what I know from the time I shot benchrest and what I saw used by the shooters mentoring me. I got the impression from those helping me that uniforming the primer pockets was important - using quality brass such as Lapua, one usually didn't find any signs of a burr in the flash hole and the primer pockets were good too, but they ran everything through the process just to make sure.
     
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    I seat primers to the bottom of the primer pocket using a 21st Century hand primer. I then check with my finger To make sure they seated below flush.

    I have found that there are some primer/case combinations that do not go well together where it is hard to seat the primer and tell when it has bottomed out. (Currently Norma 6.5 Creedmoor with FC210M)

    Uniforming the bottom of the primer pocket does not help with this issue because it it entirely due to the side walls being too tight. How much? Not much. Maybe they have a taper to them. Who knows.

    So it is important to have a primer/case combination where the primer seats smoothly and you can feel it bottom out. Because if you cannot, then any depth testing is invalid.
     
    I have a CPS and much prefer it to any other method I've used for priming. But I was surprised by the test matrix and how limited the seating depth was changed. Maybe it's just me, but I'm seating way deeper than 0.000 - 0.002" below flush with SRP brass. I used to use the priming feature of the Forster Co-Ax, which would yield a -0.007" depth with CCI450s and 6.5x47L Lapua brass (untouched primer pocket). So I target a similar depth with the CPS and haven't had any issues.

    I was hoping the author was going to explore more crush. Hell, isn't -0.002" in this case essentially zero crush? " In this case, I uniformed them to -0.1215". I then took the primers themselves and measured those to be exactly 0.119" from the bottom of the cup to the top of the anvil itself by using the Accuracy one primer depth gauge. "

    I also wonder what effect, if any, brass headspace has? If your virgin or sized brass isn't within +/- 0.0005" headspace, that would introduce another variable as the firing pin will be moving the cartridge in the chamber more or less before the energy is transmitted to the primer. For reference, people have issues igniting primers if they have excessive headspace.

    Maybe I will have to try a test of my own with a known load I have, going from zero crush to bottoming out the cup.
     
    I also wonder what effect, if any, brass headspace has? If your virgin or sized brass isn't within +/- 0.0005" headspace, that would introduce another variable as the firing pin will be moving the cartridge in the chamber more or less before the energy is transmitted to the primer. For reference, people have issues igniting primers if they have excessive headspace.

    Very good question.
     
    I was hoping the author was going to explore more crush. Hell, isn't -0.002" in this case essentially zero crush? " In this case, I uniformed them to -0.1215". I then took the primers themselves and measured those to be exactly 0.119" from the bottom of the cup to the top of the anvil itself by using the Accuracy one primer depth gauge. "

    Yes it is zero crush. His best result came from the primer not even touching the bottom of the primer pocket. That’s not mechanically sound.
     
    I have a CPS and much prefer it to any other method I've used for priming. But I was surprised by the test matrix and how limited the seating depth was changed. Maybe it's just me, but I'm seating way deeper than 0.000 - 0.002" below flush with SRP brass. I used to use the priming feature of the Forster Co-Ax, which would yield a -0.007" depth with CCI450s and 6.5x47L Lapua brass (untouched primer pocket). So I target a similar depth with the CPS and haven't had any issues.

    I was hoping the author was going to explore more crush. Hell, isn't -0.002" in this case essentially zero crush? " In this case, I uniformed them to -0.1215". I then took the primers themselves and measured those to be exactly 0.119" from the bottom of the cup to the top of the anvil itself by using the Accuracy one primer depth gauge. "

    I also wonder what effect, if any, brass headspace has? If your virgin or sized brass isn't within +/- 0.0005" headspace, that would introduce another variable as the firing pin will be moving the cartridge in the chamber more or less before the energy is transmitted to the primer. For reference, people have issues igniting primers if they have excessive headspace.

    Maybe I will have to try a test of my own with a known load I have, going from zero crush to bottoming out the cup.
    Yes you're correct that it's a very small swath of available primer seating depths with most components. However, remember that the anvil sticks up WAY less with federal primers than CCI... so that won't always be true. I think the article did well in pointing out that this was just an introduction to the principle, but the actual testing should be performed by each individual. He spent at least a paragraph explaining that it wasn't going to be the "end-all be-all" end of the discussion, but rather the beginning of it.

