How much neck tension ?

[Zero333]

0.0015" to 0.003" works good for me. Most of the time I run 0.0015" and use a light crimp for semi-auto ammo.

Weather it's 0.002" or 0.003" makes little difference as long as all brass has consistent/same neck tension.

More than 0.003" is a bit too much for me personally and less than 0.001" is too little.

 

[Dave M.]

0.0015" to 0.003" works good for me. Most of the time I run 0.0015" and use a light crimp for semi-auto ammo.

Weather it's 0.002" or 0.003" makes little difference as long as all brass has consistent/same neck tension.

More than 0.003" is a bit too much for me personally and less than 0.001" is too little.

When you are talking about squeezing the utmost accuracy out of an F class bolt gun, neck tension can and does make a big difference. Please don’t give the OP the impression that neck tension has little effect on the performance of the rifle, because this is simply not true.

 

[SKWERLZ]

I have 5 separate rifles that all shoot best with 3.5-5.5 thou of “neck tension”. Don’t assume accuracy is only between 1-3 thou.
Dave

My 338 edge definitely preferred more, running 5 thou on that.

 

[JFrank]

My load data won’t help the OP but does reinforce the value of getting on the right bullet hold/ dimensional difference for your set up, and not to be confused with friction/seating resistance.
You can have either one but only one helps meaning a lubed neck and plenty of hold yet moderate seating force or rough seating force with light hold.
Testing a bit usually solves the puzzle.

Jim

 

[DLT]

To those who brush the carbon out of necks before sizing, do you use the same brush to lube inside of necks before using the expander ball or mandrel ?

 

[Sandstorm]

Time to buy a better die.

I use Short Action Custom....aint nothing better in my book....well perhaps there are many better
I just dont need them....or any others.

 

[JFrank]

To those who brush the carbon out of necks before sizing, do you use the same brush to lube inside of necks before using the expander ball or mandrel ?

The burnished carbon inside the necks IS the lube

 

[DLT]

The burnished carbon inside the necks IS the lube

I thought you had to lube up the neck for the mandrel ??

 

[Sandstorm]

I thought you had to lube up the neck for the mandrel ??

Only if your going to size cases from 6.5 to 7mm or up to 30 cal.
But after sizing with a bushing die i just finish the job with a mandrel and no lube.
Ps i dont clean my brass.. plenty of carbon left after mandlel and a quick dry brush
Through the neck

 

[DLT]

we

Only if your going to size cases from 6.5 to 7mm or up to 30 cal.
But after sizing with a bushing die i just finish the job with a mandrel and no lube.
Ps i dont clean my brass.. plenty of carbon left after mandlel and a quick dry brush
Through the neck

Oh oh oh. So if I was going from .264 od to .270 with a mandrel I should be fine with the cooked on carbon from firing ?

 

[quest450]

 

[Webster]

I have a redding non bushing full length sizer. Using my adg brass annealing after every firing and using the expander ball, my necks come out consistently .270. Loaded rounds measure .271 I took the expander ball out and the necks came out of the die measuring .268 which gives .003 neck tension and that’s as small as I can go. I figure most run between between .001 and .003 tension. Most of my other full length dies will have .002 neck tension but it’s rough coming back through the neck with the exp ball meaning the die is closing the neck down way too much. I bought a mandrel die body from 21st century with the appropriate size and it came in .001 undersized what it’s marked so I can’t test any improvements using it

A neck diameter measurement has little to do with actual grip on the bullet. It's adjusting the diameter to get some unknown grip on the bullet. The actual grip is determined by the neck thickness, hardness, how much you anneal, and how much you strectched the brass. It's called hoop stress a complicated calculation. You try different neck diameters and look for a group improvement. Video's with the nations top shooters all most all say 0.002" no more than .003".

Added later:
Firing, sizing and a mandrel all deform the brass and induce work hardening. As others have said some kind of neck lube helps over come the friction to get the bullet moving. The same as reducing bullet grip?

 

[DLT]

No doubt he probably knows more than me but I don’t think he knows as much as he thinks he does. Its neck tension. I have not had any rounds come apart from traveling or unloading a round jammed in the lands with .002 or even .001 neck tension. I could see it happen in an AR or a total freak accident. I’m miles more careful than that

 

[Dave M.]

