Those who sort primers by weight...

[JFrank]

, sort your bullets, trim and point them and it might shrink your groups at 600 and 1K......

Stop talking crazy !!

 

[Robin Retzloff]

So, even with sorted primers, shouldnt the chrono numbers share similar numbers except the fps ?

Three rounds or six rounds cannot be compaired with each other or against each other. Too small a group. This was just to show elevation changes. What I saw in the group was stringing out, rather than circling, of the R hand group. Even then I would need at least ten shot groups to show anything I believed.

 

[misser]

Supposedly people have taken apart the pieces, cleaned everything thoroughly, and weighed statistically significant samples of all the metal bits on laboratory grade equipment. Allegedly they are disturbingly consistent, and therefore, any variation in the weight of an un-fired primer is either the compound, or for some brands/models, the sealant. If you search back through the forum you can probably find the original posts on the subject.

That your results seem to contradict that is somewhat surprising.

what about weighing spent primers ?? to fined the average of cup and anvil ?

 

[ShaunBrady]

It really doesn't matter what causes the changes in velocity with primer weight. If the velocity consistently changes with weight, that's enough for me. If that velocity change and the frequency it's likely to happen matter for what you're doing and it's worth 20 - 30 minutes per hundred to you, you'll do it. That's a pretty small slice of the hand loading community.

I was convinced from sorted vs unsorted in a large case that the effect was there. After a few of these threads, the merits of testing the outlier primers against each other in a small case became apparent.

For some of the ammo I load, I've decided it's worth it. I don't really feel the urge to chase causation badly enough to clean and weigh spent primer bits. I look at the manufacturing process and am pretty comfortable it's mostly the compound. If it turns out that extra cup and anvil reduce the primer pocket volume enough to intensify the effect of exactly the same amount of compound, it doesn't affect any of the other decisions I'm making, so I don't care.

With the guns I shoot, I doubt that I'd ever be able to pull the effects out of group sizes or statistics. The COF those guns are used on favor low velocity spreads so if I can reliably find it on the chrono, that's good enough for what I'm doing.

 

[kelbro]

View attachment 1737217
200 yd tunnel with 3.68g BR4 on the left vs 3.76 on the right. Next time I will do a 10 shot group. For some of us it is not busy work. It IS the fun. Shooting SWN is just a bonus.

Not sure why one of the primer weights would vary that much more than the other. That kind of goes against some of the recommendations that I've seen on here of 'just shoot the same weight together'.

Also, surprised that the heavier primer has the lower velocity.

And the numbering is interesting, did you rotate between the 3.68 and the 3.76 primers?

 

[ELR LVR]

what about weighing spent primers ?? to fined the average of cup and anvil ?

I have done so
Found no weight difference in my spent primers
(maybeeeeeeee once in awhile 1 primer would be .001 mg difference), that could be an air current

 

[Fire Dog]

Not sure why one of the primer weights would vary that much more than the other. That kind of goes against some of the recommendations that I've seen on here of 'just shoot the same weight together'.

Also, surprised that the heavier primer has the lower velocity.

And the numbering is interesting, did you rotate between the 3.68 and the 3.76 primers?

Also noting that the ES & SD is greater yet the accuracy is greater which seems to support the statements by others that ES & SD are not the Be All or End All when it comes to accuracy… Once again, the target tells…
Definitely needs a greater sample than three shots.
Ten would be a much better statistically valuable result.

 

[Robin Retzloff]

Not sure why one of the primer weights would vary that much more than the other. That kind of goes against some of the recommendations that I've seen on here of 'just shoot the same weight together'.

Also, surprised that the heavier primer has the lower velocity.

And the numbering is interesting, did you rotate between the 3.68 and the 3.76 primers?

I did rotate. Small groups of ES, SD, and velocity cannot be relied upon to make decisions. Today I shot 34 rounds of this same load with unsorted primers ES-17.5, ES-4.3. This was a tuner test that eventually lead to a nice round small 10 shot group. 10 round groups are the smallest I will make a decision on. 20 rounds are better. When I group primers my hope is to get rid of any outliers. The far ends of the primer weight range on a 1000 sorted BR4s are 3.66g and 3.80g, there were only a few of these. I shot these primers a few weeks ago at 600yds. It shows why I sort to remove the primers on the edges. These were not shot alternately, thus it shows the wind on the range.

 

[Pete Wass]

One thing that really makes a lot of this questionable is a Hummer Barrel. For those of us who have been fortunate to have one or more, A lot of the small stuff really doesn't matter. Unfortunately, they wear out.