Sierra match king question

U

Urban_Hunter

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Oct 15, 2012
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30 cal 168gr loading 308 win.

My COAL is varying .012. I know sp can vary some to deformity but is this normal for the HP? I measure some of the bullets and they seem to vary in OAL by about the same. I set my die to set the first one at 30 of the lands but it's hard to monitor because the bullets are different lengths. I've loaded Nosler BT and some SST with these dies, never seen this much variance. Normal?

I've always used the fired case method for setting seating depth and never got around to getting a comparator. Looks like I need one.
 
Jcalder

Jcalder

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They'll vary a bit. You'll need a comparator if you want it tighter.


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trap55555

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I think they will vary a bit also. In reality your BTO (Base To Ogive) is not likely varying that much, unless you have adjusted the die :D .

The problem is how do you adjust or check your seating depth and have confidence that they are the same bullet to bullet? I came to recognize this issue, and like you have recognized also, I went ahead got the Hornady comparator set. So now I set, measure and record the BTO for my loads, to the point I can't tell you the COAL is my loads without going and measuring. I also log the Base to Lands (BTL ?) measurement for each the bullets that I load for. So I'm loading and testing by 0.XXX off the lands.

In my experience blems,seconds,... seem to vary even more.

Good Luck Be Safe,
 
jlanecr500

jlanecr500

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The seater die should be contacting at the ogive. Measuring off the nose will give erroneous measurements. Like Jcalder and trap5555 said, you really need a comparator. If you want to be cheap, get a large nut that is about 1" hex. Drill a .305" or .306" hole in it. Slip it on the bullet when measuring oal. That is exactly how a comparator works.
 

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