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Neck Tension

I am not sure you can have anything more than ,003" neck tension. At some point you will yield the case neck when you seat the bullet. The way to find out is to pull a seated bullet and measure the neck OD and compare it to the loaded neck OD.
 
ok I am bored because I don't have a Winter project so I conducted a test on some .223 Remington brass.

.223 Remington Neck Tension Test

Five cases were annealed, FL sized with a Redding FL sizing die w/o an expander, expanded with a .2235” diameter gauge pin, trimmed to 1.750” and neck turned with a K&M turner to .012” neck wall thickness.

The cases were then annealed and sized with the Redding FL die w/o an expander and expanded with a .223” diameter pin. The neck OD was measured at .2465”. The neck ID was calculated by subtracting 2x the .012” neck wall thickness. The result was .2225” ID. The ID was measured with a .2225” GO pin and a .2225” NO GO pin. The Go pin would pass through the neck but the NO GO pin would not pass.

52 grain Berger Target bullets were seated in the cases. The base of the bullet was seated .190” beyond the case mouth. The neck diameter was .2484” after the bullets were seated. The apparent neck tension was calculated as .2484” minus .2465 which equals .0019”.

The bullets were pulled with a RCBS collet puller. The empty neck diameter was measured at .2478”. The actual neck tension was .2484” minus .2478” or 0.0006”.

So then I wondered if a smaller case neck would make more neck tension. I again sized the cases with the Redding FL die (no anneal) and expanded the necks with a .222” diameter gauge pin. The neck OD was .2458” diameter. Then I seated 52 grain Bergers. The neck OD was .2485” diameter. The apparent neck tension should be .2485” minus .2458” or 0.0027”. I pulled the bullets and the empty neck diameter was measured at .2479” diameter. The real neck tension was .2485” minus .2479” or 0.0006”.

The results show that a .223 Remington fully annealed case with a 0.012” thick neck can only produce 0.006” neck tension no matter what the starting neck diameter is reduced to.
 
ok I am bored because I don't have a Winter project so I conducted a test on some .223 Remington brass.

.223 Remington Neck Tension Test

Five cases were annealed, FL sized with a Redding FL sizing die w/o an expander, expanded with a .2235” diameter gauge pin, trimmed to 1.750” and neck turned with a K&M turner to .012” neck wall thickness.

The cases were then annealed and sized with the Redding FL die w/o an expander and expanded with a .223” diameter pin. The neck OD was measured at .2465”. The neck ID was calculated by subtracting 2x the .012” neck wall thickness. The result was .2225” ID. The ID was measured with a .2225” GO pin and a .2225” NO GO pin. The Go pin would pass through the neck but the NO GO pin would not pass.

52 grain Berger Target bullets were seated in the cases. The base of the bullet was seated .190” beyond the case mouth. The neck diameter was .2484” after the bullets were seated. The apparent neck tension was calculated as .2484” minus .2465 which equals .0019”.

The bullets were pulled with a RCBS collet puller. The empty neck diameter was measured at .2478”. The actual neck tension was .2484” minus .2478” or 0.0006”.

So then I wondered if a smaller case neck would make more neck tension. I again sized the cases with the Redding FL die (no anneal) and expanded the necks with a .222” diameter gauge pin. The neck OD was .2458” diameter. Then I seated 52 grain Bergers. The neck OD was .2485” diameter. The apparent neck tension should be .2485” minus .2458” or 0.0027”. I pulled the bullets and the empty neck diameter was measured at .2479” diameter. The real neck tension was .2485” minus .2479” or 0.0006”.

The results show that a .223 Remington fully annealed case with a 0.012” thick neck can only produce 0.006” neck tension no matter what the starting neck diameter is reduced to.
Very interesting test.... in you opinion why would people see differences on there target at distance when they test differing amounts of neck tension. With all other variables equal?
 
Very interesting test.... in you opinion why would people see differences on there target at distance when they test differing amounts of neck tension. With all other variables equal?
Probably because of the temper in their brass. My test was with fully annealed brass. If they do not anneal every time their brass will be harder and can apply more compression on the bullet. The tensile strength (yield) for brass can vary from 18,000 to 45,000 psi depending on the degree of temper (fully annealed to full hard).
 

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