Case Neck Tension

[truck driver]

I read here where some one was getting .002" of neck tension and thought that it was enough. I don't know what cartridge it was but I have been wondering if I was having tension problems with my 35 Whelen AI for a while now and had thought about getting a Factory Crimp die made. I have never read how to measure neck tension so I don't really know how much tension my cases have after resizing them. I was annealing ever 5 loadings and have just recently annealed after each firing.
My Reading full length sizing dies have a long tapered expander button which Reading claims is the best type to use.
So when prepping some cases today I decided to measure the inside diameter of some case mouths to seem how much the necks of the cases were sized.
The inside diameter of my Nosler cases freshly annealed and sized was .354", the inside diameter of a fired case was .364" so the dies are sizing the necks down .010". I also sized some once fired after annealing and the inside diameter was the same .354". I measured some 200gr .358 cal ABs and came up with .357" and some Hornady 200gr .358 cal bullets and came up with .3575".
If I'm thinking right by subtracting the inside neck diameter from the bullet diameter I should get the neck tension. .357"-.354"= .003" .3575"-.354"= .0035" so respectively I should have a neck tension of .003" when loading ABs and .0035" when loading Hornady bullets?

 

[Wyo7200]

There is a formula on accurate shooter or 6mmbr that involves the wall thickness...

Simple formula is to measure the outside diameter of a case before loading, load it and measure again.

Subtract the unloaded case from loaded case and you should have your amount of tension.

 

[Wyo7200]

Actual loaded diameter-((thickness*2)+bullet diameter)= tension

 

[jimbires]

if you are not cutting your case necks , be sure to measure from the exact same spots . this way you will not alter the measurement you get due to case neck varience . I don't think calipers will be good enough for this , I'd use a mic .

 

[kraky1]

I Define case mouth tension as bullet diameter - actual Case Mouth inside Dimension after sizing. Most collet dies with the standard Mandrel will give you about .002. Most of my FL dies leave me .003 - .0035. there is a internet argument that anything more than .002 tension is negated when you seat the bullet. I don't buy that argument and don't think it's that simple.
Different brands of brass seem to have different alloy mixes, different neck thicknesses, and different states of annealing. I think all these things have a huge effect on how much it takes to seat the bullet and how much it takes to release it later on.
The only proof I have of this is a few years of using a collet bullet puller and seeing what it takes to pull some of these bullets.
Lastly the amount of time in storage seems to affect things for me too.... seems like the longer it's been since I've loaded something the tougher it is to pull the bullet. A few benchrest actually take their ammo to the range with the bullet seated long and do the final seating just before the matches. Then of course there are arguments about what is inside your neck after cleaning and what kind of Coatings might be on your bullet. Seems like some of the bench resters are getting down on steel pin cleaning claiming it's just too clean and leaves ever so many tiny dimples in the case neck.... seems to add grip... and more than they want.
Now that I've babbled a lot all I can see is in general I really prefer about .003 - .0035 for my neck tensions.

 

[RiverRider]

I think it's good to try to achieve uniformity, but I think measuring the inside of the neck to determine "tension" is not practical. The tension with which the neck holds a bullet would depend on the elasticity of the brass, which we know changes from firing to firing. A dimensional measurement might be meaningful if all the brass is perfectly and identically annealed, but otherwise I'm afraid it is not.

Better to try than not, though, I'm sure!

 

[Polaris]

I do it by feel. When seating, if I get one that feels particulary loose or tight, it goes into the practice/offhand stack. I have fired some of these for groups and got noticeably more vertical dispersion than in the ones that felt "normal".

I've also noticed a difference in dies. Lee collet type neck dies and Redding neck dies seem to produce the most consistent feel on seating. Redding FL have been a close second, with Lee and Hornady FL bringing up the rear. In fairness, I only have one set of Hornady in .300 sav and the M99 is a notorious brass stretcher. Given the Marbles buckhorn sights and 170 gr FP 30-30 style bullet I load in that one, really a moot point so long as tension is sufficient to hold bullets and not so high as to cause over pressure.

