Neck tension for 6.5 CM bolt gun

SinCityJets

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Mar 11, 2020
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I have read you need to have .001-.003 neck tension, however with .002+ it was VERY hard using the arbor press (no lube on neck or bullet). My loaded diameter is .2905. Obviously the bullet is .264. Wall thickness is about .1325. With a .289 bushing (.0015 tension) it is bearable, but .0288 is ridiculous.

Is .0015 enough neck tension, and should I be using some type of bullet/neck lube?

Thank you!

Chad
 

Snuby642

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I use lube.
The most convenient way I found was imperial dry lube (grafite).

Comes in a kit with 2 small canisters one full of grafite and the other small balls
to distribute it.

Dunk neck to the start of the shoulder, tap in canister lid to remove excess
and load powder then bullet as normal.

Bullets glide in and no welding noticed on storage rounds.

Edit: on longer bullets you can dip the bearing surface of the bullet if you prefer.
 
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Supersubes

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I have read you need to have .001-.003 neck tension, however with .002+ it was VERY hard using the arbor press (no lube on neck or bullet). My loaded diameter is .2905. Obviously the bullet is .264. Wall thickness is about .1325. With a .289 bushing (.0015 tension) it is bearable, but .0288 is ridiculous.

Is .0015 enough neck tension, and should I be using some type of bullet/neck lube?

Thank you!

Chad
Instead of doing the math, measure the sized neck diameter and compare to the loaded neck diameter. I’ve had a number of neck bushings that were nowhere near the listed diameter. .0015 should be fine fwiw.
 
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Dthomas3523

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New brass or fired?

How are you measuring the neck tension? I find without using a pin gauge, you’ll need to measure outside diameter before loading and outside after. I prefer using a pin gauge. Then I can set my tension based on how it feels grabbing the pin gauge.

I set mine to hold a .002 under pin gauge without allowing it to fall free into case with gravity. On new cases, there can be a ton of friction which jumps the seating pressure up to 80-100+psi.