Question about seating force ...

[rustyinbend]

Now that I have my AMP Press and can measure my seating force with great precision, I have a question for "The Collective". Is there a seating force target (in lbs of force at initial and/or peak) ... that any of you have found to be optimal? Or is it all about testing to find the force that's best for the particular barrel/bullet/charge/etc.?

Asked differently, for those of you shooting precision long-range that measure seating force, is there a "sweet spot" you've found that's consistently positive, or does it vary significantly and require different forces for different scenarios? Is there a "target" force that you try to start your testing? Just curious ...

 

[RegionRat]

It takes testing to determine what is sturdy enough for handling and magazine feed (or semi or full auto), and it also takes a balance between the prep and the load for precision and accuracy. So, you answered your own question well enough.

ETA: as for a sweet spot, the minimum I would use for a precision bolt rig is about 35 pounds for single feed. Some guys let the bolt closure seat the bullet.

 

[rustyinbend]

ETA: as for a sweet spot, the minimum I would use for a precision bolt rig is about 35 pounds for single feed. Some guys let the bolt closure seat the bullet.

Are you talking about 35 lbs Initial Force, Peak Force, or Terminal Force. My first attempt yesterday with 300-Norma cartridges ended up with averages of 34 (Initial), 80 (Peak), and 76 (Terminal).

 

[RegionRat]

Are you talking about 35 lbs Initial Force, Peak Force, or Terminal Force. My first attempt yesterday with 300-Norma cartridges ended up with averages of 34 (Initial), 80 (Peak), and 76 (Terminal).

Terminal. When the total bearing area is within the neck. Note that I am suggesting a minimum for prone match loads where I am not jamming and I single feed and the calibers are typically on the order of 30 to 22.

Your 76 terminal force value is typical. Like any load development, you will learn to collect baseline observations of what your process looks like, and watch for things like batch changes that change it, then test to verify it does or does not mess with your performance.

Details like case history, annealing, cleaning, chamfering, lube, and sizing, can all have an effect, as well as the bullet batch itself. The AMP Press is an excellent tool for observing the seating forces in detail, but that by itself doesn't determine what is "right or wrong".

 

[rustyinbend]

Terminal. When the total bearing area is within the neck. Note that I am suggesting a minimum for prone match loads where I am not jamming and I single feed and the calibers are typically on the order of 30 to 22.

Your 76 terminal force value is typical. Like any load development, you will learn to collect baseline observations of what your process looks like, and watch for things like batch changes that change it, then test to verify it does or does not mess with your performance.

Details like case history, annealing, cleaning, chamfering, lube, and sizing, can all have an effect, as well as the bullet batch itself. The AMP Press is an excellent tool for observing the seating forces in detail, but that by itself doesn't determine what is "right or wrong".

That's really helpful ... thanks. I agree ... the Terminal Force seemed a little high, just on intuition. I'm thinking I'll take my Mandrel from the .3075 I'm using to get the 76 Terminal, and grow it to .3080 and .3085 to see what it does to my curve, and do a .3085/.3080/.3075 test with all brass the same except for the mandrel size. I don't want to jam when seating, but I do want to test a lighter seating force and see what it does to SD's and groups. BTW ... this is 1x Lapua, Annealed (AMP), and sized on a Redding Type-S with a .333 bushing. I'm pretty damn meticulous about my process ... so things are usually really consistent. Sometimes consistent "good" ... sometimes consistent "bad" ... but consistent nonetheless, making testing a change pretty accurate.

 

[rustyinbend]

Terminal. When the total bearing area is within the neck. Note that I am suggesting a minimum for prone match loads where I am not jamming and I single feed and the calibers are typically on the order of 30 to 22.

Your 76 terminal force value is typical. Like any load development, you will learn to collect baseline observations of what your process looks like, and watch for things like batch changes that change it, then test to verify it does or does not mess with your performance.

Details like case history, annealing, cleaning, chamfering, lube, and sizing, can all have an effect, as well as the bullet batch itself. The AMP Press is an excellent tool for observing the seating forces in detail, but that by itself doesn't determine what is "right or wrong".

I had some time on my hands, and I was super curious what a larger mandrel would do for Terminal Force that we discussed above. I made three cartridges with a .3080 mandrel (1,2,3) ... and three with a .3085 mandrel (4,5,6).

The force above with the .3075 mandrel was 76-ish.
The force with .3080 averages 39.7.
The force with .3085 averages 20.1.

Obviously a small sample size, but still ... little doubt that simply adjusting the mandrel size without changing anything else, produces the lighter seating force I probably want. (Not a shock, but nice to see the data.)

Next steps ... (1) shoot the 23 I made with the .3075 mandrel and see how they perform. And (2) make a batch with the .3080 mandrel and see if the lighter seating force delivers any improvement in group size or SD.

