Help me understand

[ka30270]

I was messing around with some loose Berger 30 caliber 175 VLD Hunting bullets a little while ago and I was taking some measurements just because. My numbers for bearing surface did not match up with the numbers posted on Bergers website. What am I doing wrong? These numbers give a bearing surface of .517 compared to the listed .392. Measurements were taken using a Hornady comparator.

 

[Barrelnut]

The Hornady comparator tools are not held to tight tollarences and are not precise enough to compare readings from tools that Berger uses to measure and verify bearing surface measurements. The Hornady tools are made to use in your reloading room for things like comparing different measurements in your environment. For example, if you are sorting bullets by bearing surface variance, all you need is a tool that will allow "comparison" measurements. You are not purchasing a tool machined to the precision that will allow you to verify bearing surfaces as measured by Hornady.
Don't believe me? Purchase another set of Hornady comparators and use them for measurements. You will be amazed at how far off they are from your current set.
I believe Brownells and others make steel machined comparators that may be manufactured to tighter tolerances and allow more precise measurements than can be used to compare results to the manufacturer, but not the Hornady stuff.

 

[ka30270]

Are you implying that my $35 Hornady comparator set is not laboratory quality? LOL that makes perfect sense. My numbers aren't skewed but my datum lines are. Thank you for straightening me out.