My load data won’t help the OP but does reinforce the value of getting on the right bullet hold/ dimensional difference for your set up, and not to be confused with friction/seating resistance.
You can have either one but only one helps meaning a lubed neck and plenty of hold yet moderate seating force or rough seating force with light hold.
Testing a bit usually solves the puzzle.

Jim

Great example. Clearly the .261 bushing (more neck tension) provides far less dispersion than the .262 bushing did.
Dave

 

[Alex Wheeler]

Theres three main components when we are talking "neck tension". The interference fit of the bullet in the neck, the friction between the bullet and neck, and the hardness of the brass.

The interference fit is pretty simple, you can alter that with bushings or mandrels. This is what has the most effect on target in my experience.

You can do a lot of different things to prep the neck before seating. Most of us will brush it with a nylon brush and that works well. But you can experiment with different lubes, graphite or one shot. You can ultra sonic the carbon out or leave it in. This is the area that has the greatest effect on seating force. Seating force in my opinion is down there with bullet concentricity. It just does not show up on target as much as you would it should. But the different neck preps do show up on target.

You can anneal your brass to soften up the brass and get more consistent seating force. I find on combos that like light neck tension annealing works well, but if the rifle wants a lot of grip on the bullet annealing may open up your groups. All of this stuff should be tested, do not fall into the trap of testing only at the reloading bench. The best seating force at the bench may not be the best on target.

 

[DHD]

To those who brush the carbon out of necks before sizing, do you use the same brush to lube inside of necks before using the expander ball or mandrel ?

When I chuck up a nylon brush in the drill for the ID of case necks, it's just to add a little more smoothness in bullet seating. I've found that the smoother a bullet seats, the more consistent my OAL is. A squeaky clean case neck (SS pin tumbled or a fresh anneal) makes my bullet seating more grabby and I've seen more inconsistent OAL measurements. I'm not intending on removing the left over carbon with the nylon brush though it does remove some obviously.

As to lubing the case necks before sizing/expanding, I keep heavy duty large bamboo sticked cotton swabs with Imperial on it to add a small amount of lube for the ID. I don't tend to size in large batches so the extra time doesn't bother me. Honestly, the lube is used as much for protection of the mandrels than the case necks. Them things ain't cheap and I want them to out live me.

These types of threads pop up from time to time and I like to see others experiences/opinions. As has been mentioned by some very knowledgeable folk here, the "neck tension" or as Alex Wheeler more properly described it "interference fit" is important where it matters most so maybe my expenditure was worthwhile afterall...

 

[Bill Norris]

No doubt he probably knows more than me but I don’t think he knows as much as he thinks he does. Its neck tension. I have not had any rounds come apart from traveling or unloading a round jammed in the lands with .002 or even .001 neck tension. I could see it happen in an AR or a total freak accident. I’m miles more careful than that

I totally agree. My question for him is simply if I test my hand loads with the inside diameter at .003 below the bullet diameter vs. .001 more or .001 less than the .003 he is harping on and my groups are better than the .003 then am I supposed to throw caution to the wind and follow his example and give up my best groups just because he said so ? I think not. He CANNOT dictate the accuracy of anyone's loads by his findings. We all know no two rifles react the same. We all know no two handloads are the same done by different people around the globe and we all know there are far too much variations in climates and atmospheric conditions that come into play with tuning our handloads. I call BS on his theory.

BUT, from my measurements on my 6PPC brass loaded neck outside diameter of .265 it just so happens that with my .261 bushing I'm using I see exactly .240 inside neck diameter. However I have not done the neck tension test on my hand loads yet to see if my rifle will like a different bushing and with using common sense that will be my next test after seating depth testing.

 

[Dave M.]

To those who brush the carbon out of necks before sizing, do you use the same brush to lube inside of necks before using the expander ball or mandrel ?

Brush once in and once out.
No lube for inside neck.
No expander ball.
No mandrels.
Dave

 

[jimmymac]

Brush once in and once out.
No lube for inside neck.
No expander ball.
No mandrels.
Dave

Same here. When I'm feeling really frisky, I may go two strokes. lol

You forgot one thing. No tumbling! I like the inside of my necks dirty.

 

[Kracken McGraw]

Same here. When I'm feeling really frisky, I may go two strokes. lol

You forgot one thing. No tumbling! I like the inside of my necks dirty.

That’s where my ocd kicks in. Should I be spinning this brush when going in and out. lol.