    I can tell you from my own experience that a full primer seating depth test from anvil contact to just past complete crush, will most definitely reveal nodes much in the same way that bullet seating depth will. These results are shooter, equipment, and component driven... and therefor any hardened statements of actual "correct" primer seating depth will be misinterpreted as globally correct, rather than correct revealed as a result of testing. Much like the bullet seating depth of 10 thousandths off the lands, where everyone starts today... so too should full anvil contact and then proceed deeper be the beginning of the primer depth discussion.

    The article shows just how small an adjustment can have a significant impact on results. Its a start, not an end. That should suffice for those just now being introduced to the idea. Conversely, for those looking to pursue it further, a full primer seating depth test on your own is the only way to proceed. ... and you can forget seating by "feel" to accomplish this... because the variance from hand primed by feel will typically result in +/- .003 or more, while you can achieve +/- .0005 quite easily with a CPS, with many reporting better. Whether people can shoot the difference is a very individual answer.
     
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    I'm saving this article to read.

    I'm kind of like @morganlamprecht, I'm lazy with my reloading practices, still seem to get great results. The more I learn and reload, the more I realize what I can get away with. If I can turn 12 steps into 6 steps in the reloading room, while still having similar results, then I'm all for it. I do not uniform or deburr primer pockets, hell, I don't even clean them. This doesn't discount the article or its findings by any means, I'm sure there is some validity to it. To easily control primer seating depth certainly isn't a bad thing, I would love to have that capability.

    The CPS is one of the few tools that I actually really want for my reloading room that I don't currently have. For any sort of volume loading, I really start to despise my K&M hand press. It gets old quickly. The CPS would make volume loading so much easier and comfortable, and having the ability to precisely set the primer depth certainly won't hurt anything. Perhaps one day I'll get a CPS and explore the seating depths, would be an interesting experiment that I would like to play around with on my own ammo.

    I can easily see myself getting a CPS to make the reloading process easier and more comfortable, a benefit of more precision would be excellent. That's an easy cost to justify, I just need to be employed again. However, you aren't going to see me invest money in primer pocket tools, tools to turn necks, really expensive presses that claim to add more precision.
     
    An ES/SD of 1/1 will not hold up and to imply otherwise is horse shit.

    Give us more data and you’ll sell more machines
    I don't think the point of the article is that the CPS machine will yield SD's of 1. The biggest benefits of the CPS are fast and consistent primer seating with no fatigue. Seating hundreds of primers in a half hour, all within +/- 0.001" depth (or better), and not feeling like your hand is going to fall off...those are the reasons why you should consider a CPS.

    You can do a primer depth test with a number of other hand primers and should be able to determine if there is an optimum seating depth. That's not something I've pursued yet with the CPS but it will be on my list of things to try this offseason.
     
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    When I’m being meticulous and want to make sure everything is the same (shoulder, neck tension, seating pressure) and use the proper tools to measure them, my 3-5 shot strings are very reflective of 10-20 shot strings.

    If you control all the variables tightly, the need for longer strings becomes less important.
    Lol, I have said this for yrs. No one else really knows what you did exactly to draw the conclusion.
     
    Funny how the worthless comments are coming from the guys who never study or share shit.
    You know spife, and not even remotely pointing a finger at you, but when self proclaimed experts give others phrases to coin, it was always going to be a matter of time before those same phrases were thrown back.
    Not enough data.
    Sample size too small.

    i could go on for awhile.
     
    Not even my article and I’m expected to entertain people that claim it’s about selling units? There is simply no rational way to deal with you.
    Right, yet here you are posting an article highlighting your product. You need to to learn to let some things pass. The only thing holding me back from buying a CPS is your attitude, it is that simple.
     
    Funny thing about that is I think the CPS is a good product and I may own one some day. Not that you’ll sell me one, as I obviously am not a compliant customer who doesn’t ask questions.

    Of note, I didn’t post in this thread at all until I saw your hilarious post about others being belligerent. That was a completely rational post. :rolleyes:
     
    CPS's are selling faster than we can keep up, no matter how many $$$ I throw at it. We'll be lucky to make the rest of the week without going out of stock. They likely won't last the week. The timing of this article is not even REMOTELY in my best interest as we'll likely be out of stock for at least a month and so will our international distributor unless I can make some magic happen. I did not need nor did I want this article to move more CPS's right now. It may no doubt will sell a few in the long run, but not anywhere near as many as customers that have already received them are. Word of mouth, that's how these are moving. So the concept that I post this for my benefit is laughable. It is at this moment, directly opposed to my interests.

