Garmin Xero and Primer Sorting

[Rocketvapor]

Think I be done.
Nap time.

 

[RegionRat]

I'm curious what primer sorting would do for my load?

Just food for thought.... keep or pitch...

Maybe nothing, maybe important. Only way to know is to roll up your sleeves and check into it.

If you consider it important to keep the propellant charges trickled and weighed to a tenth of a grain or less, it is because you value the workmanship of the charge weights and their effect on velocity, and because it is easy to do so you might as well. Then....

If you consider that grain for grain, primer compound counts for more energy than propellant, and since primer weight changes are mostly due to primer compound variation, why would you allow that charge to vary.... unless you test that weight range to know the tune is tolerant?

High Master, or Rookie, at some point you may want to consider testing your tune for tolerance. That would mean to temp changes, powder, brass, bullet lot variations, .......and including primer weight variations.

At the very least, you may want to consider a QC inspection of a new lot of primers just to know they are running the same as the ones you tuned with. Otherwise, how would you know they are not the cause of a tune problem?

There are times when primer workmanship is better, and there are times when it is worse. Primers are made with human workmanship and it is more like kitchen science than folks think. YMMV

 

[Rocketvapor]

Here's a chart of Primer Weight Vs Velocity with test 2 and 3.

Legend: 31.8grains SB 6.5
Light: 15shots Avg 2996.9 ES 43.7 SD 12
Medium 15 shots Avg 3002.5 ES 37.2 SD 12
Heavy 15 shots Avg ES 33.8 SD 9.6

31.65grains SB 6.5
Strg 1 9 shots Avg 2975.6 ES 48 SD 16.7
Strg 2 9 shots Avg 2965.3 ES 22.4 SD 9.04
Strg 3 10 shots AVG 2963 ES 43.7 SD 14.3

 

[quest450]

I'm trying hard not to rain on your parade and you've done a ton of testing but I'm afraid that Salvage bolt gun and an AR15 may not be able to shoot the difference of all that stuff you're testing, maybe a proven bench gun capable of shooting 1/4 MOA build by a reputable smith might be a better option and I love testing and tunning as much as shooting
Good luck in your journey....it's a lot of fun

 

[Someone online]

Here's a chart of Primer Weight Vs Velocity with test 2 and 3.
View attachment 1541597

Hard to read the chart, details are blurry. Got a higher res version?

 

[Rocketvapor]

This 'Journey' is for fun.
Trying to improve with Kitchen built guns, in 22 Nosler, Handloading, Testing, Practice, Shooting together, Working on Midrange Master (soon I hope), is a challenge for sure. A 1/4 MOA gun built my someone that knows what they are doing would likely be a waste on us and take some of the fun out of it.
Maybe a wind tunnel would help

 

[Rocketvapor]

The velocity drop going down 1.5 grains of powder seems out of line.
More than expected.
Another 'anomaly' is the difference in primers, CCI450 and WIN41 in the
22N Savage (of course with sorted primers).
31.80gr 10 shot avg 2997.9, SD 14.0 with CCI 450
31.80gr 10 shot avg 3046.6, SD 15.1 with WIN41
Noticeable elevation difference @ 600yds
31.65gr 10 shot avg 2973.9, SD 14.1 with CCI 450
31.65gr 10 shot avg 3003.7, SD 12.4 with WIN 41
Not much elevation at 100 yds.
This is with her Savage @ 100yds.
Dialed back from 11MOA to Zero.
One shot to recheck Zero, then 10 with CCI then 10 with WIN primers.
Windage seems to be off by about 1 click (1/8 MOA)

 

[Someone online]

After reading this thread, I just weighed all 1000 primers in a box of CCI 250. Weighed from .329 to .344 grams. Majority were within .334 to .339. anything weighing beyond have about 200 weighing .340 and up, and about 100 weighing .333 and down.
I kept them all in separate trays of 100. One tray of .333 minus, trays of .334-.335, .336-.337, .338 to .339.
The next time I load these up, I will load some light ones, mediums, and heavies, and see if they all average different velocities, at least 30 in each weight.
Will also need to sort the cases by volume in each set.
Then measure the powder charge down to the same hundredth grain.
This rabbit hole is going to make this loading session take all weekend.

So I finished testing primer weight sorting as far as I’m concerned. I shot a total of 30 rounds each of Low primer weight, random primer weights, and high primer weights, over the course of 3 different range sessions.
The takeaway, sorting primers do have an effect. Low primer weights average lower velocity. High primer weights average higher velocity. Randoms had higher SDs.
I shot them in different orders between sessions.
Random, low, high
High, random, low
Low high random
They were all loaded the same day together in one go.
Cartridge was 6.5 prc and magpro powder.

Now I have about 2000 sorted primers, and will try to use primers from the same weight tray for each load.

 

[PatMiles]

Tagging in for future reference. Interesting reading!

 

[Someone online]

I should probably post what data I have. Actually shot 40 random primer weights and 30 each low and high weights total.
First session I had a new barrel and not broken in, I feel this set of data was less valid as a result. I shot 39 rounds total, in round robin. 1 low, 1 high, 1 random, repeat until all 39 was shot. Random had average 2965 fps,12.9 SD. Low average 2974fps, 9.5 SD. High average 2977 fps, 15.9 SD. Didn’t see the expected result. Again new barrel made this invalid probably.
Session 1 (barrel round count 0, about 60 degree weather)
Low 13 / 2974 / 9.5
High 13 / 2977 / 15.9
Random 13 / 2965 / 12.9

Session 2, shot 10 rounds random to warm barrel, average 2970 fps 12.7 SD. 5 shots low, 5 shots high, 5 shots random, another 5 shots low, high, random.

So session 2 data (barrel round count 150, 75 degree weather):
Random 10 / 2970 / 12.7

Low 5 / 3002 / 12.5
High 5 / 3021 / 8.9
Random 5 / 2993 / 11.5

Low 5 / 3002 / 10.2
High 5 / 3026 / 15.7
Random 5 / 3011 / 13.5

Combined data from session
Low 10 / 3001 / 11.9
High 10 / 3024 / 13.6
Random 20 / 2988 / 23.7
Random 10 (exclude first 10 barrel warmers) / 3005 / 18.5

Session 3 data in order (barrel round count 200, 65 degree weather)
High 7 / 3001 / 14 (very first shot was on a cleaned barrel, no fouling, had low velocity)
High 6 (exclude first shot) / 3005 / 4.9
Random 7 / 3008 / 17.5
Low 7 / 2993 / 8.1