284 Win Case Length Question

[Potshot21]

Howdy Folks,

So I'm new to reloading, and one of the calibers I am reloading for is the .284 Winchester. I've got all my once-fired Winchester brass tumbled and resized. So next thing I did was bust out my verniers and check the case lengths and came out to 2.372". Go check my Lyman manual and it says the Trim-to-length is 2.160 and case length is supposed to be 2.170! So next thing I do is check some of the factory loaded Winchester ammo and it measures up to 2.365".

Now I'm not sure what to think! The factory loaded cases are way over what my Lyman manual says they should be. So what do the pros here think I should do? Trim them all down to 2.160 as the Lyman manual suggests? Or trim them back to factory length and have at er?

Thanks for your help!

 

[Alpheus]

Are your calipers broken? Try measuring something of known size, like the bullet diameter of the factory rounds.

 

[wilbar]

Try posting a pic of your calipers measuring a case. Are you actually reading the vernier scale or are they digital?

 

[Potshot21]

D'oh! Thanks guys, turns out my calipers are downright garbage with a wildly wandering zero! Time for a real set I reckon...

 

[wilbar]

I'd go with a dial caliper.

 

[Eagleye]

I have a set of Mitutoyu Digital Vernier calipers, and they have proven trustworthy over the 5 - 6 years I have been using them.

I also have a very accurate Helios 0 - 1" [0-25mm] Micrometer. It reads to 5 decimal places on the imperial scale, or 4 decimal places on the metric.
Very precise, but hard on batteries. Dave.