Correlating seating force with... anything?

[Bart B.]

Which situation is most critical in achieving uniform muzzle velocity, pressure curves or whatever regarding bullet and case neck diameters?

Diameter difference between die neck and loaded round neck, commonly called tension.

Interference fit; the diameter difference between bullet and the resized case neck inside diameter.

Bullet's seating force, when reloading, in pounds.

Bullet's pull or extraction force, when fired, in pounds.

 

[Richard Coody]

whatever works for you but this is what i have found

i use the 21st century shooting hydro press. now on my 6br bench gun i use very light neck tension. .001 or less. i use the gauge reading to confirm the consistency of my annealing, sizing and neck prep procedure. For me everything in precision shooting boils down to consistency. i have found that you can see a difference on the target. now this is at a 100 yards and we are talking about groups in the 1's and 2's. if i sort by seating force the ones 20 and under and 40 and above produce larger groups and are less consistent then those between 30 and 40. Nothing scientific about it. just my observations.

now on regular ammo with .002 or more neck tension consistency of seating force just goes out the window. A waste of time. in fact i don't use my force gauge for that. it puts too much pressure on the gauge.

 

[Bart B.]

if i sort by seating force the ones 20 and under and 40 and above produce larger groups and are less consistent then those between 30 and 40.

Those numbers are pounds of force? Or ounces.

 

[Richard Coody]

Those numbers are pounds of force? Or ounces.

i really couldn't tell you. it really doesn't matter to me. it is consistency i am looking for.

 

[Bart B.]

I asked because military specs on small arms rifle ammo list a minimum bullet extraction force in pounds. 60 pounds for ball ammo, 20 for 7.62 match and sniper ammo.

Little force is needed to seat their bullets. Case necks are upsized about .002" larger than bullet diameter creating a small donut inside, then smeared with sealant before bullets are seated. Match and sniper ammo is not crimped, all others are.

 

[Richard Coody]

I asked because military specs on small arms ammo list a minimum bullet extraction force in pounds. 60 pounds for ball ammo, 20 for 7.62 match and sniper ammo.

i believe the military has much different priorities then i do with my 6br bench gun.

i do notice the have lighter neck tension on their match and sniper ammo. wonder if they can get in the 1's with it?

 

[foxguy]

I'm not Jim, but thought I'd jump in here because of the title of your post...Correlating seating force with...anything." I use a Sinclair Arbor press (w/Wilson seaters for all my calibers) that doesn't have any measuring instrument that tells me how much pressure I'm exerting to seat a bullet. Rather, that "feel" of the action of seating tells me a good deal about the status of my Lapua (Norma or LC brass) and it's neck tension. I specifically look for uniformity in the seating process and can actually tell when one piece of brass is either too soft or too hard, possibly due to aging or some other factor, like that piece needs annealing. But I'm curious that you appear concerned about when you seater bottoms out. It strikes me that when I can't pull on the lever anymore, she's hit bottom and a visual look confirms the feeling of having hit bottom. I then measure the ojive on each seated casing to verify the proper seating depth of the bullet.

I use the .002 neck tension and also Imperial Dry lube by dipping each casing neck into the dry lube and shaking off the excess before seating the bullet. This process has proven successful for me and it shows on my targets downrange. BTW, I've tested this by separating out the harder seating bullets which aren't hitting or grouping as accurately as the consistent feeling seated bullets. The softer seated one don't seem to make a difference. Probably not very scientific, but it works for me. Info only.

Alex

Just a Question on the Imperial Dry Lube, So if I understand this correctly you are dipping the case neck into the dry lube, shaking it off, charging the case and then seating the bullet. If you detect abnormal resistance in seating the bullet you set that round to the side for fouler/sighter round?

Thanks,

 

[Bart B.]

i do notice the have lighter neck tension on their match and sniper ammo. wonder if they can get in the 1's with it?

Back in their day, 7.62 M118 match ammo bullets were pulled then replaced with 168 or 180 grain Sierra match bullets. Powder replaced with IMR4320 then 190's seated for use in Garands. I've done hundreds myself. A few days or weeks later, they needed about 3 to 7 pounds of pull force to extract them.

In the best match grade M14 and M1 rifles, they tested about 4 inches at 600 yards. That equates to shooting in the 2's and 3's at 100 yards.

Worst component in all USA arsenal components for 30-06 and 7.62 match ammo was that 173-grain FMJBT bullet. Each lot of match ammo had bullets from 3 or 4 sets of dies. Their quality ranged from fair to poor. Best 250+ round test groups at 600 yards was about 10 inches (1.9" mean radius). Specs were about 18 inches (3.5" mean radius).

 

[Richard Coody]

Just a Question on the Imperial Dry Lube, So if I understand this correctly you are dipping the case neck into the dry lube, shaking it off, charging the case and then seating the bullet. If you detect abnormal resistance in seating the bullet you set that round to the side for fouler/sighter round?

Thanks,

i too have tested the imperial dry neck lube. i dipped the base of the bullet into it before seating. i would reccomended that procedure for new cases or those who have been wet cleaned but i have found that leaving the carbon in the necks with just a light brushing with a nylon brush works best for me

 

[davecb]

I load my 6.5x47 with .002" neck tension. I very rarely get a force reading at all when I seat my bullets. I was told to "exercise" the ram before using it. I can do that and watch the gauge move normally. However, when I seat my rounds(140VLDs) I get no gauge reading whatsoever. The rounds seem to hold in the case fine though. Would it be better to use a tighter bushing so I get some sort of reading? Apparently as of now, they are all under 2lbs seating force.
If it matters, I am annealing after every firing.

