6.5 Creedmor ejector mark question

[Lapua264]

Need some help to identify very faint ejector marks on new lapua brass.

The components are:
NEW lapua small primer brass
br4 primers
H4350
scenar L 136 gr
tikka t3x tac a1 rifle in 6.5 creedmor
COAL 2.860

Iam seeing very faint ejector marks at 42.7 gr which gives me around 2725 fps. The marks are only visible if i examine closely at certain angle, they are not raised or shiny. The primers look good, no cratering or flattening. Bolt lift is not stiff.

Can anyone advise if this is a pressure sign or something that happens to a new brass? Unfortunately i dont have lighter loads to compare. Cant get to the range anytime soon

thanks for the info!

 

[Stan Taylor]

Well I ask is this the very first firing on new brass.

 

[Lapua264]

Well I ask is this the very first firing on new brass.

yes it is

 

[243winxb]

Its a pressure sign. Hodgdon data with different bullets around the same weight does not use that much powder . Velocity is also lower, 24" barrel.

V V data for your bullet has a C.O.L. of 2.677 inch. If you loading into or close to the rifling, pressure will be higher. https://www.vihtavuori.com/reloading-data/rifle-reloading/?cartridge=95 There velocity matches yours. Different powders.

Factory ammo , in some cartridges, will have a light raised ejector mark like on the far right. The far left one is over pressure and the primer fell out.

Using you current loading may expand the primer pocket a tiny bit at each firing. If the primer becomes lose or fall out with 5 loading or less, pressure is to high, reduce load.

New brass that is not work hardened and has slop in the chamber may show the ejector mark.

 

[243winxb]

42.7 of H4350

Is this a compressed load? Needing a longer COL?

 

[Lapua264]

Is this a compressed load? Needing a longer COL?

Thanks for reply,
The ejector mark iam getting is even fainter than the one on the right. i literally have to look for it.
Unfortunately the tikka chamber is very long, it measured(hornady tool) 2.292 where ogive touches the rifling. I backed out .017 thou to sit the bullet @2.275 or COAL 2.860. Surprisingly, 42.7gr load was not fully compressed, some powder was moving around inside, probably because iam siting the bullet long. I was also confused because if it is a pressure sign, it appeared at velocities of low 2700s where VV is showing much less powder with compatible velocities. it is probably due to their COAL being so short, but i thought i can safely increase powder capacity by sitting the bullet longer....What am i missing here, really confused...

 

[243winxb]

With no other pressure signs, i think your loading is ok.

 

[Dusty Stevens]

Sometimes you get higher pressure with a reduced load and you were forming on top of that

 

[Ned Ludd]

The ejector mark correlates to an essentially unsupported region of the case head. Under 50,000+ psi pressure, the metal wants to move somewhere, and the unsupported region above the ejector is a likely place for it to go. This is why ejector marks can be such a difficult and unreliable indicator of actual pressure. You certainly don't want to ignore them if they're heavy, but light ejector marks may well be completely normal in your setup, especially if no other pressure signs are evident.

 

[Lapua264]

The ejector mark correlates to an essentially unsupported region of the case head. Under 50,000+ psi pressure, the metal wants to move somewhere, and the unsupported region above the ejector is a likely place for it to go. This is why ejector marks can be such a difficult and unreliable indicator of actual pressure. You certainly don't want to ignore them if they're heavy, but light ejector marks may well be completely normal in your setup, especially if no other pressure signs are evident.

Thanks for response.
Now If I load in increments and let’s say at 42 grains I don’t se the faint ejector mark and at 42.7 it begins to show, does that definitively mean it’s a pressure sign or also not necessarily?
And second, is it common to see pressure signs on the round that is not compressed?

 

[spife7980]

If you discover it as you progress up your charge weights then I wold say its a pressure sign. Carbon rings and virgin brass and high temps are all things that can make things over pressure when they wouldnt otherwise normally be.

It is common to see pressure signs on rounds that arent compressed if they are over pressure. Compression does not equal pressure. Powder burn rate, bullet weight, caliber etc all play into how much pressure is generated. A super slow powder in a small case may never go over pressure. A fast powder in a big case can go over way too quick.

As the bullet is fired the volume of the chamber behind the bullet grows as it travels down the barrel. A bigger bore means more volume a smaller barrel means less. A fast powder could fill that space up too quick, a slow powder could not fill it fast enough. A light bullet will move down the barrel quicker making more volume more quickly, a heavy bullet will move more slowly creating more volume more slowly. None of these things are linear and none of the relations ships between the variables is either and time plays an all important role.



6.5 creed 140 bullet is great with H4350. With H1000 the powder is a bit slow so it might not create enough energy fast enough to get you to a desireable velocity. With varget it is a bit faster than h4350 and you will create more pressure before you get up to velocity. Make that a lighter 120 gr bullet and the varget is a bit more well suited, the light bullet will move down the barrel faster which will more quickly make more space that the varget can fill. Maybe with the heavier 150 gr bullets H1000 would be more well suited, idk.


Stole this image off of a google search.
In the top graph youll see that its a win mag with a shotgun powder, it spikes right away to 50k and then drops off fast as the bullet travels down the bore but never gets it to over 2250 fps.
The bottom is the same set up with a magnum powder, notice that it gets to the same pressure but it does so gradually and over a much more sustained length of time and the bullet goesto 3100 fps. The more area under the curve you can get without going too high the better off youll be.