Have also noticed a difference in brass. PRVI and Lapua seem extremely consistent with a "soft and smooth" feel. Norma and Hornady feel "stiffer" and somewhat "springy" and Remfedchester is all over the board depending on caliber and lot. Our minds are more capable than the strongest computer at noting subtle changes not easily quantified by careful measuring. This is the art portion of our hobby.

 

[baltz526]

Here is the Lee crimp die. No need for a custom i'll bet. http://www.midwayusa.com/product/426941 ... -35-whelen

 

[truck driver]

Here is the Lee crimp die. No need for a custom i'll bet. http://www.midwayusa.com/product/426941 ... -35-whelen

I've been told that won't work with the 35 Whelen (AI) Ackely Improved so I would have to get them to make me one.

 

[kraky1]

Sounds like we all have our preferences.....lol!
I played with a lot of Weatherby rifles over the years and have come to love the Norma / Weatherby brass. For me the seating consistency is really really sweet. That's why I was really happy when Nosler seemed to switch over to a Norma build for their brass.... not only is the seating very smooth and consistent for me but it seems like run out on Virgin rounds is pretty darn impressive too.

 

[baltz526]

Here is the Lee crimp die. No need for a custom i'll bet. http://www.midwayusa.com/product/426941 ... -35-whelen

I've been told that won't work with the 35 Whelen (AI) Ackely Improved so I would have to get them to make me one.

The 300 weatherby Crimp die works with my 300 ackley

 

[30-338]

I read here where some one was getting .002" of neck tension and thought that it was enough. I don't know what cartridge it was but I have been wondering if I was having tension problems with my 35 Whelen AI for a while now and had thought about getting a Factory Crimp die made. I have never read how to measure neck tension so I don't really know how much tension my cases have after resizing them. I was annealing ever 5 loadings and have just recently annealed after each firing.
My Reading full length sizing dies have a long tapered expander button which Reading claims is the best type to use.
So when prepping some cases today I decided to measure the inside diameter of some case mouths to seem how much the necks of the cases were sized.
The inside diameter of my Nosler cases freshly annealed and sized was .354", the inside diameter of a fired case was .364" so the dies are sizing the necks down .010". I also sized some once fired after annealing and the inside diameter was the same .354". I measured some 200gr .358 cal ABs and came up with .357" and some Hornady 200gr .358 cal bullets and came up with .3575".
If I'm thinking right by subtracting the inside neck diameter from the bullet diameter I should get the neck tension. .357"-.354"= .003" .3575"-.354"= .0035" so respectively I should have a neck tension of .003" when loading ABs and .0035" when loading Hornady bullets?

Sinclair makes turning mandrel and expander mandrel for 35/50 cal so you can turn necks. Turning mandrels are .002" under bullet dia and expander mandrel .001" under bullet dia and they make expander die 35/50 cal for those mandrels.

If you get those two mandrel and expander die after you size load few using both mandrels and one will be what you need. On plus side using those you don't worry about neck thickness unless you decide to have bushing custom made and loaded dia would be used. As you know I had bushing die made for my 35 whelenAI.

Well good luck

 

[longrangehunter]

The way I've always determined neck tension is to just measure a loaded round, and subtract .003-.004" for all of my rifles. I honestly don't care for them being lighter then that, and in a magazine the recoil can cause issues keeping the bullets from being moved. Super heavy recoiling calibers should be crimped, sometimes I've even found certain calibers prefer to be crimped for accuracy.

Truth is the benchrest guys are single loading and jamming their bullets into the rifling with a light neck tension which allows them to be just be push seated prior to firing them. No good for the guy hunting or in a tactical match when a round must be removed without having to fire it!

A long time ago Fred Sinclair told be to use .004" neck tension and I've never changed that for anything I hand load for that uses a bushing die.

 

[Dwh7271]

PRVI and Lapua seem extremely consistent

PRVI brass has been very good for me fwiw.

 

[ElmerThud]

I think it's good to try to achieve uniformity, but I think measuring the inside of the neck to determine "tension" is not practical. The tension with which the neck holds a bullet would depend on the elasticity of the brass, which we know changes from firing to firing. A dimensional measurement might be meaningful if all the brass is perfectly and identically annealed, but otherwise I'm afraid it is not.

