Vertical Dispersion - Weighing Primers

[Rick300]

A medium to large pill container works great

 

[Rocketvapor]

OK, while I take a break from sorting some more
Was the horizontal E-Target some sort of calibration mode?
Seem to have seen that before

If you want to use grams, put a 1 (or 2, 3, 5) gram check weight on the scale.
Hopefully it will read 1.000. Put a primer on, weigh it 1point whatever grams.
Take the primer off, scale should read 1.000 again.
Rinse, repeat. Eliminates the half count (?) auto zero built into a lot of digital scales.
Full range scale error or linearity don't come into play.

My cheapo reads to 0.002 grams (counts by 2)
But reads to 0.005 carats (counts by 5), which is 0.001gram.
OK, back to sorting

 

[Ledd Slinger]

The GemPro250 has a readability of 0.001g. Note - that is readability, not precision, which is probably more like in the +/- 0.002g range (or worse). You're talking about using such a balance to sort primers by weight where the total weight variance for 100 primers might easily be less than 0.010g. A balance with 0.0001g readability would be a much better choice.

I dont weigh anything in grams so not sure exactly how fine a measurment that is off the top of my head. But the GemPro is the same resolution as the AND FX-120i that I had previously which is 0.02 grains. I use extruded powders like N570 and RL33 where a single kernel can weigh .04 to .06 of a grain so .02gr is a pretty fine resolution in my book.

The GemPro was checked against the FX120i many times for accuracy before I sold the FX and it always check out so I dont see why it wouldnt work.

I'll test it for myself and decide from there.

 

[Ledd Slinger]

And to take it step further here’s pretty good primer seater and a nice tool to measure primer pocket depth and primer seating depth.....yes I’m a control freak



View attachment 1162620

What is the ID opening measurement on that depth gauge and how much travel does the pin have?

That looks like it would also be perfect for measuring pin fall on Remington 700 style bolts if it can be set to travel far enough.

 

[Rocketvapor]

If you can find light and heavy primers, and repeat the measurement, you can sort out the outliers.
I've quit for the day. Filled up a tray with one weight. Now to label them
Using the check weight in the pan to check the scale and NOT let it go to zero shows you what is happening every time. While a GOOD check weight would be handy, all it NEEDS to be is the SAME/STABLE weight.

You really don't need to know grams, grains, carats. Just be able to find highs and lows.


The average APPEARS to be somewhere between
the 1.180 -01.185 group and the 1.190 - 1.195 group, and maybe just a tad closer to the 1.190 group. About 3.667 grains average??
With 7 outliers?? Gonna do any good on the range? Who knows

 

[quest450]

What is the ID opening measurement on that depth gauge and how much travel does the pin have?

That looks like it would also be perfect for measuring pin fall on Remington 700 style bolts if it can be set to travel far enough.

the ID is compatible with 300 Win Mag, .308 and .223 case or .532" max
and it looks like I have .130 of pin travel if I measured it correctly

 

[quest450]

 

[granite1]

OK, while I take a break from sorting some more
Was the horizontal E-Target some sort of calibration mode?
Seem to have seen that before

If you want to use grams, put a 1 (or 2, 3, 5) gram check weight on the scale.
Hopefully it will read 1.000. Put a primer on, weigh it 1point whatever grams.
Take the primer off, scale should read 1.000 again.
Rinse, repeat. Eliminates the half count (?) auto zero built into a lot of digital scales.
Full range scale error or linearity don't come into play.

My cheapo reads to 0.002 grams (counts by 2)
But reads to 0.005 carats (counts by 5), which is 0.001gram.
OK, back to sorting

I don’t know anything about “calibration modes”. I’m just debating with myself how much weighing primers might tighten this up. I know this was originally about vertical dispersion but it has me wondering. That and better gun handling.

 

[Rocketvapor]

I say,
If you got the time try it.
I've got enough sorted for 3 matches.
It is boring though

 

[Ledd Slinger]

..... it looks like I have .130 of pin travel if I measured it correctly

Dang it. Thank you for the info.

Looks like I'll just have to make a jig.

 

[mikeeg02]

You guys getting around 3.65 for an average with the 450's?
The boxes look like a better idea than trying to put them back in the trays.

My 450s range 3.62-3.76 grains.

My 205m's range from 3.62-3.72 grains.

Ive only ever opened one lot of each I guess. When I buy primers I buy them by the case. Same with powder, two 8# jugs at a time.

 

[Stingray]

Your doing well for the short time you've been shooting with us and remember you are shooting against some of the top FTR shooters in the country!

There is lots of good advice here but it's a non-linear progression from 300->600->1000 so for me a .36 MOA @ 300yd gun is not going to compete with the top shooters at 1K. Sorting primers may help but not that much. Remember what Tom said - MOST IMPORTANTLY, does it prefer the seating position and powder charge. If it's as good as it's going to get with N150 you may want to try a different powder/primer/.... If you tried others and it's still no good it could be that its just a decent mid-range barrel. I've got a few in that pile.

