Velocity vs Brass Weight Experiment.

[25WSM]

I have done some extensive testing on this myself. Since I shoot 1000 yard BR es/sd is very important to me. So a friend of mine that shot f-class and has a 20 ft long wall of first place and championship winning wood on it told me to shoot every brass and record the speed and sort your brass that way. He said weighing brass does absolutely nothing. I came to the same conclusion. I took the heaviest brass I found and the lightest and loaded them identical. Shot through my 35p and found that most of the brass at the extremes of weight varience shot within a few fps of each other. Also the load I used for these test shot es of 4 and SD of 10. Very consistent load so I know the load wasn't going to cause speed variables. So basically I found weight sorting to be nothing but a waste of time. I also took my velocity chart of 100 shots and weighed the brass from the slowest shots to the fastest and found the brass that produced those numbers were in the zone of the average weight of cases. I now only sort my brass by velocity once I find a low es load. I also did testing of primer weights. I found that the heaviest and lightest primers in a box of 100 produced speeds within the es of the load I was using. I don't weigh primers anymore either.
The problem with the ops test was he was using a load that he knew had a bad sd. That will really skew the results. I suggest you do the test again with a load that has low es numbers.
Or don't. I know from my test after velocity testing over 1000 pieces of brass that weight of brass does not correlate to velocity. These are my observations from test I've personally done myself and I'm a results driven reloader. To the op again. I've done multiple test on putting lubes inside necks on brass. I have found that the carbon from firing left in neck and just brushed produced the lowest es. I struggled for 2 months trying to get my guns to shoot when I started cleaning my brass with pins. I then shot some older brass that had not been cleaned and my accuracy was back. Results. No more cleaning my brass. Just a quick wipedown on the surface with a rag and done. Had to decide do I want to win or have shiney brass. Easy choice.
Shep

 

[AlphaDogs]

If you are a hunter (minute of Elk is 18"), buy Nosler prepped brass and avoid the agony.

 

[25WSM]

Not everybody wants minute of 18 inches. Most people on this site want the very best accuacy they can achieve. Not everyone is shooting elk. Long range hunting. Those shooting prairie dogs are hunting and wouldn't hit anything with minute of 18. The guys on here that shoot long range BR are a wealth of info for long range hunters. I load all my hunting rifle ammo to the same standards as my match rifles. So basically minute of 18 can be done at 1000 yards with a rifle shooting 1.5 inch groups at 100. I bet there is not on person on this site that would be happy with that in their long range hunting rifle.
Shep

 

[new2mud]

But MOE could be a newly minted accuracy term for the very-big game hunters only? "minute of elk"

 

[25WSM]

If Moe satisfies someone they should just go get a 299 dollar Walmart gun and a box of cheap factory ammo.
I'm just saying if you are hunting anything at long range you should be doing everything you can to achieve the best accuacy your rifle can achieve. With a Moe rifle you can't make any mistake of the distance to your target or miss the wind call by even 1mph. With a half moa rifle you have a much better chance for a perfect kill shot. Most rifles with proper loads will shoot 1/2 moa. Why settle for Moe when you can have mopd.
Shep

 

[Elk Hunter 338]

This is interesting..

question..... is this load in the middle between low and high node ??? seems light to me as most of my 7 mags run closer to 70-71 gr w/180 at high node ..

I've found sorting brass a pain and waste of my valuable shooting time

 

[entoptics]

...The problem with the ops test was he was using a load that he knew had a bad sd. That will really skew the results. I suggest you do the test again with a load that has low es numbers...

The ES/SD problem is pervasive, and not just this recipe. I've run half grain increments from 65.5 - 69.5 (pressure starts to show), running 3 shot groups, and revisited several areas a couple times or more, and no matter where the charge sits, I keep getting ugly fliers. I've used squeaky clean brass, graphite, and dirty brass, and it's happening with 2 different bullets.

ELD-X all results

I reload extensively for several other rifles, using the exact same procedures, and have no trouble achieving 20/10 ES/SD (usually a tad better).

The whole reason I tried this experiment, is because I wanted to eliminate a variable I hadn't addressed yet. As stated in the OP, I was mostly sure brass weight wasn't the problem, and my experiment confirmed that, so now I will move on to something else.

This rifle is shooting pretty good, consistently under MOA in the 66.5-67.5 range, and has printed a number of 0.5 - 0.75 MOA groups. For me, that is very good. Sure it's MOE out to 700 yds, but I plan to use it for ELR plinking, and the bad ES/SD is unacceptable for that.

Group Size Vs Charge Wt (some of the bigger groups in the lower charge weights were 400 yds on a breezy day). Groups went stringy (vert) and erratic above about 67.5, so I've abandoned that area for the most part.