    The expectation you guys put on me to just ignore people that are engaged in dismissal of the truth is not an expectation I can or want to live up to. Especially when it's painfully obvious that the detractors have no testing of their own to report. Were you to walk up to someone in public and give them the treatment that many of you provide here when someone shares their work... I honestly do not think you'd have the expectation they would react well. Every single new idea or product gets treated exactly the same way by a sea of inexperienced and ignorant people. Yet it's just considered acceptable and expected that no one is allowed to speak up against irrational people on the internet being baseless detractors. Well, too bad. The concept that everyone's opinion matters equally is totally false.

    Many of us have known about the benefits of primer seating depth testing for quite some time. Hardly ever do I see it talked about. This article is one of the first pieces of work I've seen on it outside of my own, and I felt it important for people to see, as it can greatly help their reloading efforts. So go ahead and twist it all around. Dogpile. Attack the truth because you weren't convinced by someone's article. Attack me because you don't like me to begin with, then attack me further because I don't just sit in silence while people are laying their witty quips on me or the author of the work to get their stockpile of internet cool points. I literally have no interest in dealing with people that are so unreasonable as to read the article and only have negative things to say about it, complaining about what isn't there. I talked with Blake about offering more data points and shooting more... know what he told me? "I've done that before... it takes a long time, and no matter how much time I spend, people just behave the same way."

    He's right too. I've seen people type up 10 pages worth of data driven conclusions with all the proof required. Literally no place left to go, no stone left un-turned. On the forum thread you'll see super intelligent remarks such as "that's bullshit." The stronger your argument, the more people will resist it. So feel free to justify the detraction's in any way you see fit. Let your hatred of me cloud your judgement if you see fit. It won't change the truth of things. I won't be reasonable with people that are behaving unreasonably.

    UkDFivih.png
     
    I've said this before, but the CPS is one of those products that would be worth double the price just for the experience. I have no idea if the difference ever shows up on the target, although I know it would be years before I can shoot well enough to tell, but it doesn't matter. It's still worth it both because of superior ergonomics and the experience of using something so finely crafted.

    As for the article: it's a great concept to explore. Unfortunately, statistics are cruel and unforgiving, and I agree that no valid conclusions can be drawn from the data presented. I don't think anyone needs to get angry about this. It's difficult, expensive and time consuming to conduct valid experiments. Would it be nice if the author had done this? Yes. Is it OK for him to put out his point of view without adequate data? Of course.
     
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    Lol, I don’t hate you, but you believe what you will. Your points just above are valid, but look at the tags on your name and everyone else’s in this forum. One says “Belligerent”. That’s called a clue.

    I applaud that you are standing up for every vendor (as if) that, “gets treated exactly the same way by a sea of inexperienced and ignorant people.” However, somehow other vendors here seem to do just fine by treating potential customers less like “ignorant people” and more like potential customers that are trying to sort out the wheat from the chaff.

    As you yourself point out, the internet is full of people posting things all day every day. These include all kinds of claims and “experts” hawking the next best must have product. As a result, those that see new things or claims that maybe don’t fit a pattern they know will look for more information to back up those claims.

    It has been thoroughly discussed here that Standard Deviation (SD) is not valid without enough data points. The info presented in the OP used 3 (three) data points to gather SD. That understandably raised eyebrows. If you saw a new-ish product that used three data points to establish SD and you knew nothing else about it, I have to believe that you too would ask questions.

    However, as @Dthomas3523 pointed out, when one has an established set of data on a process that shows little to no variation and one knows that process to be in control, one can use fewer data points to garner an idea of where to make improvements. Ultimately, after transitioning to a new process, further collection of data is needed to verify that the new process or process improvements actually made a difference and are also in control.
     
    Lol, I don’t hate you, but you believe what you will. Your points just above are valid, but look at the tags on your name and everyone else’s in this forum. One says “Belligerent”. That’s called a clue.
    Uhhhh....
    1595517260788.png

    That's a tag the forum software uses when you have over 100 posts, I think.
     
    Lol, I don’t hate you, but you believe what you will. Your points just above are valid, but look at the tags on your name and everyone else’s in this forum. One says “Belligerent”. That’s called a clue.

