Compressed load and OAL and Pressure

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Afy

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Dec 31, 2006
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The Sierra Maunal lists 39.5 gr with a 120 gr SMK seated to a COAL of 2.785 inches as a copressed load.

However if I seat to a COAL of 2.91 inches, it is no longer a compressed load. Will pressure go up or down?
 
Any time you increase the OAL on a given charge with the same bullet, your pressure will be lower. If you are using a different (longer) bullet, be careful, as you might seat too deep and spike the pressure.
 
It will go down slightly, because of the increased case capacity with the long seated bullets.

Compressing a charge has no effect on pressure one way or the other as long as it is a safe load to begin with.

rcmodel
 
Ok then a follow on...

the 120 GR SMK is 1.179 inches long.. seated at 2.910 COAL means there is only .297 inches actually in the neck/case... which is > caliber .260

What effect would the BT design have on this? Or should I just stop worring and obessing and go shoot the damn rifle already?
 
The only sure way to find out what you need to know, as far as load development, powder charge, seating depth, etc, is:

Go shoot the Damn Rifle Already!

You can stew & worry over all the minor details, and none of it does a bit of good until you start testing loads at the range!

rcmodel
 
Ok... tomorrow morning I am off to the range to go shoot...
 
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