|
February 23, 2013, 12:21 PM
|
#1 |
|
Junior Member
Join Date: February 11, 2013
Posts: 3
|
C.0.A.L variations
I have a rcbs rockchuck press and dies and am noticing some inconsistencies with my C.O.A.L. I am getting a margin of error of plus or minus .0015. This leads to a difference of .003 at the extreme.
I am measuring from the ogive so it shouldn't be a variation in bullet tips. What I am wondering is.. Is this normal and if not what are some possible causes? I am certain the die lock nut is tight. |
|
|
February 23, 2013, 12:25 PM
|
#2 |
|
Moderator Emeritus
Join Date: June 25, 2008
Location: Austin, CO
Posts: 19,578
|
Normal and irrelevant.
__________________
Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley |
|
|
|
February 23, 2013, 04:00 PM
|
#3 |
|
Senior Member
Join Date: February 15, 2009
Posts: 8,927
|
Bullet jacket copper stuff is not perfect in its metalurgy and dimensions. The ogive curve in the pointing die at the last stage of making a run of bullets will not be duplicated exactly for that reason. Plus, the lead core the jacket's formed around is different too, and it may push out or otherwise deform the bullet shape a few microinches.
A couple thousandths spread in the actual point on the loaded round's bullet ogive to the case head is not an issue and totally normal. They'll still shoot 1/2 MOA at 1000 yards if otherwise quite uniform and shot with good handloads in a proper rifle. One can soft seat their bullets so they seat back a few thousandths by the rifling when chambered and eliminate that insignificant error. Besides, this better centers the bullet in the bore so it'll be less deformed in shape when fired. Of the several dozen things required in making bullets shoot accurate, this one's about 3rd or 4th from the bottom. |
|
|
|
February 23, 2013, 08:08 PM
|
#4 |
|
Senior Member
Join Date: December 3, 2002
Posts: 1,264
|
You're using too many decimal places. 3 digits is more than enough. Agreed; normal and insignificant.
|
|
|
|
February 23, 2013, 08:23 PM
|
#5 |
|
Senior Member
Join Date: January 27, 2010
Location: AR
Posts: 1,401
|
Brian nailed it!!
|
|
|
|
February 24, 2013, 09:40 AM
|
#6 | |
|
Senior Member
Join Date: February 9, 2011
Location: Just outside Cleveland, Ohio
Posts: 722
|
Quote:
__________________
The private ownership of firearms is an American Heritage. Anyone who disputes that is Anti-American and unpatriotic. NRA Life Member |
|
|
|
|
February 24, 2013, 10:01 AM
|
#7 |
|
Senior Member
Join Date: July 18, 2010
Location: Independence Missouri
Posts: 4,585
|
Quote: Brian nailed it!!,,,, well sort of, Bart B. Triple nailed because he explained WHY, and Brian didn't bother with that.
__________________
Keep your Axe sharp and your powder dry. |
|
|
 |
|
|