Dave

 

[memilanuk]

Just a Question on the Imperial Dry Lube, So if I understand this correctly you are dipping the case neck into the dry lube, shaking it off, charging the case and then seating the bullet.

That's pretty much what I used to do. Seemed like I got more stuff on the *outside* of the neck and shoulder, than I actually did *inside* the neck, where I wanted it. As such, I switched to using a bore mop on a handle, and dipping it into a tub of the straight up dry lube, without the media. Once the mop gets loaded up, it takes very little to keep it charged.

I load my 6.5x47 with .002" neck tension. I very rarely get a force reading at all when I seat my bullets

Apparently as of now, they are all under 2lbs seating force.

Those two sound pretty much contradictory in my experience. I'd say something is very off, somewhere, as far as measurements goes. Which one... dunno.

 

[Dusty Stevens]

That's pretty much what I used to do. Seemed like I got more stuff on the *outside* of the neck and shoulder, than I actually did *inside* the neck, where I wanted it. As such, I switched to using a bore mop on a handle, and dipping it into a tub of the straight up dry lube, without the media. Once the mop gets loaded up, it takes very little to keep it charged.





Those two sound pretty much contradictory in my experience. I'd say something is very off, somewhere, as far as measurements goes. Which one... dunno.

The press part is easy to check on a scale

 

[davecb]

That's pretty much what I used to do. Seemed like I got more stuff on the *outside* of the neck and shoulder, than I actually did *inside* the neck, where I wanted it. As such, I switched to using a bore mop on a handle, and dipping it into a tub of the straight up dry lube, without the media. Once the mop gets loaded up, it takes very little to keep it charged.





Those two sound pretty much contradictory in my experience. I'd say something is very off, somewhere, as far as measurements goes. Which one... dunno.

I probably didn't word it right. What I meant was that the seating force gauge is graduated in two lb increments. Being the gauge needle doesn't move when I'm seating a bullet, I'm assuming they are taking less than two lbs of seating force.

 

[jsthntn247]

Do this test.
Take 3 cases. Use 3 different bushings for the neck. Use a stiff nylon brush in the neck and seat bullets.
record the numbers
Take 3 more, use the same bushing. Dont touch the inside of one neck, use a nylon brush in one and a steel wool wrapped brush in the other. Seat bullets and record the numbers.
I have done it so I'll go ahead and give you my opinion. Seating force measures friction mainly. The actual neck tension has a small effect on the seating force. Neck tension shows on target. Im not saying not to sort, its easy, so do it. But its down my list of importance. Sort by oal to the bullet ogive, it will give you a similar result. Longer oal had more resistance to seating. Then go shoot them and see how much it matters.

Try coating the inside of your necks with liquid graphite. It pretty much eliminates friction readings from showing on the force gauge and any seen differences are tension related.

 

[memilanuk]

I probably didn't word it right. What I meant was that the seating force gauge is graduated in two lb increments. Being the gauge needle doesn't move when I'm seating a bullet, I'm assuming they are taking less than two lbs of seating force.

No, that's pretty much what I understood you were saying.

And I'm saying that for 2 thou neck tension, that doesn't sound even remotely right.

 

[bichettereds]

I probably didn't word it right. What I meant was that the seating force gauge is graduated in two lb increments. Being the gauge needle doesn't move when I'm seating a bullet, I'm assuming they are taking less than two lbs of seating force.

Something doesn’t sound right with your force gauge if that’s what you’re seeing.

 

[Richard Coody]

No, that's pretty much what I understood you were saying.

And I'm saying that for 2 thou neck tension, that doesn't sound even remotely right.

sure wouldn't be what the readings on my 21st century would be. i would have to be bullet diameter to get those kind of readings.

 

[Alex Wheeler]

Try coating the inside of your necks with liquid graphite. It pretty much eliminates friction readings from showing on the force gauge and any seen differences are tension related.

I disagree. Tried that long ago. Nothing beats a polished layer of carbon so far that I can find.

 

[Bart B.]

What I meant was that the seating force gauge is graduated in two lb increments. Being the gauge needle doesn't move when I'm seating a bullet, I'm assuming they are taking less than two lbs of seating force.

If the gauge indicates 2 pounds seating force while the bullet goes into the case, that's exactly a 2 pound force.

A 2 pound weight on a bullet would do the same thing. It's a constant force that indicated uniform neck walls thickness and surfaces.

 

[mikecr]

Which situation is most critical in achieving uniform muzzle velocity, pressure curves or whatever regarding bullet and case neck diameters?

Diameter difference between die neck and loaded round neck, commonly called tension.

Interference fit; the diameter difference between bullet and the resized case neck inside diameter.

Bullet's seating force, when reloading, in pounds.

Bullet's pull or extraction force, when fired, in pounds.

None of these directly contribute to MV, as none of these directly indicate neck tension.
Tension is spring back grip(squeeze) against seated bullet bearing. Seating force is a friction measure, not a squeezing measure.
There is currently no tool available that can directly measure our neck tension.

So to make a best comparative correlation between seating force and neck tension, friction must be very well controlled. Like Alex said, the carbon layer provides this.
In this endeavor, it is detrimental to increase seating forces beyond what actual tension would cause. And it is detrimental to increase interference fit beyond that providing actual tension.
All excess serves only to work the brass and boost variances in it.

Also, depending on the situation you're putting yourself in, one of seating force or pull force may be more correlating to tension than the other.