NECK TENSION

[Nick Caprinolo]

It has be stated over and over again the the way to accuracy is reputability. By that I mean that all components of a load are nearly exactly the same.

I am anal when it comes to powder charge and seating depth as well as grouping bullets by weight. I am now mainly concerned with neck tension.

1. How do you achieve the same neck tension?

2. What is the proper amount of tension?

3. How do you measure it?

4. Is it the same for all calibers.

5. How do you determine the proper size bushing for dies?

I am assuming that you must turn necks to a common diameter. Lots of questions I know, and I have probably left a few unasked.

 

[Bart B.]

The industry "tension" standard is how many pounds of force is needed to pull the bullet out of the case neck. Called bullet pull or extraction force.

1 - 2 pounds for single round loading for best accuracy objectives. Maybe less than a pound in some uses.

5 - 10 pounds for most hunting rifles with box magazines.

20 - 60 pounds for military service rifles.

There are specs only for military small arms ammo. None published for commercial ammo or reloading data.

 

[Bob L.]

The industry "tension" standard is how many pounds of force is needed to pull the bullet out of the case neck. Called bullet pull or extraction force.

1 - 2 pounds for single round loading for best accuracy objectives. Maybe less than a pound in some uses.

5 - 10 pounds for most hunting rifles with box magazines.

20 - 60 pounds for military service rifles.

Is there a specific tool or instrument available to measure this?

 

[Bart B.]

Is there a specific tool or instrument available to measure this?

Hook a hand scale on a bullet puller gripping the bullet all horizontal on a table top. The cartridge head in a shell holder fixed in place.

Pull the bullet noting the scale reading. Measure 5 rounds to get an average.

Commercial ones like arsenals used on military ammo cost several hundred bucks

 

[Nightraider]

Cartridges don't care about neck tension so long as it's accounted for during load development and constant/ consistent after.

 

[Falfan2017]

If you measure your seating psi with something like a 21c hydro seater or km pressure pack seater the carbon in the neck seems to have a huge effect on the seating psi. I have my brass necks turned to .011 and seat a 243 bullet using a 264 bushing. So .264 neck before loading and 265 with bullet seated. If I don’t brush the neck out that shows up as 40-60 psi on the hydro seater. If I do brush the necks out with a nylon brush they come to 20-25 and they seem to be more consistent. Does that matter on target? Who knows. I do know that when I was using too much psi to seat it didn’t work well at all.

 

[SGK]

https://www.ampannealing.com/articles/42/annealing-under-the-microscope/

scroll down to "repeatable, consistent neck tension"

 

[Bart B.]

If I do brush the necks out with a nylon brush they come to 20-25 and they seem to be more consistent. Does that matter on target? Who knows. I do know that when I was using too much psi to seat it didn’t work well at all.

The more consistent bullet pull force is, the more consistent interior ballistics will be. As will be exterior ballistics

 

[Bart B.]

https://www.ampannealing.com/articles/42/annealing-under-the-microscope/

scroll down to "repeatable, consistent neck tension"

Bad link. Please check link address.

 

[Nick Caprinolo]

So, how do I determine the proper size bushing in comparison to outside diameter neck diameter?

 

[SGK]

Bad link. Please check link address.

Link works when I click on it

 

[HTSmith]

So, how do I determine the proper size bushing in comparison to outside diameter neck diameter?

A bushing that is .002" under the loaded round diameter generally works for me with my 6BR's. I got this from the Redding site. 'Course I'm kind of an oddball--I use a Lee Collet die for sizing my necks most of the time.

 

[Alex Wheeler]

How much neck tension is just like how much powder. Theres no answer. I am aware of rifles that have shot at the top level using from .0005-.007" neck tension. They got there by testing. The targets will tell you. Yes brass yields but the targets keep changing.

 

[foxguy]

A bushing that is .002" under the loaded round diameter generally works for me with my 6BR's. I got this from the Redding site. 'Course I'm kind of an oddball--I use a Lee Collet die for sizing my necks most of the time.

Just Curious? Are you using an 6MM BR Lee Collet Die, or some other similar caliber?

TIA,

Steve

 

[Coyotefurharvester]

I have one FL die(non bushing) in 204 Ruger that was sizing 0.007-.008 under loaded size with Hornady brass. That sporter barrel shot tiny little almost single hole groups. Found a Redding bushing die on clearance, setup to have .002 tension. Groups with same load opened to holes touching, thought I had damaged the crown. Went back through my notes, little light bulb lit up. Sized some with old die, back to a ragged hole. Several of my rifles shoot well at .002. Some I have no bushings for and shoot very well at .004-.005. So nothing written in stone for my reloading notes.

 

[HTSmith]

Just Curious? Are you using an 6MM BR Lee Collet Die, or some other similar caliber?

TIA,

Steve

Yep it is a 6MM BR Lee collet die. I had to special order it. Works good.

 

[Bob L.]

Hook a hand scale on a bullet puller gripping the bullet all horizontal on a table top. The cartridge head in a shell holder fixed in place.

Pull the bullet noting the scale reading. Measure 5 rounds to get an average.

Commercial ones like arsenals used on military ammo cost several hundred bucks

Thanks, Bart. I figured a commercial one would be expensive. Your method looks good.

 

[Mikemontminy]

I’ll size my brass so the necks are .001 under. Then run a expander mandrel into the necks to expand .0005. When I’m done I’ll check each one with a pin gauge to make sure it doesn’t lift the case out of the loading block. If any of the cases feel different I’ll run the mandrel thru again. When they all feel the same I prime all the cases. One last step I came across was to put the pin gauge into the neck of the primed case and let it fall in under its own weight. The air in the case will escape between the pin gauge and the inside of the neck. Takes about three to five seconds. If it takes longer I run a larger expander mandrel in a drill and just let the tapered part of the mandrel touch the chamfer on the inside of the neck. That usually takes care of it so the pin gauge drops in quicker. After all that the cases are ready to charge. When I seat the bullets with my arbor press they all feel the same.

 

[BartsBullets]

It has be stated over and over again the the way to accuracy is reputability. By that I mean that all components of a load are nearly exactly the same.

I am anal when it comes to powder charge and seating depth as well as grouping bullets by weight. I am now mainly concerned with neck tension.

1. How do you achieve the same neck tension?

2. What is the proper amount of tension?

3. How do you measure it?

4. Is it the same for all calibers.

5. How do you determine the proper size bushing for dies?

I am assuming that you must turn necks to a common diameter. Lots of questions I know, and I have probably left a few unasked.

Nick what are Shooting? Or competing in?

If it’s short range neck tension is way down on the list as far as priorities.

But I agree with Falfan2017 I do exactly the same.

Bart

 

[ebb]

I as once told buy a national champion benchrest shooter that neck tension was irrelevant if bullets were jammed into the rifling. Is that your experience Bart?