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What Neck Tension Bushing?

Torchy

Private
Full Member
Minuteman
May 29, 2017
181
67
NV
Hey Guys,

I know neck tension is a complex subject but for simple purposes, how many thou under (outer loaded neck diameter) are you using?

Let’s assume the brass is annealed and you’re not doing any neck turning.

This is for a bolt 300NM cadex.

Also curious what you’re using for 6.5CM bolt gun.
 
I think most people use .002" under loaded neck diameter. Some others probably use .001" under loaded neck diameter. Those are probably the two most common options.
 
For 6.5cm I’m running .290 which is .002” under factory 140gr eldm loads
 
I'm using .289 with Lapua brass for 6.5CM
 
I am using a .290" bushing on Lapua 6.5 cm also.
But I notice it takes less pressure seating the bullet in once fired vs new brass.
Seems to me if the wall thickness varies and you use the same bushing the tension will change right?
I was thinking about getting some pin gages to check the I.D. of the neck after sizing to know how much tension / press there actually is. Anyone do this?
 
With starline brass i was using .290 but switched to .288 when i got some free once fired hornady.