Hornady 6mm creedmoor ammo less than optimum case length after once fired

[akz28]

Hello. I am reloading 6mm creedmoor with my once fired Hornady ELD Match bullets @ 108gr.
Problem is that at least half of my ammo is below the optimum case length of 1.910
A lot my once fired ammo is measuring 1.800 to 1.900
Will this greatly affect accuracy at 100 yards and beyond.

So my question is, is 1.8xx too short for great accuracy?
Is there a +/- tolerance to the 1.910 that wont have any affect on accuracy.

I hate to throw it away so I will probably use it for barrel warm up ammo if it is no good for accuracy.
At around $2 a round I hate using the good stuff to warm up the barrel with the first 5 shots.
Thank you.

 

[918v]

How short is your shortest case?

 

[akz28]

Actually one was 1.78...but that was just one. Other than that, quite a few have measured 1.85x.
I thought I could get some reloads out of this brass. So I hope its not trash.

 

[FCS]

Max case length is 1.920”.
1.915” is plenty short for trimmed case length.
1.900” case length is going to cause you any appreciable accuracy issues.
1.800” case length, that’s over 0.100” too short….did you mean 1.890” case length?

 

[FCS]

Actually one was 1.78...but that was just one. Other than that, quite a few have measured 1.85x.
I thought I could get some reloads out of this brass. So I hope its not trash.

Brass from factory ammo, once fired, sized and not trimmed is measuring 1.780” for case length?

 

[918v]

Maybe his caliper is not working correctly?

 

[FCS]

Pictures would be most helpful.
Calipers not working or maybe transposed #s?

 

[918v]

R u measuring the brass with the fired primer still in the case?

 

[akz28]

Thank you all. Not measuring with fired primer in the case. I have the Hornady digital caliper, but I have another I can try. I will get a few pictures. And it is once fired brass which is really puzzling to me. Let me go measure a few and get back here with actual measurements on several cases.

 

[akz28]

Happy to report it was the caliper. I forget I had another somewhere from my model building days.
Anyway, checking with another caliper and all brass cases are reading around 1.909 - 1.915.
Thank you all for your help in confirming 1.8xx was not normal. I can still take back my Hornady caliper since its only a month old.

 

[Mike Casselton]

Change the battery in the caliper and it'll probably be just fine

 

[akz28]

Thank you, I will try that before taking it back.