COL Variance


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PecosRiverM
September 18, 2008, 08:13 PM
I was noticing a difference of .002 - .003 measuring the ogive. They all are under the max (so are not on the lands).

My question is:

Will this affect my grouping much?

These are for a .270
Range was 2.822 - 2.825

Or is this the norm?:confused:

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ranger335v
September 18, 2008, 09:07 PM
WHAT? An OAL variance of .003"! That will blow a quarter inch group out to three and a half inches! :D

Or, well, no it really won't. Actually, you will never see a difference on the target with a difference equal to the thickness of a sheet of paper.

EShell
September 18, 2008, 09:15 PM
If your seater plug fits the bullet profile reasonably well, your case head to *ogive* length should be more consistent than that.

Conversely, I would expect the COAL measured at the meplat to vary at least this much.

Measurement inconsistency can give this much variation.

If you are actually measuring to the ogive and not the meplat, and you're not seeing the effect of a distorted case rim, I would suggest that you lap the seater plug to fit the bullet properly or send the plug and several bullets to the die maker to have him correct it.

Walkalong
September 18, 2008, 11:11 PM
That is not bad at all.

243winxb
September 19, 2008, 09:00 AM
http://www.redding-reloading.com/techlinepages/seatingdepth.htm That little will Not affect your group IMO

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