 

[straightshooter1]

That's really helpful ... thanks. I agree ... the Terminal Force seemed a little high, just on intuition. I'm thinking I'll take my Mandrel from the .3075 I'm using to get the 76 Terminal, and grow it to .3080 and .3085 to see what it does to my curve, and do a .3085/.3080/.3075 test with all brass the same except for the mandrel size. I don't want to jam when seating, but I do want to test a lighter seating force and see what it does to SD's and groups. BTW ... this is 1x Lapua, Annealed (AMP), and sized on a Redding Type-S with a .333 bushing. I'm pretty damn meticulous about my process ... so things are usually really consistent. Sometimes consistent "good" ... sometimes consistent "bad" ... but consistent nonetheless, making testing a change pretty accurate.

Since there's an oxidation film left on the neck's surfaces after annealing that produces a lot of friction adding to the amount of seating resistance, I'm wondering what you're doing to mitigate that, if anything at all?

 

[rustyinbend]

Since there's an oxidation film left on the neck's surfaces after annealing that produces a lot of friction adding to the amount of seating resistance, I'm wondering what you're doing to mitigate that, if anything at all?

After annealing, I lube and size, and then I clean again (wet tumble). I've also started using NeoLube just prior to my mandrel step. That said ... this is the first I've ever heard about an "post-annealing-film" that's an annealing by-produce and needs to be considered ... and I've researched a lot about annealing. Can you point me to some additional data on this so I can read up on it? Thanks.

 

[spife7980]

After annealing, I lube and size, and then I clean again (wet tumble). I've also started using NeoLube just prior to my mandrel step. That said ... this is the first I've ever heard about an "post-annealing-film" that's an annealing by-produce and needs to be considered ... and I've researched a lot about annealing. Can you point me to some additional data on this so I can read up on it? Thanks.

The cooked on crust is why I always run a brush through my necks before I put a bullet in them.

 

[918v]

Are you talking about 35 lbs Initial Force, Peak Force, or Terminal Force. My first attempt yesterday with 300-Norma cartridges ended up with averages of 34 (Initial), 80 (Peak), and 76 (Terminal).

80 is way too much. I like 50 for bolt gun, 60-70 for semi-auto.

 

[918v]

After annealing, I lube and size, and then I clean again (wet tumble). I've also started using NeoLube just prior to my mandrel step. That said ... this is the first I've ever heard about an "post-annealing-film" that's an annealing by-produce and needs to be considered ... and I've researched a lot about annealing. Can you point me to some additional data on this so I can read up on it? Thanks.

It’s zinc oxide and is abrasive. It drives up seating pressure past 100PSI with .002” neck tension. You’re not going to find much on this because people are generally too inept to notice or over anneal the necks to the point where it doesn’t matter.

 

[straightshooter1]

After annealing, I lube and size, and then I clean again (wet tumble). I've also started using NeoLube just prior to my mandrel step. That said ... this is the first I've ever heard about an "post-annealing-film" that's an annealing by-produce and needs to be considered ... and I've researched a lot about annealing. Can you point me to some additional data on this so I can read up on it? Thanks.

Hmmm??? It's so obvious, I'm surprised you haven't really noticed that right after you've annealed your brass. It's also pretty easy to feel with your fingers. You've got the perfect machine to measure and quantify what difference there is before and after for your particular procedure.

Since you clean "again" after annealing, I take it you're cleaning your brass before you anneal them. How and how well one cleans their brass before annealing will effect what oxidation residue is left on the surface, where very clean brass will result in only a small amount oxidation film left behind. When you wet tumble after annealing, that film/residue is removed nicely. And of course, any lube used use in the neck for sizing a neck with a mandrel pretty much takes care of any "stickiness" the annealing produces.

BTW: This oxidation issue is not unique to annealing cartridge brass or any brass, as it's an issue for many metal alloys.

 

[smoooth1]

Mandrel Musings

When I first got my K&M arbor press for seating, I was somewhat surprised at the spread of the values of force required to seat bullets. Knowing that neck tension plays a significant role in ES/SD, I started doing various things to try to bring seating force in line. I had been doing most my...

www.snipershide.com

 

[rustyinbend]

It’s zinc oxide and is abrasive. It drives up seating pressure past 100PSI with .002” neck tension. You’re not going to find much on this because people are generally too inept to notice or over anneal the necks to the point where it doesn’t matter.

Not trying to be argumentative, but I'm struggling with a few parts of that.
1. You can easily drive up seating pressure just by shrinking the neck ... irrespective of any "residue".
2. Seating force is in "pounds" of pressure, not "pounds per square inch (PSI)". (I know, it's a nit, but details matter.)
3. Saying your perspective isn't well-documented because people are "too inept" is an odd way to back this up.
4. You infer that the oxide residue doesn't happen if you over-anneal ... that's interesting ... I need to ponder that one. Do you get a higher oxide residue if you "under-anneal"?
5. I use an AMP to anneal so the process is accurate and repeatable. I don't over-anneal ... at least I don't believe I do.
All that said, I'll continue to research and try to find something that documents this post-annealing oxide residue that you're describing.
Is it possible that it actually happens, but in a reloading application, is minor enough to not have a material impact on seating force?
Thanks!

