Reading tea leaves on target

[Pathfinder76]

I shot some loads over the chronograph yesterday with the intent of just getting some velocity numbers. But, I decided, at the last minute to throw them on paper despite a full value 30km/hr gusting cross wind. Here are the non scientific results. I had five runs of loads in 1/2 grain increments in both new cases and once fired cases. Interesting (though not totally unexpected) that the once fired cases produced consistently higher velocities.

[kujoseto]

Nice stuff.
I’m just about to run some reloder 16 loads for 165 gr in a 30-06 with 25” Jury barrel. This is encouraging to see.

I think a reasonable conclusion is when you get to testing with less wind, you’re gonna have something great for big game. Although, do you ever have less wind than that down there?

How did those velocities compared with where you expected them to be?
What’s the rifle?

[Pathfinder76]

The rifle is a custom Model 70.

Often fired cases will produce less velocity because of greater case capacity. I think in this case, capacity is similar but the fired cases have a bit more neck tension. That raises pressure a bit.

[kujoseto]

What do you use for sizing that makes the neck tension greater? What did you use for new brass load? How did the two differ?
Sounds like a nice rifle. Is that the one you have posted pictures of that has the brown synthetic (McMillan?) stock?

[Pathfinder76]

It is, yes.

Once fired brass is harder and has more spring back. Even with the same expander mandrel run through the neck, it had 10 thou more tension.

[Deer Hunter]

Originally Posted by chuck

It is, yes.

Once fired brass is harder and has more spring back. Even with the same expander mandrel run through the neck, it had 10 thou more tension.

10 thou more neck tension must make it hard to seat bullets.

[Pathfinder76]

Originally Posted by Deer Hunter

10 thou more neck tension must make it hard to seat bullets.

Sorry. one thou.

[Nyksta]

8, 9, 10, 11 if you find it repeats itself

[kujoseto]

Originally Posted by chuck

It is, yes.

Once fired brass is harder and has more spring back. Even with the same expander mandrel run through the neck, it had 10 thou more tension.

Ah, okay. I would say I’ve noticed that from time to time when loading some rounds but wasn’t certain as to why.
Sometimes I use rcbs FL, Lee collet, Redding bushing, or CH bushing dies. So far, I can’t say one is head and shoulders above the other.
Knew you meant 1 thou as well.

[Pathfinder76]

Originally Posted by Nyksta

8, 9, 10, 11 if you find it repeats itself

I think that’s where I’ll end up.

[Deer Hunter]

Originally Posted by chuck

Often fired cases will produce less velocity because of greater case capacity.

Does case capacity or chamber capacity determine the pressure/velocity?

[Pathfinder76]

It absolutely can, yes.

[no-regard]

Interesting test, thanks for posting. Neat to see the pattern in velocity increase as they all walk up the target, as well as the repeatable velocity change between the cases.

[Deer Hunter]

Originally Posted by chuck

It absolutely can, yes.

So your essentially saying new brass is smaller, has less case capacity therefore increases pressure and velocity compared to fireformed brass. That’s a new one for me.

[Pathfinder76]

Originally Posted by Deer Hunter

So your essentially saying new brass is smaller, has less case capacity therefore increases pressure and velocity compared to fireformed brass. That’s a new one for me.

It can be, yes. It Is the same reason two different manufacturers of brass can produce different velocity with the same charge weight of powder. It’s also why you enter water capacity of brass into your quickload program. Internal volume matters.

[Deer Hunter]

Originally Posted by chuck

It can be, yes. It Is the same reason two different manufacturers of brass can produce different velocity with the same charge weight of powder. It’s also why you enter water capacity of brass into your quickload program. Internal volume matters.

But the chamber is the same, the brass is the same.
Resized, or under sized brass that is all the same manufacture will have the same/similar internal volume when fired. Or in other words occupy the same space in the chamber when fired.

Different manufactures brass only matters wrt pressure and velocity because it may occupy more room in the chamber upon firing.

You don't enter the water capacity of new or sized brass into quickload. Fired brass capacity only matters as it relates to the chamber. That's what you enter.

[Deer Hunter]

Originally Posted by chuck

capacity is similar but the fired cases have a bit more neck tension. That raises pressure a bit.

1 thou increased neck tension is responsible for higher pressure and velocity? That's incredible.

[Nyksta]

Originally Posted by Deer Hunter

But the chamber is the same, the brass is the same.
Resized, or under sized brass that is all the same manufacture will have the same/similar internal volume when fired. Or in other words occupy the same space in the chamber when fired.

Different manufactures brass only matters wrt pressure and velocity because it may occupy more room in the chamber upon firing.

You don't enter the water capacity of new or sized brass into quickload. Fired brass capacity only matters as it relates to the chamber. That's what you enter.

