Newbie OAL variance question

[fastford]

Finally trying to put all this stuff I bought to good use! GAP 260AR will be here tomorrow so i was tryin to load some rounds up. I was shooting for a OAL of 2.8050. I am getting between 2.8000 - 2.8075 is this a problem or ok? I am using the Redding comp seating die. 139 scenars with remmington brass.

Chris

 

[jimi]

Re: Newbie OAL variance question

if you are measuring from the meplat, id say that sounds normal, there would be that much variance just in the size/shape of the hollow point itself id think? dont quote me on that.

i was told once to trust the die, as that doesnt change. any variance you get on the verniers is just bullet shape size, or case shape/size

 

[jeremybowlin]

Re: Newbie OAL variance question

Plus 1 on above. get the tool to measure off the bullet Ogive. It will give you accurate measurments.

 

[vman]

Re: Newbie OAL variance question

These two bits of equipment are fantastic

http://www.sinclairintl.com/.aspx/pid=35663/Product/Hornady_Lock_N_Load_OAL_Gauge__standard_

Allows you to determine the OAL that would have you kissing the lands.

http://www.sinclairintl.com/.aspx/pid=35...70__7mm__30_cal

This tool then allows you to read the length from the case head to ogive of the projectile. This is the most consistent way to measure loaded round length.

 

[fastford]

Re: Newbie OAL variance question

so what i am seeing is normal?

 

[k2peaker]

Re: Newbie OAL variance question

It's normal from my perspective even using the Redding comp seater. I typically see a OAL variance of .001" to .017". While I have used the Sinclair OAL tool for determining initial jump from lands, I usually measure OAL with my calipers and shoot for an average of where I want to end up.
At some point, I'll probably move to measuring from the Ogive like others have said. The comparator that I have is the Sinclair "hex" one -- it's just a minor pain to throw on the bullet and measure. But, enough of an extra step that when I'm in "high volume" reloading mode, I skip it as I'm ok with the OAL variance due to meplant variances. Maybe using one of the comparators that attach to your calipers would verify more consistently? Like with all of my reloading, it's a question of "good enough" relative to your application/accuracy requirements. If you think about those variances in the absolute sense, they're pretty small numbers. I'm not a BR shooter by any means. LR Tactical is my application -- different game for sure.