    I applaud that you are standing up for every vendor (as if) that, “gets treated exactly the same way by a sea of inexperienced and ignorant people.” However, somehow other vendors here seem to do just fine by treating potential customers less like “ignorant people” and more like potential customers that are trying to sort out the wheat from the chaff.

    As you yourself point out, the internet is full of people posting things all day every day. These include all kinds of claims and “experts” hawking the next best must have product. As a result, those that see new things or claims that maybe don’t fit a pattern they know will look for more information to back up those claims.

    It has been thoroughly discussed here that Standard Deviation (SD) is not valid without enough data points. The info presented in the OP used 3 (three) data points to gather SD. That understandably raised eyebrows. If you saw a new-ish product that used three data points to establish SD and you knew nothing else about it, I have to believe that you too would ask questions.

    However, as @Dthomas3523 pointed out, when one has an established set of data on a process that shows little to no variation and one knows that process to be in control, one can use fewer data points to garner an idea of where to make improvements. Ultimately, after transitioning to a new process, further collection of data is needed to verify that the new process or process improvements actually made a difference and are also in control.
    Here's a crazy idea...

    People should do their own testing, and refrain from detracting until they have proof that THEY find acceptable, instead of expecting everyone else to do their work for them.
     
    LOL

    Seriously, how many customers do you just completely chase off, credit card and all, on your average month?
    You, milo, and lash, can be seen saying the same things in my threads... for roughly the past ten years. Your dedicated and continued concern for my welfare is uplifting. First comes the claim that I just want to sell things. Then comes the concern that I drive sales away.

    lol... every time. :ROFLMAO: Which is it? You take every opportunity to argue, belittle, and attack me... and then are all super shocked when I respond to you in a hostile manner. The internet, and the people on it... never cease to amaze me.
     
    You, milo, and lash, can be seen saying the same things in my threads... for roughly the past ten years. Your dedicated and continued concern for my welfare is uplifting. First comes the claim that I just want to sell things. Then comes the concern that I drive sales away.

    lol... every time. :ROFLMAO: Which is it? You take every opportunity to argue, belittle, and attack me... and then are all super shocked when I respond to you in a hostile manner. The internet, and the people on it... never cease to amaze me.

    I can't remember the last time I even bothered to look at, yet reply to anything you've posted. So let's not get too sure of ourselves here.

    I'm also pretty sure that has little to do with anyones concern about your welfare and more to do with the fact that you don't make it very difficult for people to not like you. The hilarious thing is, you're still the guy running into assholes all day amazed at the disproportionate amount of assholes that you seem to run into.

    You know how that saying goes, and shit, coming from me, that's something.

    I wasn't attacking you with my question. Instead, as a business owner, I was curious as to this phenemonea that you seem to have with how you deal with potential customers (even if you're actually right in what you're saying) and what I can only perceive as total ignorance on your behalf as to how this effects your business. From everything I've ever seen you do, you're more likely to have a hissy fit and respond to a question about one of your products with a long winded email about how the person used the incorrect font, emailed you during non business hours and must be too stupid to use your 'superior' shit because they had to ask a question about it. Shit, you should send a CV to H&K or something during the next time you take a hiatus from the site because people hurt you in the feels.

    I was just curious about if you ever comprehended this; and I'm by far not alone.

    Then again, what do I know? I retired in my early 30s, and you're going to be selling primer tools and shit until your 94.
     
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    You, milo, and lash, can be seen saying the same things in my threads... for roughly the past ten years. Your dedicated and continued concern for my welfare is uplifting. First comes the claim that I just want to sell things. Then comes the concern that I drive sales away.

    lol... every time. :ROFLMAO: Which is it? You take every opportunity to argue, belittle, and attack me... and then are all super shocked when I respond to you in a hostile manner. The internet, and the people on it... never cease to amaze me.
    Don't flatter yourself bud. I avoid your posts like the plague. I engaged to give spife some well needed grief. I just mentioned to you that quitting was an option, yet you continue to run your cockwasher.
    One theme that always surfaces in any post you are in, is that you end up telling people how ignorant they are, known fact. Your little tirades on LRH in the NF post was epic, and honestly, I was surprised how few members picked up on your arrogance. I do know why, the other idiot stole the show in that post.