Neck Tension and Seating Force

[NYDAN]

I had been loading some Hornady 130 gr. ELD-M bullets in my 6.5 CM and was getting significant marks on the bullet from the seating stem. So, I sent some bullets and cases to Forster Products with a request for a custom honed seating stem.

When they had finished the work (about one week), Scott from Forster called me to talk to me a little about neck tension and seating forces. It turns out Forster Products had been doing some research on this subject, and he wanted me to be aware of their findings. He sent me two links for my perusal. He said I could share them on the Nosler Reloading Forum so here they are:

TEST - this is a link to the test we (Forster Products) did on seating pressure.
PODCAST – this is podcast we (Forster Products) did where Josh (our pro-shooter) and I discuss a bit more in detail the test we did.

Since I have been using Forster Products, I have been very impressed with their customer service. For anyone who doesn't know, Forster Products will custom hone the neck diameter on their resizing dies to minimize under sizing the neck (avoiding over working the brass), and they will custom hone their seating stems for the bullet you are using so you don't get seating stem marks on your bullets.

 

[xphunter]

Cliff Notes Conclusions?

 

[300WSM]

That's good to know about forster but I have a question....

You are worried about a couple seating stem marks which isn't much but you're not concerned about the rifling grooves which is much more pronounced than seating stem marks.

I was just curious about that.

Perhaps a rhetorical question above and doesn't need answered....

I know one thing is for sure in our industry. If you think it makes a difference then you become a confident shooter. A confident shooter is more accurate all day long than a shooter who is not.

 

[Wolfshead]

This makes me want to look more into Forster products.
I’ve noticed some slight marks on my bullets after seating.
As is right now I’m not concerned as it is very slight.
As far as accuracy, I would like my rounds as accurate as possible, but neck tension is another variable that, for me, at this time I don’t want to be bothered with.
However a company that works with you on such things is very good!

 

[NYDAN]

Cliff Notes Conclusions?

"What We Found​

• Some bullets require significantly more pressure to seat properly, which can lead to impressions forming on the bullet
• Any case requiring over 125 lbs of seating force was more likely to leave a noticeable ring on the bullet.
• Reducing neck tension resulted in lower seating force across the board.
• The force required to remove a seated bullet was consistently higher than the force needed to seat it (by 16%–38%).
• Certain bullets inherently require more pressure to seat, regardless of neck tension.
• Using .001” neck tension kept all our test ammo under 100 lbs of seating force, with fairly consistent seating numbers.
  • However, when we tested an even lighter tension of .0005” (half a thousandth), the seating force became very inconsistent. Based on that experience, we wouldn’t recommend going that light.
    • This raises a concern when advising people to reduce neck tension. If you’re aiming for .001” but don’t have precise measuring tools or aren’t closely monitoring the results, it’s easy to unintentionally go even lower—closer to .0005”—which could lead to potential issues with consistency and bullet retention."

 

[NYDAN]

You are worried about a couple seating stem marks which isn't much but you're not concerned about the rifling grooves which is much more pronounced than seating stem marks.
I know one thing is for sure in our industry. If you think it makes a difference then you become a confident shooter. A confident shooter is more accurate all day long than a shooter who is not.

Every bullet fired from a rifle is going to have rifling marks. That is not something that the reloader can control. The seating stem marks are something that the reloader can control.

The Hornady 6.5mm, 130 gr. ELD-M bullets have a very soft (thin) jacket.

I sure as heck am not going to take a batch of loaded rounds that look like this to show off to JD338!

 

[sako2]

NYDAN looking at your pictures I see cooper shavings. Your bullets may not be starting straight. Try putting more chamfer in the case or switch to a vld chamfer tool. I load a lot of 140gn eld-m bullets in my 6.5 prc. https://www.amazon.com/RCBS-9351-VLD-Debur-Tool/dp/B000LC7LQ8

 

[xphunter]

Thanks @NYDAN !

 

[NYDAN]

NYDAN looking at your pictures I see cooper shavings. Your bullets may not be starting straight. Try putting more chamfer in the case or switch to a vld chamfer tool. I load a lot of 140gn eld-m bullets in my 6.5 prc. https://www.amazon.com/RCBS-9351-VLD-Debur-Tool/dp/B000LC7LQ8

Sako2, thank you for your comment. I have been meaning to order a VLD chamfer tool for some time, but I keep forgetting to add it my orders.

I can see what you see in the photos. However, it must be an anomaly of the photographs. I closely inspected the loaded bullets and could not see any shavings.

I used a concentricity gauge on those rounds, (and other rounds loaded with a different bullet) and when measured all the way out to bullets' ogive, the TIR was 0.002" or less.

The other bullets mentioned above are 130 gr. Sierra Tipped Game Kings. The seating stem made a very slight visible mark on the bullets but did NOT make any impression on them.

I just shot both loads this morning and both were 3/4" groups or less. However, the both the group and the velocities seemed more consistent with the Sierras.

I should receive the custom honed seating stem from Forster any day now. I hope to try it out with the next batch of loads.

 

[300WSM]

Every bullet fired from a rifle is going to have rifling marks. That is not something that the reloader can control. The seating stem marks are something that the reloader can control.

The Hornady 6.5mm, 130 gr. ELD-M bullets have a very soft (thin) jacket.

I sure as heck am not going to take a batch of loaded rounds that look like this to show off to JD338!

View attachment 26400

View attachment 26401

Pictures always tell more of the story.... your gouge marks aren't simple little seating stem marks.

