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case gage and comparator


Cali_Ed

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Something I should have asked the get go. How important are these tools. I've just been using my caliper.

I want to find the max oal for my specific rifle. Or is it typical to go of 2.8? I know finding the oal I'd have to subtract a certain amount so the bullet is not in the lands. Thank you.

Is this process more towards bolt action or critical for a semi as well?

Edited by Cali_Ed
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Also, how does the measurements from the ogive compare to c.o.l? I'm very confused. With the comparator I'm getting a measurement of 2.224 vs the 2.8 with out the comparator. I know it's a diffrent measurement but how do I connect the dots lol.

Using this new tool really shows the diffrence in the loads I have sitting waiting for testing :'(

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The measurement you are stating is the case overall length inside the chamber.The OAL can be longer and still fire. Bullet touching in the lands can effect accuracy but still fire.The key is having the brass less than the size of the chamber.

I trim my brass to 2.015" Max length coal. OAL max size of magazine without touching. I DONT know if this will help.

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Better yet - load and shoot what you have.  This is for practice, anyway.  Be consistent with your practices, like I said before.  You want these to have the same velocity, basically.  Case length affects crimp tightness, measure every powder charge, load up the same bullet depth (COAL measurement, mostly).  They'll be consistent.  <thumbsup>

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The Sinclair Meplat Trimmer is a handcranked tool which will quickly and accurately uniform the bullet tips (meplats) of long range bullets or loaded ammunition. This tool includes a caliber specific Delrin™ housing, tool steel cutter, aluminum frame and a comfortable crank handle. Additional Delrin™ housings (see chart below) may be purchased to change calibers. We suggest trimming approximately .005" of material from the bullet tips which will uniform the ballistic coefficient (B.C.) with a B.C. reduction of about 2%. The Meplat Trimmer is easy to set up and adjust to the trim cut you desire. We also suggest sorting long range match bullets by base to give length using our Sinclair Bullet Sorting Stand or our comparators prior to trimming meplats.

 

 

 

 

 

 

  How much of a difference are you reading ? I have not seen much of a difference , but some use this tool to help sort out bullets for long range .

Edited by survivalshop
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Something else I thought about - one of the first lessons in Precision Measurement.

 

SuzukiRay knows EXACTLY what I'm talking about with this one, too.  <thumbsup>

 

The very first thing you need to suspect is the measuring equipment - verify it, and know how to use it.  When measurements come up different, you don't suspect the part - you verify the equipment, very first.

 

Are you using a digital vernier caliper to measure your COAL?  Are you practiced in applying the correct pressure to the thumbwheel each and every time?  Easy way to check this is with a verification piece that is a (machined) known length.  Say the thing is precision machined to 1.750" - the length of a trimmed 5.56 case.  You measure that known piece, and see what you get.  If you get different numbers that what that verification piece is, then you're measuring wrong.

 

I'll get pics in here tomorrow of what I'm talking about.  You can buy a HF caliper set that has these verification pieces in it, and it's cheap, and you can get your technique down. 

 

Don't doubt your die set yet, brother.  <thumbsup>

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 Shoot them , they will be fine. Those COL's will be effected by the hollow point cone & even Match bullets will not be uniform at the tip ( thats what that tool above is for ) When I set my seating die up , I rarely get 0.002" difference .

   You won't see a difference in Velocity with those COL's.. Now ,if you seat the bullets where they are just off the Lands of the rifling , you might see some funny Velocity readings, because there is very little leeway when only a few thousands of an inch off the lands . Seat them @ the 2.8"+/- & you will be fine , I usually get mine around 2.79+/-. 

  Just remember that different bullet Manufacturers & different weight bullets may not all have the same olgave & if seating close to the lands ,they must be measured independently, for safety.

  I like the steel lock nut die sets like the RCBS , as said that rubber o-ring on the Lee is good for it to lock down , bit it could give a little & may be why your readings are off a little . I use a wrench or Channel locks to tighten my die lock nuts/ring. I have Dillon lock rings on most of my Dies because they go on my Dillon or my single stage press's. 

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There are lots of people on here that are more expert than me.  But, when you measure with a caliper, you want to put firm pressure.  i don't know about Lyman, but my caliper has a wheel on it that spins when the pressure is too much.  Light pressure could lead to mis-alignment of the cartridge or case and give a bad reading.  If you think it is necessary, measure the same piece more than once.

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Here's how you can apply too much or too little pressure, and come up with different measurements.  Just an example.  The reference piece is a 2" zero gauge for a micrometer. 

 

It takes practice to make accurate measurements, it really does.  Don't doubt the reloading die just yet. <thumbsup>

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Edited by 98Z5V
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As usual Tom is right, get a standard to check your calipers or micrometers by, it'll save you lots of headache. I usually wiggle calipers just a smidge with gentle pressure on the thumb wheel, to help make sure I've got the best parallelism between the jaws of the calipers and the piece I'm measuring. Don't crank down too hard though either, you can botch your measurement like that.

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There are lots of people on here that are more expert than me. But, when you measure with a caliper, you want to put firm pressure. i don't know about Lyman, but my caliper has a wheel on it that spins when the pressure is too much. Light pressure could lead to mis-alignment of the cartridge or case and give a bad reading. If you think it is necessary, measure the same piece more than once.

just noticed mine does the same thing I suppose that's when you have applied enough pressure. Thanks

Something is fucked up with your seating die setup, to have a difference overall of 0.013" in COAL. My observation.

with running my hornady bullets I noticed I had to raise the ram up twice to get to the correct depth. Seem right? Edited by Cali_Ed
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