Vertical Dispersion - Weighing Primers

[mikeeg02]

Other than as a guess at a possible mechanism, I am not making any claims that the way in which weight-sorting primers improves precision in long range BR groups must be by affecting velocity. An effect on velocity would make sense, but that doesn't mean that must be the correct explanation. The only assertion I will make is that there must be some explanation for why it works. Whatever that explanation might be, there has to be one, even if we don't know what it is. I like knowing why things work in terms of accuracy/precision, for a lot of reasons. If sorting primers by weight improves groups, there has to be a reason why. If it's not velocity, it must be something else. If it's some property that has yet to be defined, or that is so subtle that the methods we typically use as analytical tools (such as velocity) are not capable of detecting it, so be it. It won't be the first time I've had to do something for which I simply had to accept that it worked, even if I couldn't explain why. Nonetheless, I feel certain there is such an explanation for why sorting primers by weight appears to improve precision, and I'd like to find out what it is if at all possible.

I agree with wanting to know why. And like Matt suggested above, we have some theories, but they are just that, theories. Most of us that experience these things spend a lot of time trying to figure out the why. Myself (and I know Matt and Donovan are the same way) try not to speak of things we dont fully understand. Or if we do, its as best as we understand it(not saying it never happens, but we try). Thats just the kind of people we are. We can tell you what we know it doesnt look like it affects, but to say we 100% are certain we know the why would be incorrect, therefore we are still working on that part, and dont want to make false misleading claims.

When you get a gun/load capable of shooting 4" or vertical or less at 1k, test it. See how many times you can repeat it. See what you have to do to maintain it. The point of all of this should not be to tell you whats right and wrong, its to give you ideas on things to test to the best of your abilities. A lot of BR guys have tested this, and given our experiences, its up to you to test and rationalize whether it works for you or not. Maybe you have hummer barrel and a load with a wide enough node you wont notice a difference. But if you do, I can just about guarantee you the next barrel will not act the same.

And one last time, I wish you would look at it as reducing the chance of flier. Not improving groups. While they sound the same, they are different. It doesnt fix a load, it helps to repeat/maintain it. You have to be able to read the target and the relay.

 

[Bindi2]

View attachment 1162608 When I read threads like this I get thinking I am skipping a step but then I remember this. I’m not knocking your efforts but this load in my rifle does this all time. Admittedly it’s not at 1,000 but it’s pretty flat.

If you have a tuner on your barrel it is not correctly tuned. The barrel is throwing side ways.

 

[Ned Ludd]

I agree with wanting to know why. And like Matt suggested above, we have some theories, but they are just that, theories. Most of us that experience these things spend a lot of time trying to figure out the why. Myself (and I know Matt and Donovan are the same way) try not to speak of things we dont fully understand. Or if we do, its as best as we understand it(not saying it never happens, but we try). Thats just the kind of people we are. We can tell you what we know it doesnt look like it affects, but to say we 100% are certain we know the why would be incorrect, therefore we are still working on that part, and dont want to make false misleading claims.

When you get a gun/load capable of shooting 4" or vertical or less at 1k, test it. See how many times you can repeat it. See what you have to do to maintain it. The point of all of this should not be to tell you whats right and wrong, its to give you ideas on things to test to the best of your abilities. A lot of BR guys have tested this, and given our experiences, its up to you to test and rationalize whether it works for you or not. Maybe you have hummer barrel and a load with a wide enough node you wont notice a difference. But if you do, I can just about guarantee you the next barrel will not act the same.

And one last time, I wish you would look at it as reducing the chance of flier. Not improving groups. While they sound the same, they are different. It doesnt fix a load, it helps to repeat/maintain it. You have to be able to read the target and the relay.

I most certainly appreciate your and Matt's responses. I also grasp the difference between eliminating a flier as opposed to improving overall group spread. Although there can be sometimes be a bit of overlap between the two in terms of the final readout, I agree that they are not the same thing. FWIW - I'm not a BR shooter. As an F-TR shooter, I'm not even particularly interested in weight-sorting my primers, because I don't view that as being the limiting source of error in the kind of shooting I do, and I doubt it would provide me with the same benefit for the investment of time. Nonetheless, as a scientist I find the concept intriguing and would simply like to better understand the mechanism by which it works. That's all, just a personal curiosity.