I think you've got entry issues with those cases. Not enough chamfer or a trim that isn't square or both? Maybe something else but those marks aren't subtle and if that was a normal problem or common theme with that cartridge/bullet combo it would be pretty widespread across the inTRAnet.

Moreover I'd be curious to see what the back side of the bullet looks like where it sits in the neck.

 

[300WSM]

.I can see what you see in the photos. However, it must be an anomaly of the photographs. I closely inspected the loaded bullets and could not see any shavings.

Pull a bullet and take a look. Shavings can be pushed inside plus with that gouge I'd want to see what the back 1/3rd of the bullet looks like

 

[sako2]

Dan how many firings on the cases?

 

[NYDAN]

Those cases have been fired 3 times and annealed after both the second and the third firings.

 

[NYDAN]

I think you've got entry issues with those cases. Not enough chamfer or a trim that isn't square or both? Maybe something else but those marks aren't subtle and if that was a normal problem or common theme with that cartridge/bullet combo it would be pretty widespread across the inTRAnet.

I don't think there is a problem with the cases. The inside of the case mouths was chamfered both before and after tumbling. Three other types of bullets seat OK without denting the bullet. These bullets have very tapered boattails.

There is a reason I got a call from Forster and a reason they did the experiments that are reported above. In their lab, with their expertise, they had trouble seating the bullets, even with their customized honed seating stem, without leaving marks. It obviously wasn't the first time this has happened, and they had run the above-mentioned experiments to understand the problem better. Their conclusions indicate that I either need to reduce the neck tension or change bullets. I don't have a larger expander pin at this time and opted to change bullets. I will look into getting a larger expander pin provided, I want to go back to the ELD-M bullet.

The VLD chamfer mentioned by SAKO2 is a good idea which I have put off for too long.

 

[RL338]

I know that the older A-max were on the soft side , leaving a ring from the seater stem. I found that Bertram brass and Nosler CC don’t play well with each other.
How are you tumbling wet SS pins or dry vibrator? SS pins do leave the neck squeaky clean inside.
I do use honed Forster FL die for the 30-378 and several of their micro seater in multiple calibers , great dies.

 

[sako2]

I don't think there is a problem with the cases. The inside of the case mouths was chamfered both before and after tumbling. Three other types of bullets seat OK without denting the bullet. These bullets have very tapered boattails.

There is a reason I got a call from Forster and a reason they did the experiments that are reported above. In their lab, with their expertise, they had trouble seating the bullets, even with their customized honed seating stem, without leaving marks. It obviously wasn't the first time this has happened, and they had run the above-mentioned experiments to understand the problem better. Their conclusions indicate that I either need to reduce the neck tension or change bullets. I don't have a larger expander pin at this time and opted to change bullets. I will look into getting a larger expander pin provided, I want to go back to the ELD-M bullet.

The VLD chamfer mentioned by SAKO2 is a good idea which I have put off for too long.

I was thinking your brass was getting hard and needed annealing. Do you have a bushing die? I'm using a bushing die to resize and a hornady seating die.

 

[300WSM]

I don't think there is a problem with the cases. The inside of the case mouths was chamfered both before and after tumbling. Three other types of bullets seat OK without denting the bullet. These bullets have very tapered boattails.

There is a reason I got a call from Forster and a reason they did the experiments that are reported above. In their lab, with their expertise, they had trouble seating the bullets, even with their customized honed seating stem, without leaving marks. It obviously wasn't the first time this has happened, and they had run the above-mentioned experiments to understand the problem better. Their conclusions indicate that I either need to reduce the neck tension or change bullets. I don't have a larger expander pin at this time and opted to change bullets. I will look into getting a larger expander pin provided, I want to go back to the ELD-M bullet.

The VLD chamfer mentioned by SAKO2 is a good idea which I have put off for too long.

That's what I was referring to....


Bullet technology has come a long way but at a price. As in buying more stuff to properly use the new components. Not always but often times the new great thing brings a new can of worms.

If I missed it apologies but have you tried different mfg brass?

 

[NYDAN]

I was thinking your brass was getting hard and needed annealing. Do you have a bushing die? I'm using a bushing die to resize and a hornady seating die.

At this time I only have the Forster sizing and Forster micrometer seating dies. I may send the sizing die in to have the neck honed out so that it sizes the neck less, requiring less expansion.

 

[NYDAN]

I know that the older A-max were on the soft side , leaving a ring from the seater stem. I found that Bertram brass and Nosler CC don’t play well with each other.
How are you tumbling wet SS pins or dry vibrator? SS pins do leave the neck squeaky clean inside.
I do use honed Forster FL die for the 30-378 and several of their micro seater in multiple calibers , great dies.

I am using the wet tumbling with the SS pins. This batch of brass was my first time using it.

The brass that was wet tumbled with the SS pins definitely requires more force to seat the bullets than non-tumbled brass. I may change the order of my brass processing the next time. This time wet tumbling was the last step with a follow up inside neck chamfering to remove any neck peening. The next batch I may wet tumble after sizing but before neck expanding, trimming, and chamfering. Since I use graphite as an inside neck lubricant, expanding after tumbling may leave a bit of graphite lubricant in the neck. It will also insure there is no neck peening from the tumbling. It is all a learning process.

 

[JD338]

Dan,
The brass looks great. I size my brass and then wet tumble it. Then I check length and trim if necessary. Case mouths are always chamfered, regardless of trimming so bullets slide into the case neck.

JD338