 

[Milo 2.0]

Pics always help, even if faint, we could view the primer too.
It's really hard to tell someone they are under pressured. I kind of think you are, new brass typically grows close to .005" in the base to shoulder region, I do not dare use the word headspace here, lol. So the brass is slammed into the bolt face, primers should be flatter on your first firing of new brass too. Under pressure loads can be hard on brass like stated above.
Here's a Quickload model of the info you gave, and I assume it is the 24" version of the gun. I reduced case capacity by a half grain.
If you plan on cutting your charge next outing, I would also load 2-3 at 43.5gr and fire them, if you get a stiff bolt, by all means stop, but give these the close inspection too.

 

[Ned Ludd]

Thanks for response.
Now If I load in increments and let’s say at 42 grains I don’t se the faint ejector mark and at 42.7 it begins to show, does that definitively mean it’s a pressure sign or also not necessarily?
And second, is it common to see pressure signs on the round that is not compressed?

As the pressure increases, of course it would be expected that the appearance of, and/or severity of, ejector marks would also increase. Whether that is a sign of dangerous overpressure is another question entirely. All I was trying to point out is that it's possible, if not common, to obtain visible faint ejector marks with loads that are entirely safe and not overpressure. For that reason, ejector marks alone can sometimes be a poor indicator that a load is overpressure.

The same thing is true of pressure signs based on the appearance of primers. There are a number of actions known for having rather large firing pins and/or firing pin openings. As with ejector marks, these represent unsupported areas for primer cups that are exposed to very high, even if safe, operating pressures. It is not at all uncommon for some primers fired in these types of actions to show evidence of pressure including cratering and/or piercing. However, these signs will disappearing when the firing pin hole is reduced using a bushing, or when a primer with a harder cup is utilized. Again, the point is that these type of "visible" pressure signs don't always mean overpressure. The key is to look at the bigger picture; i.e. is the load safe according to reloading manuals? Are there multiple different pressures signs at the same time? All of this information has to be considered in context before a reasonable conclusion can be reached. Having said that, I would also state that it is always better to be safe than sorry if you're not sure, which I'm sure is part of the reason you're asking these questions here. Over time you will likely develop a better feel for what some of these observations mean, but you're doing the right thing by asking questions.

 

[243winxb]

Quickload mode

What is pressure using V V C.O.L. of 2.677 inch.? Thank you.

 

[Milo 2.0]

What is pressure using V V C.O.L. of 2.677 inch.? Thank you.

He's going to have a tough time finding load data with the scenar anyway, unless it is VV data.

 

[Milo 2.0]

What is pressure using V V C.O.L. of 2.677 inch.? Thank you.

As expected, 2 tenths changes things big time, I shot enough of 6.5 creed to know the 2.677" is non realistic.
Here we go, I got ahead of myself, the velocity increase coincides with the pressure increase.

 

[Lapua264]

Pics always help, even if faint, we could view the primer too.
It's really hard to tell someone they are under pressured. I kind of think you are, new brass typically grows close to .005" in the base to shoulder region, I do not dare use the word headspace here, lol. So the brass is slammed into the bolt face, primers should be flatter on your first firing of new brass too. Under pressure loads can be hard on brass like stated above.
Here's a Quickload model of the info you gave, and I assume it is the 24" version of the gun. I reduced case capacity by a half grain.View attachment 1056753
If you plan on cutting your charge next outing, I would also load 2-3 at 43.5gr and fire them, if you get a stiff bolt, by all means stop, but give these the close inspection too.

Awesome, thanks for running the data. Can you clarify few things for me, never used quick load before. So the pressure that it displayed of 55k is well under presssure of 63k, does that mean that I can increase the charge with same coal, and the ejector marks I am seeing are not from pressure. apologize if it’s a stupid question. Also Does the program account for the jump of .017.
I will take couple of pictures of shot brass and post them in a few. Appreciate everyone’s input!

 

[Milo 2.0]

Awesome, thanks for running the data. Can you clarify few things for me, never used quick load before. So the pressure that it displayed of 55k is well under presssure of 63k, does that mean that I can increase the charge with same coal, and the ejector marks I am seeing are not from pressure. apologize if it’s a stupid question. Also Does the program account for the jump of .017.
I will take couple of pictures of shot brass and post them in a few. Appreciate everyone’s input!

QL cannot account for jump or freebore as per I know how to use it.
I need to clarify, I do not know, or cannot say you are not into pressure. I just do not Think you are. I'm not so sure if I was you, that I would follow my advice as far as adding powder.

Sometimes QL gets extremely close with a model, other times it's way off. But most of us do not have pressure trace equipment and make judgements based off experience. Proceed with caution.

 

[Lapua264]

QL cannot account for jump or freebore as per I know how to use it.
I need to clarify, I do not know, or cannot say you are not into pressure. I just do not Think you are. I'm not so sure if I was you, that I would follow my advice as far as adding powder.

Sometimes QL gets extremely close with a model, other times it's way off. But most of us do not have pressure trace equipment and make judgements based off experience. Proceed with caution.

This is 42.7gr, the faint ejector mark is over number 5

 

[Lapua264]

This is 42.7gr, the faint ejector mark is over number 5

This is 43.4 gr, the mark is between 6 and L, was getting 2775 with this load