Neck Tension - .270

[Lee Q. Loader]

.270 Win is the only bottleneck cartridge I load. I neck size only with the Lee collet die.
I've been loading these for years, but only now am I questioning my neck tension. I'm not having any problems with my loads, but I just want to be sure I'm doing it right.
Funny how sometimes reading this forum seems to raise questions in my mind that I didn't think about much before.
Anyway, how do you test for proper neck tension? The only thing I found on a search was to load a dummy round and see if I could push the bullet deeper by hand against a 2" X 4".

 

[LRDGCO]

The importance of neck tension is really two-fold: 1) that it be sufficient to ensure there is no bullet set-back in the magazine under recoil; 2) that it be consistent. There is no magic number. If after seating, bullets you load are not shifting under reasonable hand pressure, that is enough. That such tension is consistent for each case loaded is important.

 

[troy fairweather]

about 2 thousands is the norm for rifle rounds, the lee die does a good job keeping thing consistent. there are a few things that can change neck tension. like brass hardness, you can aneal your brass to help keep the neck more consistent, the other is difference in neck thickness, get the necks the same thickness and you will be more consistent.

 

[243winxb]

The little 5.56 has a bullet pull of 35 pounds minimum. Measure the neck od before and after seating the bullets.

30-06 in chart.

 

[rsrocket1]

The typical number is that the neck should be about 3 mils (0.003") narrower than the bullet.
There are bench rest shooters who hand feed cartridges where there is virtually no neck tension and shoot the bullets just fine. The problem is that if you used this "lack of tension" in a normal bolt or autoloading gun, the bullet will be driven into the neck and your pressures will be all over the place. If you can't push or pull the bullet out of the neck by pinching the bullet with your index finger and thumb and you measure the COL before and after chambering and it doesn't get shorter by about 0.002" you are fine. If it does get shorter, be sure not to chamber and re-chamber that cartridge repeatedly.

 

[fguffey]

Anyway, how do you test for proper neck tension? The only thing I found on a search was to load a dummy round and see if I could push the bullet deeper by hand against a 2" X 4".

I have tension gages, none of my tension gages measure tensions. All of my tension gages measure in pounds, I am the fan of all the hold I can get. I am quite happy with 45 pounds of bullet hold. There is a hydraulic seating die that is available to reloaders, the gage is calibrated in pounds. I am not guessing but if it was possible to measure tension the gage would be marked on in tensions and somewhere out here there would be a conversion for tensions to pounds.

I am familiar with crush fit and interference fit; all of the presses I have operated have been calibrated to pound.

F. Guffey

 

[JFrank]

I took this picture as a spoof; It actually works It does not measure in tensions either

 

[old heeler]

You can get one of these

https://lewilson.com/k-m-precision-...ard-force-measurement-ram-and-dial-indicator/

 

[fguffey]

It does not measure in tensions either

I have had tension gages for years, none of them measure tension, I have deviation gages that measures deviation in pounds, others measure deviation in thousandths.. Other times I have had to use a strain gage. There is one reloader that uses load cells, and then there is the hydraulic press and there is the dial indicator that is calibrated to pounds. Not one of them could figure a way to measure tension, and if there was a conversion chart for tensions to pounds I am sure someone would have found it by now.

And the next press that will be made will allow a reloader to measure the amount of effort required to overcome the cases ability to resist sizing.

F. Guffey

 

[.308 Norma]

Funny how sometimes reading this forum seems to raise questions in my mind that I didn't think about much before.

Ha! And here I thought I was the only one that this forum affected in that way.

 

[JFrank]

Well said

 

[JFrank]

I have tension gages, none of my tension gages measure tensions. All of my tension gages measure in pounds, I am the fan of all the hold I can get. I am quite happy with 45 pounds of bullet hold. There is a hydraulic seating die that is available to reloaders, the gage is calibrated in pounds. I am not guessing but if it was possible to measure tension the gage would be marked on in tensions and somewhere out here there would be a conversion for tensions to pounds.

I am familiar with crush fit and interference fit; all of the presses I have operated have been calibrated to pound.

F. Guffey

I’ve heard of the Newton conversion, something about dividing the unit into the factor???
Using my bathroom scale (a health meter ) while seating Bullets I had a consistent seating force if 12 health’s;
Jim

 

[lightman]

It is generally considered that if you can't push the bullet into the case by hand that your neck tension is ok. Now, you can turn your case necks and use bushing dies to make it more consistent but I doubt that you will see much difference on the target using a factory hunting rifle.