Better to try than not, though, I'm sure!

I agree, brass is not consistent enough either from new production or after firing & resizing to maintain a consistent round to round neck tension.
So, I use a Lee Factory Crimp Die to even the tension out as far as possible.
The net result has been much closer ES and more consistent MV lot to lot of ammunition I reload.
Result!
Go with a Lee FCD, anneal after 3-4 firings and F/L resize to fired headspace dimension. The difference is so worthwhile.

 

[kraky1]

Fwiw... this last week I pulled down some ammo that had been loaded to rid myself of some Winchester primers. One small batch was some 95 ttsx I had loaded in my 270. I had loaded it within the last month. I couldn't believe how hard it was to pull those little bullets with my collet puller. It had to be some kind of function of brass elasticity and the ribs and groove really pulling together!

 

[jimbires]

Fwiw... this last week I pulled down some ammo that had been loaded to rid myself of some Winchester primers. One small batch was some 95 ttsx I had loaded in my 270. I had loaded it within the last month. I couldn't believe how hard it was to pull those little bullets with my collet puller. It had to be some kind of function of brass elasticity and the ribs and groove really pulling together!

getting off track here ..............
did you notice any sign of corrosion ? something happens here that I sure can't explain . some guys see it from time to time , others seem to never see it .

 

[truck driver]

I read here where some one was getting .002" of neck tension and thought that it was enough. I don't know what cartridge it was but I have been wondering if I was having tension problems with my 35 Whelen AI for a while now and had thought about getting a Factory Crimp die made. I have never read how to measure neck tension so I don't really know how much tension my cases have after resizing them. I was annealing ever 5 loadings and have just recently annealed after each firing.
My Reading full length sizing dies have a long tapered expander button which Reading claims is the best type to use.
So when prepping some cases today I decided to measure the inside diameter of some case mouths to seem how much the necks of the cases were sized.
The inside diameter of my Nosler cases freshly annealed and sized was .354", the inside diameter of a fired case was .364" so the dies are sizing the necks down .010". I also sized some once fired after annealing and the inside diameter was the same .354". I measured some 200gr .358 cal ABs and came up with .357" and some Hornady 200gr .358 cal bullets and came up with .3575".
If I'm thinking right by subtracting the inside neck diameter from the bullet diameter I should get the neck tension. .357"-.354"= .003" .3575"-.354"= .0035" so respectively I should have a neck tension of .003" when loading ABs and .0035" when loading Hornady bullets?

Sinclair makes turning mandrel and expander mandrel for 35/50 cal so you can turn necks. Turning mandrels are .002" under bullet dia and expander mandrel .001" under bullet dia and they make expander die 35/50 cal for those mandrels.

If you get those two mandrel and expander die after you size load few using both mandrels and one will be what you need. On plus side using those you don't worry about neck thickness unless you decide to have bushing custom made and loaded dia would be used. As you know I had bushing die made for my 35 whelenAI.

Well good luck

Went to Sinclair's web page and as usual all .35 cal stuff is out of stock. I'll back order the mandrels and the die.

 

[kraky1]

Jim...no corrosion.... these were loaded in the last few weeks so we're pretty fresh. I haven't seen it to the degree you showing in that picture....Wow. I usually try to remember before shooting ammo that's been sitting a long time to just bump a few shells a few thousand's deeper with my seating die. If they move easy I'm good to go but sometimes you hear kind of a "crack" before they move and you know they've taken a little bit of a set.

 

[jimbires]

Jim...no corrosion.... these were loaded in the last few weeks so we're pretty fresh. I haven't seen it to the degree you showing in that picture....Wow. I usually try to remember before shooting ammo that's been sitting a long time to just bump a few shells a few thousand's deeper with my seating die. If they move easy I'm good to go but sometimes you hear kind of a "crack" before they move and you know they've taken a little bit of a set.

I don't remember for sure , but I'm guessing these were pulled apart within a month of them being loaded . it's just an old pic .