 

[granite1]

Sir, that's an outstanding target.

I have seen targets very similar to these (several instances actually) with electronic target frames that got the sensor hub wires crossed.

It might be worth investigating the target and/or the load/tune before your next big match.

Don't mean to derail the topic at hand.

I posted here simply to say that this subject got me thinking about the value of weighing not just to correct vertical but with my rifle and load, would it help me with horizontal spread. I posted the target to show what had occurred on one good day. There was nothing wrong with the target that day. I don’t use a tuner. And I think I am going to try weight sorting. What the heck, can’t hurt.

 

[MattPeetz]

View attachment 1162608 When I read threads like this I get thinking I am skipping a step but then I remember this. I’m not knocking your efforts but this load in my rifle does this all time. Admittedly it’s not at 1,000 but it’s pretty flat.

This is a classic crossed wires on the solo. Even if not, that is a horrible load. Would be horrible in the wind

 

[mikeeg02]

There was nothing wrong with the target that day.

Some of us have just seen that issue, and sometimes youll want to have a fresh paper backer to verify. When I first got my shot marker it was pretty windy. And I had the upper wires come around and inside of the lower sensors. (So they were properly connected, but the physical wire from the upper sensor had come between the lower sensor and the backer) My buddy thought he fixed the vertical on his 308. Everything looked like .200" of vertical at 500m, though not quite as much left and right as yours. We went down to look at the paper and that wasnt the case. Not saying thats your situation, but from past experiences, I would want a fresh backer every now and again so you can verify thats in fact whats going on. Since then I have screwed conduit clamps to the back to keep the wires from coming around the front at all. Remedied my issue.

Edit: Just to be clear, I am not doubting your target. I understand the struggles it takes to get a rifle to print a nice target, and have no reason to doubt you. I'm just offering my experience with that target so you hopefully dont run into the same issue I did.

 

[dmoran]

........ As an F-TR shooter, I'm not even particularly interested in weight-sorting my primers, because I don't view that as being the limiting source of error in the kind of shooting I do, and I doubt it would provide me with the same benefit for the investment of time.....

If scoring another 10 or two, or another X or two, isn't important to you, then definitely should invest your time else where.
But that is the kind of improvements F-TR / F-Class shooters could occasionally expect, from qualifying a poor Lot of primers.

You can argue the fact all you want and/or the reasoning's to why, but weight sorting/qualifying primers has repeatedly been proven by so many LR Benchrest shooters over so many years now, that it is an unarguable fact.

Sort to speak, if it can occasionally gain a 1000-BR shooter .2-MOA to a group, it can do the same for any discipline, and no matter what the accuracy level is, or how shrouded some test results may obscure the fact.

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[savageshooter86]

So I found my BR2 lot so far has had two at 5.10gr!!! The majority 5.20 to 5.26. And a decent number 5.28/5.32. And also had one 5.34. So 5.10 and 5.34 on a string might not be so good. That’s why I’m gonna test but I’ve already sorted mine

 

[tom]

Just for fun I did an experiment in the loading room, while sorting some 205s.

Here's a light full, and a heavy full, being dissolved of their compound with water. Hint, it speeds up the process to shake it.


Below is the dissolved primers drying.



The next couple below are their empty weights.





Sample size of 2, lol but it does appear about 66% of the weight you're sorting is compound. The heavy one is normally not a cull in my lot, but towards the heavy end. The light one was WAY OUT, and the photo below might explain where it came from.



This experiment is not indented to be scientific proof of anything, as I go about things by putting holes in paper for proof of anything I do or don't do.


Tom

 

[rsmithsr50]

tom,
where is the SEALANT weight in this "test " ?
cup
anvil
primer compound
sealant

 

[tom]

tom,
where is the SEALANT weight in this "test " ?
cup
anvil
primer compound
sealant

Visual inspection would say it's still attached. The only thing gone, best I could tell is the yellow compound itself.

