Increase in load pressure
Posted 16 November 2009 - 10:08 pm
Posted 16 November 2009 - 10:15 pm
I am in the process of changing my R93 barrel for a new one and with the new barrel I shall be buying new cases acknowledging that even though the new barrel is still an R93, there will still be a chamber difference.
Bear in mind that case shoulders will also move forward especially in slack chambers - have you measured your shoulder datum length and compared it to a new case - you may be surprised how far it has crept forward and that going into a tight chamber........could be the reason
Posted 16 November 2009 - 10:44 pm
Posted 16 November 2009 - 11:23 pm
Excuse the relative newbie here, what's a shoulder datum when it's at home?!
When its at home (yours preferably) it's the length from the headstamp to the point where the shoulder starts to bend in towards the neck - to be accurate with this measurement you really need a shoulder gauge
Works on the same principles as a bullet comparator
Posted 17 November 2009 - 06:34 am
Ok so to do that I literally take a fired case, fill it with water, weigh that and that's what you're after?
Yes but keep in mind this is not really a fault finding exercise, more a theoretical exploration in to what happens with different powder weights. With the internal case capacity it means QL can calculate almost specific pressure traces which means the final data of chamber pressure and muzzle velocity is more accurate. I've had all sorts of problems reloading for my mates Howa .308, very tight chamber, very small throat etc. My standard .308 ammo will not even chamber in his rifle! He likes Winny silver tips, the fire formed cases come out with neck tension.
Posted 19 November 2009 - 11:52 pm
Now in Winchester brass.
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