Seating force variance

[JFASH]

I'm using a km arbor press (with a force pack) and my problem is brass segregation. I would like to know when you group by seating force, how many pounds do you deviate from in a group? 1 pound, 2 pounds?
Thanks
Joe

 

[JFrank]

I don’t use a force pack however I do have a thought.
Color the ones that vary 2 pounds than note any difference on paper,
Report Back”
Please

 

[JFASH]

I don’t use a force pack however I do have a thought.
Color the ones that vary 2 pounds than note any difference on paper,
Report Back”
Please

Ill try that spj

I don’t use a force pack however I do have a thought.
Color the ones that vary 2 pounds than note any difference on paper,
Report Back”
Please

My cases are annealed lapua brass and I'm getting (at the most) a spread of about +/- 6 pounds. Im going to test this out saturday. I'll report back. Thanks spj.
Joe

 

[JFrank]

Do you use a bronze brush on the inside of the necks or nylon.

I started making a pass or two with the Bronze followed by a clean up pass with the nylon, I’ve since noticed a difference in seating force.
(More consistent)

 

[JFASH]

Do you use a bronze brush on the inside of the necks or nylon.

I started making a pass or two with the Bronze followed by a clean up pass with the nylon, I’ve since noticed a difference in seating force.
(More consistent)

I've been using a nylon brush but the next time i reload the cases, I'll try a bronze brush. Ive tried this with annealed and unannealed cases. Are you annealing?
Thanks

 

[JFrank]

Nope

 

[JFASH]

Yes, i think im going to go the unannealed route next time.
Thanks

 

[JFrank]

No problem

Shoot Small
J

 

[JFASH]

Another question spj... do you clean your cases? If you do, are you wet tumbling or dry?
Thanks

 

[jds holler]

It is my sincere hope that a few pounds variance in neck tension will be of small consequence, considering the 50,000 + psi working pressure of a typical rifle cartridge. jd

 

[JFrank]

Nope
I just resize , clean out the primer pockets wipe um down brush the necks chamfer and load um.
Rarely have to even trim.

 

[JFASH]

Thanks spj

 

[JFrank]

It is my sincere hope that a few pounds variance in neck tension will be of small consequence, considering the 50,000 + psi working pressure of a typical rifle cartridge. jd

If Joe is willing to report back that’ll be great information

 

[JFASH]

I'll report back

 

[mikecr]

It is my sincere hope that a few pounds variance in neck tension will be of small consequence, considering the 50,000 + psi working pressure of a typical rifle cartridge.

Not a variance of neck tension, but of seating force.
Even if you normalized seating friction, and removed neck up-sizing(yielding) with seating, the remaining correlation with pushing force of a bullet to spring back gripping force, is not 1:1. There is leverage in play here.
We currently have no way to actually measure neck hoop tension, which is what grips a bullet, and is overcome on firing pressure to release it.

There is also the leverage in powder's burn timing character. With this, relatively slight confinement adjustments significantly affect pressure peaks.

 

[JFASH]

Not a variance of neck tension, but of seating force.
Even if you normalized seating friction, and removed neck up-sizing(yielding) with seating, the remaining correlation with pushing force of a bullet to spring back gripping force, is not 1:1. There is leverage in play here.
We currently have no way to actually measure neck hoop tension, which is what grips a bullet, and is overcome on firing pressure to release it.

There is also the leverage in powder's burn timing character. With this, relatively slight confinement adjustments significantly affect pressure peaks.

Do you group by seating force? If so, what would be the max/min poundage that you deviate from?
Joe

 

[mikeinct]

We did this before. Take say 25 loaded cartridges. All that have been nylon brushed after the mandrel expanding. You said you are seeing about 7 lbs of force variance. Divide them up in 4 lots, in 2 lb increments. one lot will be random one from each group. Set a target out with 4 bullseyes. minus -2lbs from the avg. then the random lot, standard, then the plus 2 lbs group. Take your time & don't mix up your shots. one or two into each bullseye until you have shot all 4 bullseyes. A couple of shots per at each target each rotation. Start at the first lot & bullseye again. 2 more shots per bullseye. in a round robin fashion. go slow it takes time to shoot thru this. However you run this 3 5 6 shots per target. then report back...Mike in Ct. PS watch the wind flags

 

[JFASH]

We did this before. Take say 25 loaded cartridges. All that have been nylon brushed after the mandrel expanding. You said you are seeing about 7 lbs of force variance. Divide them up in 4 lots, in 2 lb increments. one lot will be random one from each group. Set a target out with 4 bullseyes. minus -2lbs from the avg. then the random lot, standard, then the plus 2 lbs group. Take your time & don't mix up your shots. one or two into each bullseye until you have shot all 4 bullseyes. A couple of shots per at each target each rotation. Start at the first lot & bullseye again. 2 more shots per bullseye. in a round robin fashion. go slow it takes time to shoot thru this. However you run this 3 5 6 shots per target. then report back...Mike in Ct. PS watch the wind flags

I'll try that also.
Thanks
Joe

 

[JFrank]

We did this before. Take say 25 loaded cartridges. All that have been nylon brushed after the mandrel expanding. You said you are seeing about 7 lbs of force variance. Divide them up in 4 lots, in 2 lb increments. one lot will be random one from each group. Set a target out with 4 bullseyes. minus -2lbs from the avg. then the random lot, standard, then the plus 2 lbs group. Take your time & don't mix up your shots. one or two into each bullseye until you have shot all 4 bullseyes. A couple of shots per at each target each rotation. Start at the first lot & bullseye again. 2 more shots per bullseye. in a round robin fashion. go slow it takes time to shoot thru this. However you run this 3 5 6 shots per target. then report back...Mike in Ct

Uncle Mike
Your as OCD as the rest of us LOL
J

 

[mikeinct]

I should spend more time at the bench. You know instead of this friggin desk...Mike