243 win brass

[mw0248]

my Lee 2nd edition reloaders manual shows a max case length for 243 win. at 2.045";

I just purchased 100 rnds of new 243 win brass, and I mic'd several cases at random (25-30 ea), and they mic'd at 2.033 - 2.038; Most were at 2.038;
None of them were near 2.045; This deviation is driving me nuts;

My max. OAL in my Browning X-Bolt is 2.695 (100 gr. Hornady BTSP);
I want to be about .015 - .020 off the lands;

I can't get consistency with this deviation in case length; Any input?

 

[moparman]

The info I use has the trim length at 2.035. If the jump or jam distance is what you are worried about being consistant that shouldnt change once the seating die is set to the desired oal. There may be oal variations too if you don't sort your bullets.

 

[Terry]

Case length has nothing to do with OAL. You can trim them all to the shortest length. They will grow after firing.
Seat your bullets a little long. Color one or two with a sharpie. When you seat them the rifling should leave a mark. Reduce the OAL until you get a very faint mark. (You may have to recolor the bullet.) The faint mark becomes your "0". Reduce the OAL to your desired length.
This is best measured with the Hornady comparator or some similar device. Measuring base to bullet tip is not accurate or consistent.

 

[25AI260]

i don't think the deviation of .002 will hurt you for your 1st firing anyway... but take one or two of your shortest cases an run then threw your FL die before you fire them.. an see what happens...

 

[mw0248]

thanks for the info guys; I will cut them all to 2.036, and mic my bullets as well

Mike Walker

 

[H2OBUG]

Shold not matter on OAL --unless you are crimping--then there may be an issue

 

[expiper]

New cases are usually .010 shorter than max reccommended length....or what we call trim length...you wouldnt want them at max rite outa the box.....when they grow to 45 trim em to 35.....the chamber is usually around 55(that is determined by the reamer)....Roger

 

[mw0248]

thanks for all the info; I learn something new all the time