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Bart B. · April 10, 2013, 05:38 PM

A friend of mine reloaded the same .308 Win. Federal brass case 57 times full length sizing it every time. All bullets shot into about 3/8ths inch at 100 yards. Maximum load used; 42 grains of IMR4895 under Sierra 168's and Fed. 210 primers. No loosening of the primer pocket whatsoever. Case was never annealed. Chamber was a standard SAAMI spec one; no tight neck.

Case neck tension in the ammo industry is typically referred to as the bullet's release force needed to push (or pull, if measured) it out of the case. It needs to be uniform to about a 10% spread for best accuracy. Too much will increase pressure quite a bit as well as degrade accuracy; if it's too much, the case head may rupture when fired. MIL SPEC 22 and 30 caliber rifle ammo has 40 to 80 pounds of release force. Commercial ammo is somewhat less. Most reloaded rifle ammo has a release force for its bullets between 5 and 30 pounds.

Having seen the results of firing a round whose case neck had hard-bonded to the bullet (disimilar metal stuff) and the neck shot off with the bullet, the primer readily fell out of the case when it was ejected. Its shooter commented that the rifle had a lot more recoil as well as an extra loud report. That ammo had been reloaded some 20 years earlier. So, there is a limit to what neck tension or release force can be as far as safety is concerned.

April 10, 2013, 05:38 PM	#11
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	A friend of mine reloaded the same .308 Win. Federal brass case 57 times full length sizing it every time. All bullets shot into about 3/8ths inch at 100 yards. Maximum load used; 42 grains of IMR4895 under Sierra 168's and Fed. 210 primers. No loosening of the primer pocket whatsoever. Case was never annealed. Chamber was a standard SAAMI spec one; no tight neck. Case neck tension in the ammo industry is typically referred to as the bullet's release force needed to push (or pull, if measured) it out of the case. It needs to be uniform to about a 10% spread for best accuracy. Too much will increase pressure quite a bit as well as degrade accuracy; if it's too much, the case head may rupture when fired. MIL SPEC 22 and 30 caliber rifle ammo has 40 to 80 pounds of release force. Commercial ammo is somewhat less. Most reloaded rifle ammo has a release force for its bullets between 5 and 30 pounds. Having seen the results of firing a round whose case neck had hard-bonded to the bullet (disimilar metal stuff) and the neck shot off with the bullet, the primer readily fell out of the case when it was ejected. Its shooter commented that the rifle had a lot more recoil as well as an extra loud report. That ammo had been reloaded some 20 years earlier. So, there is a limit to what neck tension or release force can be as far as safety is concerned. Last edited by Bart B.; April 10, 2013 at 06:50 PM.