Also, measuring vertical at Bayou at 1K with a strong tail wind is a good way to drive yourself crazy. There were full 1-2 MOA vertical shifts out there last Sunday.

Reviewing the targets from Sunday with the tailwinds I would say that 1 to 2 MOA was the norm even for the better shooters. I find in my endeavors that vertical was best tempered by getting the seating dept right. If I get a load that will have an SD of 6 or less for 20 rounds and an MOA of .33 at 300 then I quit messing with it and load to shoot a match or to practice. Back to the original question when I have found the load my rifle likes I try three different primers to see what performs best. For me the test has to be 20 rounds to get a verifiable result.

 

[JFrank]

My 450s range 3.62-3.76 grains.

My 205m's range from 3.62-3.72 grains

Ive only ever opened one lot of each I guess. When I buy primers I buy them by the case. Same with powder, two 8# jugs at a time.

Just giving these BR primers a look I’m getting a high of 3.80 and a low of 3.69

 

[Rocketvapor]

I shot a few groups with BR4 and the 450's did a little better.
BUT,
I wasn't sorting primers.
Still have a few thousand BR4s. Might have to do another sort

 

[mikeeg02]

Just giving these BR primers a look I’m getting a high of 3.80 and a low of 3.69

My lot of BR4s goes from 3.68 grains to 3.80. I never shoot/use them lol

 

[Ledd Slinger]

Funny I dont see anyone reporting weights of Federal GM Match primers...

I have every single CCI made on hand for testing, SR and LR, but always seem to find more accurate loads with Federal. I havent weighed any primers yet, but curious if the Federal GM Match primers are more consistent in weight.

I will weigh them myself eventually, but am curious about others sorting them

 

[dkhunt14]

Add to that “bottomless pit” that if a barrel is particularly vulnerable to harmonic vibrations, (undamped, short or thin walled tenon, long, flexy stock/action) then just the throat erosion from each match could make the tuned load a truly moving target.

I shoot a lot of 300 WSM in my heavy gun. Throat erosion is almost non-existent. I get about .003 to .005 in about 1000 rounds. That is good, especially since I shoot 3 sighters in the last minute and then dump 10 records in 30 seconds. Also changes to load, due to temps and humidity doesnt seem to effect it much. Same load from April to October. Matt

 

[dkhunt14]

It's kind of funny, this is the 4th or 5th thread I've seen on weighing primers, but the first in which we've got a decent number of people admitting to doing it, and detailing the methods. Makes me think there's probably 10-15 lurkers for every poster doing this kind of thing too.

I have had some shooters call or PM me about weighing primers. Most were against it and then they asked questions. I told them to test it. Some were nice enough to return a PM with their results. Most of them were surprised and a couple said they would never tell the results because they needed an advantage. Instead of knocking the people that do it, why don't you just try it? Maybe your gun won't show it and maybe it will. The scales and gun must be accurate enough to show the difference. I also believe it shows up better at 1000 yards then at shorter distances. Matt

 

[dkhunt14]

Funny I dont see anyone reporting weights of Federal GM Match primers...

I have every single CCI made on hand for testing, SR and LR, but always seem to find more accurate loads with Federal. I havent weighed any primers yet, but curious if the Federal GM Match primers are more consistent in weight.

I will weigh them myself eventually, but am curious about others sorting them

Most use the CCI in their 6MM because of harder cups, the primer piercing thing. I use Federal in my WSM. I don't see much difference between match and regular in weight differences. I also see no difference in accuracy between the two. So, if I weigh my primers, it's like getting paid to do it, the difference in price between the regular and match. Matt

 

[dkhunt14]

Reviewing the targets from Sunday with the tailwinds I would say that 1 to 2 MOA was the norm even for the better shooters. I find in my endeavors that vertical was best tempered by getting the seating dept right. If I get a load that will have an SD of 6 or less for 20 rounds and an MOA of .33 at 300 then I quit messing with it and load to shoot a match or to practice. Back to the original question when I have found the load my rifle likes I try three different primers to see what performs best. For me the test has to be 20 rounds to get a verifiable result.

I like guys that don't test and believe in numbers. They are usually the ones that are easier to beat. Numbers don't always tell the truth. A good example is a chronograph ES verses actual target results.

Sometimes it is easy to color 5 bullets one color and 5 bullets another color, load them with the two different things and shoot them round robin in half decent conditions, sometimes the results are really easy to see and enough difference to see the difference. If still unsure, repeat the test again. Most times, what differences are clear enough to see, it repeats again. That way I save a lot of rounds on my barrel and can test a theory. Matt