 

[Quintus]

But MOE could be a newly minted accuracy term for the very-big game hunters only? "minute of elk"

Awesome for gunmakers. They could advertise and sell their wares as Range Certified MOE and have a laser engraved elk on the floor plate. I think you better trade mark it quick new2mud!

 

[PackersFanboy]

Remington brass 7mm rem mag krieger barrel 7828 h1000 4350 sd 5 180eld out 2000 yards. wet tumble brass, Anneal, bump, sinclair neck mandrel .002+- grain,
,

 

[new2mud]

If Moe satisfies someone they should just go get a 299 dollar Walmart gun and a box of cheap factory ammo.
I'm just saying if you are hunting anything at long range you should be doing everything you can to achieve the best accuacy your rifle can achieve. With a Moe rifle you can't make any mistake of the distance to your target or miss the wind call by even 1mph. With a half moa rifle you have a much better chance for a perfect kill shot. Most rifles with proper loads will shoot 1/2 moa. Why settle for Moe when you can have mopd.
Shep

I was being completely facetious.

Shep—I have deeply appreciated your dedication to the science and art of precision and learn a ton from you on this forum. Thank you for your contributions.

 

[Elk Hunter 338]

OP have you tried berger or sierra !!!

 

[25WSM]

New2mud I try to just get the info out so it might help someone save time and money. I don't personally shoot game at extended distance. My farthest kill was a deer at 525 yards. When I shot 100 and 200 br loading was easy. When I started 1000 yard BR I knew right away I needed to do things differently. Shooting a paper at 1000 is the same as shooting an animal at 1000. Only I get a big concrete table and a roof. Wind flags. A 17 lb gun or 77 lb gun. A nice stool to sit on and all the time in the world practically to break the shot. I would not want my gun to shoot any less accurate than it could for either. Shooting game at distance is way harder. But the loading methods should be the same.
Shep

 

[Shadowwalker]

But it is pretty easy to know where the weight is by measuring with tools every reloader should have, and also not knowing where the extra weight is- is a problem itself.

That is correct on centerfire and very time consuming. Impossible on rimfire.

 

[Mikecr]

Our notions of internal ballistics are often too simple and too far from realities to physically demonstrate.
This case weight -vs- any result is an example area, frequently debated and NEVER passing all tests.
At a higher level of consideration is case volume (H20 capacities). But variances here -vs- any result will not pass all tests either. I'll get to the reason later.

Begin with assumption #1, brass weight is meaningless to internal ballistics. Brass itself does not burn, and by the time it's area reduces chamber area(confinement), pretty much all of the pressure curve had already formed and functioned.
I could take 5 cases weighing the same, and with a few dies, a torch, and a hammer, I could shoot dots with it anywhere on your graph, high or low. This, even while the cases still weigh the same.
There are two things I'm changing there (while brass thickness is assumed normalized by weight): INITIAL VOLUME and CASE HARDNESS.
So much for brass weight...

You might wonder here WTH case hardness has to do with this. We're dealing with volume right? Confinement?
NO, not directly. And it won't pass all tests, as only a truth does.
You may have noticed over the years where folks have mentioned their MVs going UP with fire formed cases -vs- new cases. That seems odd,, fire formed cases hold higher volume, so their initial confinement is lower, so pressure should go down with them. Yet they consistently produce higher velocities.
So much for H20 capacities..

What were really dealing with here is: pressure peak energy given up to expand cases
The velocities produced with new cases are lower because some of the pressure peak is used to expand the new brass. To up-size it to chamber walls. Velocities are higher with cases that are fire formed and neck sized only, because they're already nearest chamber walls, with no further up-sizing occurring. So more pressure peak is pushing on the bullet. Softer or thinner brass expands easier, diverting less energy.

You might have noticed an occasional competitor seeing his best result with new cases. A sparse observation because -who competes or even pays attention with new brass?
But new brass, same lot, Lapua kind of stuff, is very consistent in both shape and hardness. It has not been munged up with all kinds of excess sizing and spring backs yet, so it's pretty consistent in chamber clearances. It will consume nearly the same energy to fire form those cases.
And given that most competitors FL size, new cases will bring them closer to a developed/proven load, than cases being sized so much to bring them back toward that.
Those who minimally size cases from fire formed, and develop loads there, will not see better results with new brass. But they could have low ES, at higher MVs, changing less over a higher number of reloads.

There is good or bad either way, depending on your planning, but my point is: forget brass weight, and volume, and strive to manage same chamber clearances with same case hardness -> to produce consistent pressure curves.
It may involve matching thickness and volume, but it's not the same thing.