Redding instant indicator

Well, after jimm asked me to check this thread out I will add this....
1. Belted ammo varies widely in measurement from the case head to the belt (which is where SAAMI measures headspace)from manufacturer to manufacturer. Win & Lapua are typically smaller and Federal is thicker. This is why most smiths say to neck size and headspace off the shoulder for more consistent accuracy.
2. Since the 300 Win Mag headspaces off the belt SAAMI doesn't have a set dimension for the shoulder and reamers can vary a bit in this area, as can brass....I have seen Lapua brass be as much as 20 thou short.
3. Since there is no "datum" line set for the 300 shoulder any measurent from a Stoney Point tool or a Redding indicator does not tell you how short or long your fired brass is.
4. The brass will be different, especially when it was used in a ladder test with different powder charges, resulting in different pressures. Plus as others mentioned...different case capacity, wall thickness, grain structure, etc. All of these will determine how much or little the brass flows durng the shot and how much it springs back.

Now with this said, the Redding or the Stoney Point tools will tell you how consistent your brass is....and that is the name of the game....not that it is 1 thou or 10 thou back.....once you find something that works you want to duplicate it with every shot and those tools let you duplicate the headspace of every piece of brass to insure the needed consistency.

And just to stir the pot some more....the bump and chamber method is very inaccurate due to the plunger type ejector of a Remmy pushing on the case and the camming power of a Remmy bolt. It requires a "feel" and can be used to check shoulder bump but is not accurate for how much you are bumping it....
 
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Well, after jimm asked me to check this thread out I will add this....
1. Belted ammo varies widely in measurement from the case head to the belt (which is where SAAMI measures headspace)from manufacturer to manufacturer. Win & Lapua are typically smaller and Federal is thicker. This is why most smiths say to neck size and headspace off the shoulder for more consistent accuracy.
2. Since the 300 Win Mag headspaces off the belt SAAMI doesn't have a set dimension for the shoulder and reamers can vary a bit in this area, as can brass....I have seen Lapua brass be as much as 20 thou short.
3. Since there is no "datum" line set for the 300 shoulder any measurent from a Stoney Point tool or a Redding indicator does not tell you how short or long your fired brass is.
4. The brass will be different, especially when it was used in a ladder test with different powder charges, resulting in different pressures. Plus as others mentioned...different case capacity, wall thickness, grain structure, etc. All of these will determine how much or little the brass flows durng the shot and how much it springs back.

Now with this said, the Redding or the Stoney Point tools will tell you how consistent your brass is....and that is the name of the game....not that it is 1 thou or 10 thou back.....once you find something that works you want to duplicate it with every shot and those tools let you duplicate the headspace of every piece of brass to insure the needed consistency.

And just to stir the pot some more....the bump and chamber method is very inaccurate due to the plunger type ejector of a Remmy pushing on the case and the camming power of a Remmy bolt. It requires a "feel" and can be used to check shoulder bump but is not accurate for how much you are bumping it....

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Just to add to Chris' last comment...the shoulder may also not be what you feel binding...so you may have already pushed the sholder back a bunch, but the case may still chamber hard due to binding somewhere else...

JB
 
Thanks Chris for the add'l input . Plenty to think about.By the way , new Lapua brass is .010 shorter than the shortest of the 4 fired cases . I am referring to the measurement obtained with the Redding gauge . I suppose I could dissassemble the bolt to get a better feel but would rather use a gauge of some sort to set up the body die .

JB , the cases have never been bumped back, only collet neck sized . That is why I am asking about this now as I was thinking it might be time to bump the shoulders back so they are all the same . Also , all cases less than .007 close practically as smooth as new cases. And the case lengths are .010 under max.

What about the Cerrosafe , anyone have experience with it ?

I appreciate y'alls willingness to take the time to share your expertise.

Jim B.
 
Jim
That's kinda my point...there is no guage for the shoulder measurement on a 300 Win Mag....what Redding made is just their version and could vary a bunch from my reamer (Pacific Tool and Guage Match finisher). So the Redding guage can't tell you tht they are 5 short or 6 long....but you can use the indicator to get them all the same....
 
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the shoulder may also not be what you feel binding...so you may have already pushed the sholder back a bunch, but the case may still chamber hard due to binding somewhere else...


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"tis also true. Some dies do not squeeze the arse area in enough and it can bind up things- but usually this happens upon extraction. Food for thought...
 
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