 

[2aBaC̶a̶]

looks like were in need of an actual test to dispell these myths. if only somone had a precision machine that could measure seating force.

 

[rustyinbend]

looks like were in need of an actual test to dispell these myths. if only somone had a precision machine that could measure seating force.

HEY ... I know someone.
LOL
I got several tests loaded, and waiting for some range-worthy weather here in Central Oregon.

 

[918v]

Not trying to be argumentative, but I'm struggling with a few parts of that.
1. You can easily drive up seating pressure just by shrinking the neck ... irrespective of any "residue".
2. Seating force is in "pounds" of pressure, not "pounds per square inch (PSI)". (I know, it's a nit, but details matter.)
3. Saying your perspective isn't well-documented because people are "too inept" is an odd way to back this up.
4. You infer that the oxide residue doesn't happen if you over-anneal ... that's interesting ... I need to ponder that one. Do you get a higher oxide residue if you "under-anneal"?
5. I use an AMP to anneal so the process is accurate and repeatable. I don't over-anneal ... at least I don't believe I do.
All that said, I'll continue to research and try to find something that documents this post-annealing oxide residue that you're describing.
Is it possible that it actually happens, but in a reloading application, is minor enough to not have a material impact on seating force?
Thanks!

1. This is about zinc oxide increasing friction in the neck, not about neck tension. The seating pressure increases a lot due to the oxide.

2. I use a 21st Century Hydro Press with a PSI gauge. The force is measured in PSI.

3. That’s because you haven’t been in the internet reloading community very long.

4. The correct word is “imply.” I imply, you infer. In this case you inferred incorrectly. If you over anneal the zinc oxide is still present but the neck is so soft that it yields way too easily and the additional friction from the oxide does not matter anymore. But the case is shit and won’t shoot accurately.

5. I use an AMP as well. It’s accurate and repeatable only to the extent the user knows what he is doing.

 

[rustyinbend]

1. This is about zinc oxide increasing friction in the neck, not about neck tension. The seating pressure increases a lot due to the oxide.

2. I use a 21st Century Hydro Press with a PSI gauge. The force is measured in PSI.

3. That’s because you haven’t been in the internet reloading community very long.

4. The correct word is “imply.” I imply, you infer. In this case you inferred incorrectly. If you over anneal the zinc oxide is still present but the neck is so soft that it yields way too easily and the additional friction from the oxide does not matter anymore. But the case is shit and won’t shoot accurately.

5. I use an AMP as well. It’s accurate and repeatable only to the extent the user knows what he is doing.

Got it ... thanks. We can move on now. You win.

 

[Cascade Hemi]

1. This is about zinc oxide increasing friction in the neck, not about neck tension. The seating pressure increases a lot due to the oxide.

2. I use a 21st Century Hydro Press with a PSI gauge. The force is measured in PSI.

3. That’s because you haven’t been in the internet reloading community very long.

4. The correct word is “imply.” I imply, you infer. In this case you inferred incorrectly. If you over anneal the zinc oxide is still present but the neck is so soft that it yields way too easily and the additional friction from the oxide does not matter anymore. But the case is shit and won’t shoot accurately.

5. I use an AMP as well. It’s accurate and repeatable only to the extent the user knows what he is doing.

I would like to take a moment to recognize how crispy your pedantics are.

 

[Dogtown]

I would like to take a moment to recognize what a quality thread this is. It's the thing that brings me to SH daily, not the conspiracy theories and generally craziness.

 

[918v]

I would like to take a moment to recognize how crispy your pedantics are.

10 years ago they would have been a lot crispier.

 

[rustyinbend]

I would like to take a moment to recognize what a quality thread this is. It's the thing that brings me to SH daily, not the conspiracy theories and generally craziness.

Amen Brutha ... I enjoy it here too, but I tend to check-out when the flow of discussion degrades to incivility or insult. I just ain't got time for that.

 

[918v]

Amen Brutha ... I enjoy it here too, but I tend to check-out when the flow of discussion degrades to incivility or insult. I just ain't got time for that.

Yet you have time to correct people over:

“2. Seating force is in "pounds" of pressure, not "pounds per square inch (PSI)". (I know, it's a nit, but details matter.)”

Especially when you don’t know what you’re talking about.

 

[rustyinbend]

Yet you have time to correct people over:

“2. Seating force is in "pounds" of pressure, not "pounds per square inch (PSI)". (I know, it's a nit, but details matter.)”

Especially when you don’t know what you’re talking about.

I'm sorry, Rusty isn't available to continue this debate. Please try again tomorrow. (This is an automated response.)

 

[2aBaC̶a̶]

Yet you have time to correct people over:

“2. Seating force is in "pounds" of pressure, not "pounds per square inch (PSI)". (I know, it's a nit, but details matter.)”

Especially when you don’t know what you’re talking about.

 

[Cascade Hemi]

This thread delivers.