Different brass will have different wall thickness and result in different internal volume. Another factor with fired brass vs new brass, is how perfect a match the brass is to the chamber. If the brass needs to expand more before a tight chamber seal is achieved, the pressure curve will be different. Smokeless powder burns faster as the pressure increases. A lower inital pressure has a slower burn rate. The brass fit to the chamber, and the internal volume will all be part of this.

[Pathfinder76]

Originally Posted by Deer Hunter

1 thou increased neck tension is responsible for higher pressure and velocity? That's incredible.

Quit trolling me and actually look at the velocity numbers in my post. Man this is getting real old.

[Deer Hunter]

Originally Posted by chuck

Quit trolling me and actually look at the velocity numbers in my post. Man this is getting real old.

I am not trolling you. I am discussing your findings. And reasoning. If you don't care to discuss it with me fine, but no need to take your ball and go home.

I have seen no velocity differences in varying neck tension. Crimps included.

[Deer Hunter]

Originally Posted by Nyksta

Different brass will have different wall thickness and result in different internal volume. Another factor with fired brass vs new brass, is how perfect a match the brass is to the chamber. If the brass needs to expand more before a tight chamber seal is achieved, the pressure curve will be different. Smokeless powder burns faster as the pressure increases. A lower inital pressure has a slower burn rate. The brass fit to the chamber, and the internal volume will all be part of this.

Sure, brass of different fired internal volume (different manufacturers) results in different chamber pressures.
But not the same brass sized differently in the same chamber. The sizing of the brass doesn't change the total occupied space in the fired chamber.

[sns2]

Deer Hunter, block Chuck. Chuck, block Deer Hunter. Problem solved. All of us are getting sick of this.

[Deer Hunter]

Originally Posted by sns2

Deer Hunter, block Chuck. Chuck, block Deer Hunter. Problem solved. All of us are getting sick of this.

I apologize if I'm making you sick discussing reloading experiences in the guns and ammo section of a outdoors forum. Chuck accuses trolling. I'm just trying to discuss. Sorry.

[Dean2]

Originally Posted by Deer Hunter

Sure, brass of different fired internal volume (different manufacturers) results in different chamber pressures.
But not the same brass sized differently in the same chamber. The sizing of the brass doesn't change the total occupied space in the fired chamber.

DH

I like both you and Chuck but in this case Chuck is right and you are therefore wrong. The sized capacity of the case definitely impacts pressure and velocity. Fireformed cases almost always show less velocity than new cases, if you hold the neck tension exactly the same. If you FL size a case it will show higher velocity than neck sizing the same case. Give it a try, you will find Chuck is right. I was actually surprised to see the once fired having consistently higher velocity in his test till he said the 1x fired had higher neck tension.

[Deer Hunter]

Originally Posted by Dean2

DH

I like both you and Chuck but in this case Chuck is right and you are therefore wrong. The sized capacity of the case definitely impacts pressure and velocity. Fireformed cases almost always show less velocity than new cases, if you hold the neck tension exactly the same. If you FL size a case it will show higher velocity than neck sizing the same case. Give it a try, you will find Chuck is right.

You might be right dean but this has not been my experience.

[kujoseto]

The experience of many here is congruent with Chuck’s. Increased neck tension holds that bullet for pressure to mount just enough to increase his velocity by 9-25fps in this case. No pun intended.
And you’re making arguments against the recorded data posted above for you to see. He stated the facts of the situation and it’s for you to interpret, but you can’t say that’s backwards when his data is sitting right there.
I do wonder if energy is lost at all reforming the case in the chamber. So new brass or re-sized smaller may make enough difference to shave 10 FPS but I don’t have enough experience to know.

[kujoseto]

Originally Posted by sns2

Deer Hunter, block Chuck. Chuck, block Deer Hunter. Problem solved. All of us are getting sick of this.

Where’s the like button?
As soon as Deer Hunter (and a couple others) show up where Chuck and elkhunter11 are commenting, it’s the same thing every thread.

[crazy_davey]

Originally Posted by kujoseto

As soon as Deer Hunter (and a couple others) show up where Chuck and elkhunter11 are commenting, it’s the same thing every thread.

Bingo!

[DLab]

I'll have to go with Chuck on this one.
BUT WAIT!.... HOLD ON JUST A SECOND BOYS!!!....I can settle these Threads...
I found a Ruler....and it's in Metric! Every one will be happy!

Thought a little brevity was needed.

[kujoseto]

Originally Posted by DLab

I'll have to go with Chuck on this one.
BUT WAIT!.... HOLD ON JUST A SECOND BOYS!!!....I can settle these Threads...
I found a Ruler....and it's in Metric! Every one will be happy!

Thought a little brevity was needed.

Hahaha