Vertical Dispersion - Weighing Primers

[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.

 

[skiutah02]

@MikeMcCasland, great set of questions. Primer sorting may be an option. Test sorted versus unsorted and see what happens.

Few other thoughts. Do you use a reliable chrono while testing? I ask as that would be a good way to determine if your ES is not as tight as it could be, which would point towards primer inconsistencies or your powder node being slightly off (for a 20 shot string an ES of 20 or less is ideal).

if your ES is tight, your challenge might be position related while firing, scope magnification/mirage issues, or seating depth issues.

If your ES is not ideal, you could examine your brass prep and/or do a simple test at LR.

Load up 3 rounds per charge weight, in .1 grain increments surrounding your current load. For example, if your current node was 50.3, then load 50.1, 50.2, 50.3, 50.4, 50.5. Shoot them round robin at 1,000 yards to see if any of them sing for you (keep same POA and measure vertical dispersion...don’t worry about horizontal).

From direct experience I can share that @dmoran helped me tremendously in identifying positive compensation at 1,000 yards by tweaking my node up or down by a single .1 grain charge. It works miracles to test this!

Let us know what you find.

^this

 

[Ledd Slinger]

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


Tom

Got any toilet paper and hand sanitizer to trade? Lol!

 

[Bc'z]

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.
View attachment 1163625

Below is the dissolved primers drying.

View attachment 1163628

The next couple below are their empty weights.

View attachment 1163631

View attachment 1163632

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.

View attachment 1163633

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

I stopped by Mark's house on way back from range and seen this lil yellow spot in a empty package of federal primers today. That's twice this week I've seen this.
No he dont weigh, and yes he was loading for this evening's local 600 match. Oops!!

 

[Ledd Slinger]

Havent sorted SRPs at all yet, but just got through testing 320 of my GM215M's in light of some upcoming load testing I will be doing with the new Berger 245gr EOLs in my 300 NMI.

There was plenty of outliers from a 0.1gr window but not bad. Lot of variation in the sealant. Some packed with it to the gill, a handful that didnt have any sealant, and others everywhere in between. Not sure how bad that effects the sorting, but I'm sure it doesn't help anything.

Considering a 0.1gr window and only 320 primers sorted, that's about 90% consistency so I'm happy with that. The last box sorted had a lot less outliers than the first 2 boxes and 1 partial box so not sure what the consistency would be if I kept going to the full 1K? Maybe I'll get time to continue. Very interesting to see how many fliers I've experienced in the past on paper possibly could have been cause by the extreme outliers.

For my testing purposes with the new Berger 245gr EOLs, I will only be using the center weight node of primers from 5.62gr to 5.66gr.

 

[Rocketvapor]

Total range +/- 2%.

+/- of less than 1% captures most of that sample.

 

[whatwind?]

I had very similar results, but went in 02 gr increments

also, my spent primers were 4.90-5.00


FEd 215m
lot 2GGI78

of course the last primer I weighed was the lowest, this was about 270 primers, didn’t have any huge outliers

 

[sqrlgtr]

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.

Mike,
My bad I must of looked at join date instead of date post was started duh and yes I have enjoyed this thread.Again I apologize Mike.I will restate I do believe you can see the results of this especially with certain lots of primers that have a big difference in weight,plus you and your equipment has to be up to the task also.

 

[Ledd Slinger]

I had very similar results, but went in 02 gr increments

also, my spent primers were 4.90-5.00


FEd 215m
lot 2GGI78

of course the last primer I weighed was the lowest, this was about 270 primers, didn’t have any huge outliers

The primers I weighed have been on the shelf for years now. I picked up a new 1000 lot of 215M the other day. Gonna weigh them to see if results are similar .

 

[Jennb]

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.

Mike the best thing you can do is test it yourself. Never take anyones word for what may or may not help you. Find out for yourself!!

 

[Ned Ludd]

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

Sample size of 2, lol but it does appear about 66% of the weight you're sorting is compound.

Tom

Tom - not sure I follow this. By my math, less than 10% of the total primer weight is priming compound (i.e. [weight after dissolving priming compound/weight before dissolving priming compound] x 100]. Are you referring to a percentage of total range of primer weights from high to low?

In any event, your experiment suggests another highly accurate approach to quantify the amount of priming compound in order to validate using a weight-based method. Specifically, anyone with access to a UV-Vis spectrophotometer could accurately compare the amount of priming compound using absorbance. Simply dissolve the priming compound for a few different weight-sorted primers in a specific volume of water, then measure the OD 410nm. By my spectrophotometric eye, the yellow color of dissolved priming compound in your plastic bottles will absorb very well at that wavelength. It's simply another way of directly and more accurately determining the concentration (i.e. amount per fixed volume of water) of priming compound, and one that doesn't depend on weighing anything before/after. Thus, it would be a good way to confirm or validate the use of a weight-based approach for estimating the amount of priming compound. Obviously, the primers tested this way would be lost, but it's simply a one-time experiment to compare with the results of weight-based sorting.

Mike - because you started this thread 20 days ago, I can only assume you are well along in the sorting process by now. My only advice is to pace yourself. The current "break from the ordinary" we are experiencing might last a while longer, so you probably don't want to sort all of them right away and then have to find something else to occupy your time.

 

[Rocketvapor]

I agree, pace yourself, but anyone that doesn't end up with sorted primers is just plain lazy
I've got peanut butter jars full of primed cases now but don't want to load them yet.

 

[dolek]

I agree, pace yourself, but anyone that doesn't end up with sorted primers is just plain lazy
I've got peanut butter jars full of primed cases now but don't want to load them yet.

Lazy?...or maybe smarter ?

 

[fyrewall]

Despite somewhat less than super precise weighing methods and showing results more precise than recorded, I still like the stuff in the attachment below because other factors or variables found in the loading process were eliminated. The primer blast waves were the only item measured and recorded.

https://arxiv.org/ftp/arxiv/papers/1102/1102.1644.pdf

Possibly, the group shapes or bullet holes are just vertically dispersed for reasons other than ammo characteristics - another variable.

 

[johara1]

Maybe it would boil down one thing .... sort everything ....... jim

 

[tom]

Tom - not sure I follow this.

I was looking at the difference between the two unmodified. Then the difference between the two with the compound dissolved. Since we are talking about sorting by weight, and a lot of times folks will ask what exactly of that weight difference is cup, anvil, compound....ect. So I just did this while I was working on the stuff one night. The difference was made 66% less different with the yellow stuff removed was how I saw it.


Tom