Tom

 

[tom]

Cool test.....
Not often you will do a test that doesn't include putting holes in a target ... lol
A fairly significant variance in compound. Very interesting.
Thanks

Was on the phone with torgerson when I found that light one, and couldn't believe how light it was. It wasn't much out of my way to do it while continuing on my sorting. It's the first one outside of a tenth range in my lot...about the 1500th one weighed lol.

Tom

 

[Ledd Slinger]

I wish I had the time to do what @tom does...Lol

Hey Tom, can I bring these over and have you sort them all for me? That would be great...Thanks

 

[sqrlgtr]

OK My 2 cents.Thread was started back in 2011 and its 10 pages long and was just wondering if anyone has put up one of them voting polls to see what the results would be?I know weighing primers makes a difference for me but thought it would be interesting to see results of said poll.I would do it myself but afraid I would do it wrong lol..Maybe someone who is not so computer illiterate as me could do it....

 

[Rocketvapor]

Targets pics are enough.
Start a thread about seating bullets backwards and you'll get target pics

 

[MikeMcCasland]

OK My 2 cents.Thread was started back in 2011 and its 10 pages long and was just wondering if anyone has put up one of them voting polls to see what the results would be?I know weighing primers makes a difference for me but thought it would be interesting to see results of said poll.I would do it myself but afraid I would do it wrong lol..Maybe someone who is not so computer illiterate as me could do it....

This thread was started by me last week. I'm not taking credit for the participation by any means, but it's one of the first where we've actually had a productive discussion on the topic. I searched this topic pretty extensively prior to creating, and noticed that in past threads it's a few folks who will talk about their experiences, followed by folks shouting them down saying it's not worth the time investment etc.

The issue with primer weight testing is that it's not going to result in some massive difference, hence why it's a debated topic (i.e. if it were obvious, everyone would be doing it).

I certainly welcome more to chime in with their experiences, but there are 4-5 folks in here who are doing it, and they're basically saying the same thing. It won't drastically alter you group, but it'll keep things more consistent.

Again, I don't know that it helps, but it seems to me it can't hurt. I was just loading them straight out of the box before.

 

[sqrlgtr]

Targets pics are enough.
Start a thread about seating bullets backwards and you'll get target pics

Yeah I hear you,would make for some interesting results Im sure..

 

[tom]

I wish I had the time to do what @tom does...Lol

Hey Tom, can I bring these over and have you sort them all for me? That would be great...Thanks

View attachment 1163680

No, but I may hit you up for some 215s lol.


Tom

 

[mikeeg02]

I searched this pretty extensively prior to creating this, and noticed that in past threads it's a few folks who will talk about their experiences, followed by folks shouting them down saying it's not worth the time investment etc.

You'll find whats why most that do, wont bother to talk about it anymore. Its not worth the ridicule from those unwilling to learn or try. Its a little frustrating when someone will tell you that your information is invalid because you dont have enough data points, yet when you look at these people's aggregates, and year after year, they are still either on top or close in the hunt in 1k paper. Primer sorting isnt the only reason, but it is one of the steps.

 

[INTJ]

It's foreign to me to not try and do everything I can I shoot better. I promise that most of my fellow LR/BR competitors are doing everything that they can. I suspect many F-Class shooters have the same approach.

Weighing primers is fast and easy, so there really isn't a reason NOT to do it.

Long range shooting is significantly affected by conditions. Much of what we obsess over loading-wise only shows up in good conditions. Most of the time we are shooting in average and poor conditions. Thus most of the time, things like weighing primers don't make a difference. However, when we do get good conditions all that stuff can indeed make a difference.

Case in point. During the NBRSA 1000 yd regionals last October, on tuning day I shot three 3-shot groups that ranged from 1.5" to 1.875". I thought I was tuned and expected to do very well. However, for the match, my six target LG (5-shot groups) agg was 5.38" and my best group was 4.3". That was only good for third place.

I don't think I would have shot three consecutive sub 2" groups with a 6 BRA on tuning day--which obviously had very good conditions--without weighing primers. On the match days it likely wouldn't have made any difference.

So is it worth it to take a lot of time and effort doing things that will only help 10-20% of the time when conditions are good? For me, yes. It may not be worth it for others.