Hornady Modified Case/OAL Gauge Issue
- Thread starter Mr.Moa
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HEAL
Member
ONE THING I HAVE NOTICED WHILE MEASURING OGIVE TO LANDS IS RIFLE HAS TO BE VERTICAL SO BULLET IS REALLY CENTERED. IF MEASUREMENT IS MADE HORIZONTALLY BULLET RESTS AT AN ANGLE AND A POSSIBLE WRONG MEASUREMENT CAN BE OBTAINED.
Very true! I think when Norma adopted the 6.5-284 Winchester, which was a wildcat at the time, they added their name and immediately pursued standardization, but, being a European company, they started with CIP standardization first (released in 2007), and then took their time with SAAMI standardization.
Thank everyone for all of the replies! I eventually got the case smoothened out. I polished the inside of the case pretty heavily which helped a lot. I ordered dies at the same time as the modified case, but I still have yet to receive them. Therefore I was a little limited in my route to fix the issue. I'm getting pretty consistent results now. I will be using neck sized fired brass and plan to move on to calculating ogive to shoulder to make sure my distance to the lands is adjusted correctly to the brass I'll be using.
I do have a question though. It seems when I measure to the lands with my EOL and VLD i come up with a different number to the lands. In my head it should be the same distance to the lands regardless of bullet selection if the only thing I change in my testing method is the bullet. Using the same gun, comparator, and tools. Why would a get a different number.
I do have a question though. It seems when I measure to the lands with my EOL and VLD i come up with a different number to the lands. In my head it should be the same distance to the lands regardless of bullet selection if the only thing I change in my testing method is the bullet. Using the same gun, comparator, and tools. Why would a get a different number.
Mr.Moa:
It's due to the different shapes of the bullets. You have a very smooth shape (the bullet), fitting into a very unsmooth shape (the lands and grooves of a barrel). Unless the nose of the two bullets are identically shaped, one bullet will protrude into the barrel a different distance, relative to the datum diameter of the comparator. You can really only compare like bullet shapes - each different one has it's own "length" to the lands.
It's due to the different shapes of the bullets. You have a very smooth shape (the bullet), fitting into a very unsmooth shape (the lands and grooves of a barrel). Unless the nose of the two bullets are identically shaped, one bullet will protrude into the barrel a different distance, relative to the datum diameter of the comparator. You can really only compare like bullet shapes - each different one has it's own "length" to the lands.
vancewalker007
Well-Known Member
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The EOL and VLD have different Ogive positions , plus I don't think the bullets are even the same length. The EOL has a hybrid ogive and the VLD has a sharp secant ogive.
That said what it means it the ogive is a different distance from the bullet base between these bullets. In fact the ogive will vary between all bullet types. Your measurements will be in the same ball park but never the same.
Okay thats what I was thought the reasoning would be and why I checked both bullets to start with. I figured using the comparator is only a relative distance and that between different bullets I would need to recalculate my "relative" distance to lands switching between different bullets. My EOL to EOL and VLD to VLD numbers were consistent
I'm thinking the ogive shape is the reasoning as since the comparator is kind of a relative measuring tool. I figure the comparator touched exactly where my rifle did, I might see the same numbers bullet to bullet
Badfinger
New Member
This is incorrect the bullet cannot move around or lean to one side or the other when pressed into the lands. Think about it....
Philip J Theodhor
Active Member
What I would do is to make a custom case out of one that has been fired out of your rifle.
First select a case that was recently shot in your rifle (it must be from your rifle only)
Clean this case after manually just depriming it. then complete cleaning the case,& champher the OD & ID of the neck . Make certain that it will accept a bullet completely with no hang upsthrough the neck. (In my case a .264 diameter bullet) Obtain a 5/16" x 36 TPI Tap and a letter L (.281.dia. drill bit) Drill through the cases base where the primer pocket is. After drilling and tapping is complete you will have a case that is custom to your rifle and can easily establish your rifles C.O.A.L. and deterime the correct jump. You can watch you tube on a how to if you need help. This has worked for me. With just a little time and effort you can complete this task in your home basement.,and the end result will please you!
HEAL
Member
MY COMMENT IS BASED ON USING A HORNADY'S LOCK & LOAD COMPARATOR TOOL WHERE THE PROVIDED CASE (260 REM) HAS A SOMEWHAT LOOSE NECK DIA THAT CAUSES BULLET TO LEAN DOWN IF MEASURING HORIZONTALLY. AS BULLET IS PULLED DOWN BY THE TOOL IT SHARPLY GRABS SOLID TO LANDS AND APPEARS A RIGHT MEASURMENT. AFTER A COLLECTION OF MEASUREMENTS IT CAN BE OBSERVED A NUMBER OF SIMILAR OR EQUAL READINGS, BUT BY SUDDEN, A DRASTIC DIFFERENT READING IS SHOWN, AS IF BULLET ENTERED MORE (0.030" OR SO DIFFERENCE). MY COOPER MODEL 22 260 REM RIFLE HAS GIVEN 2.225" CBTO READINGS WITH BERGER 135 CLASSIC BULLETS. NOW THAT I CLEANED IT GIVES ME ALL SORTS OF READINGS (I AM NOT SAYING IT CAUSES IT. LIKE 1.555", 1.980" VERY REPEATEDELY) AND THEN RETURNS TO 2.225" ON SEVERAL SIMILAR READINGS. I HAVE BEEN LEARNING TO TAKE THE LONGEST READING AS THE CORRECT ONE PROVIDED THAT THE CARTRIDGES MADE FREELY FEED CHAMBER. ANY COMMENT WILL BE VERY MUCH WELCOMED.
