7mm rem mag bullet pull

[Blade1]

How many pounds of pressure should it take to move a seated bullet if neck tension is correct?

 

[Frank in the Laurels]

Man buddy there's a lot of variables with that answer... First neck wall thickness, it varies a lot manu/manu, how far down it was squeezed, neck tension, also varies from bushing size used and die maker, bullet outside diameter, believe it or not but it's there, sealant used to waterpproof , bearing surface length...on and on it could go !! Exact foot pounds ??? Not sure anyone ever measured it..but it's not that much with a mounted press to me . 20 lbs is my guess or less...

 

[g0rd0]

I have no idea, good question.
I use a forster die with collet that screws into my press, when I have it set there is a gentle tug and the bullet comes free

 

[Blade1]

80 to 100 lbs is where im finding my best accuracy but im have some issues with thin necks that i just cant seem to get that much grip on. It shows in the groups.

 

[MagnumManiac]

Not all neck tension is equal, to get the exact same tension, regardless of intereference fit, the brass would first have to have the same neck wall thickness, and then, more importantly, hardness. Soft brass provides less tension, hard brass provides more tension, but less deflection.
This is why we run .001"-.005" neck reduction.
I have 2 barrels in 300WM, the lightweight barrel likes firm seating @ .003" reduction in annealed brass, the heavy barrel likes no more than .0015" reduction, and the groups stay the same at .001".
You do realise that it really is a moot point, because the neck only holds the bullet for the primer ignition, as soon as the case pressurises, the neck is the first thing to expand and releases bullet grip very early on in the ignition process.
In reallity, neck tension only needs to resist primer ignition and to stop bullets falling out.
Distance from the rifling is more important to group size than neck tension in most situations.
If you feel that 100lbs is necessary then use it.

Cheers.
gun)

 

[Blade1]

Not all neck tension is equal, to get the exact same tension, regardless of intereference fit, the brass would first have to have the same neck wall thickness, and then, more importantly, hardness. Soft brass provides less tension, hard brass provides more tension, but less deflection.
This is why we run .001"-.005" neck reduction.
I have 2 barrels in 300WM, the lightweight barrel likes firm seating @ .003" reduction in annealed brass, the heavy barrel likes no more than .0015" reduction, and the groups stay the same at .001".
You do realise that it really is a moot point, because the neck only holds the bullet for the primer ignition, as soon as the case pressurises, the neck is the first thing to expand and releases bullet grip very early on in the ignition process.
In reallity, neck tension only needs to resist primer ignition and to stop bullets falling out.
Distance from the rifling is more important to group size than neck tension in most situations.
If you feel that 100lbs is necessary then use it.

Cheers.
gun)

Thats where im finding consistant tight grouping. If i fall under 80lbs my groups will tend to start opening up. I shot some rounds at 60lbs and it wasnt good at all.

 

[ShtrRdy]

How do you measure seating pressure?

 

[sp6x6]

Then you have bench rest shooters,that some engage rifling and it pulls bullet outwhen not shot and cycled back

 

[Frank in the Laurels]

I must be reading this wrong.. I thought you wanted to know how many pounds of force it takes to bull a seated bullet out ?? Can't read after 21 credits past masters degree.. I must need comprehension skills refresher... The 60-80-100's your mentioning I never heard of.

 

[Gene]

How do you measure seating pressure?

What is your method to measure seating pressure?

The K&M arbor press with force attachment is the best. There are many variables - neck thickness, bullet pressure ring, bushing size, etc.

 

[Blade1]

What is your method to measure seating pressure?

The K&M arbor press with force attachment is the best. There are many variables - neck thickness, bullet pressure ring, bushing size, etc.

a wood block on the bathroom scales. Push til the bullet slips. It goes all at once.

 

[MagnumManiac]

a wood block on the bathroom scales. Push til the bullet slips. It goes all at once.

Honestly, that would be like using a slide rule to measure the ogive of a bullet.
I think you are wasting your time.
This is what I do, load 5 rounds in .001" increments to .006". Bushing style dies work best for this. Shoot each batch, and take the tightest group as the besr tension.
Unless you are shooting benchrest and getting groups in the .1's, it's not worth the efforts you are going to. The biggest thing is consistent neck tension, I only achieve this by annealing every other firing.

Cheers.
gun)

 

[dok7mm]

Thanks for clearing that up. I was scratching my head, trying to figure out how you were coming up with those numbers. That is a method I was unaware of. I'm with MagnumManiac, you'll have much better success with the standard neck tension solution. It is a step, just like adjusting seating depth is, for consistent ammo.

 

[Blade1]

Honestly, that would be like using a slide rule to measure the ogive of a bullet.
I think you are wasting your time.
This is what I do, load 5 rounds in .001" increments to .006". Bushing style dies work best for this. Shoot each batch, and take the tightest group as the besr tension.
Unless you are shooting benchrest and getting groups in the .1's, it's not worth the efforts you are going to. The biggest thing is consistent neck tension, I only achieve this by annealing every other firing.

Cheers.
gun)

if i can measure every case and it breaks at the same poundage how can that be right. Pressure is pressure. Weight is the best indicator. I may not know everything about reloading but i make my living as a quality control inspector. I stress test plastic parts on a daily basis. You cant rely on bushing size completely. I can measure .002 neck tension on 2 different brass that have been fired different amount of times and have 60lbs different in bullet grip. If you dont think so try it. You can rely on pounds of pressure. Its a constant. Each to his own im sticking with the scales.