308 brass oal ??

[black_ump]

not sure if it matters but iam shooting from a semi auto not bolt gun so with that in mind whats the oal for 308 BRASS and are you useing calipers or an indicator with a stack up to check oal ?

calipers arnt as accurate so iam thinking of going the indicator way

 

[JSTARSZ]

Re: 308 brass oal ??

Are we talking Cartridge Overall Length (COAL) and if we are the book will tell 2.80 is the COAL. That being said that does not take into consideration how far that would have jump start the bullet to the lands. You can look at the Hornady Lock-N-Load Overall Length Gage or Semi's to help you out in this department.

If you are using a magazine and it is standard size then you can get away with 2.810.

Yes, I always use a caliper and a cartridge gauge when I reload. One to check length and the other for chambering dimensions.

You can check you mags with the caliper and see what the OAL it will accept.

Hope that helps

 

[Lt. Arclight]

Re: 308 brass oal ??

Most reloading manuals list what the brass should be trimmed to. Sierra's recommendation is 2.004". A simple dial indicator can measure to the 0.00" but 2.05" is close enough.

When I read your post-you are talking about the BRASS and not the loaded cartridge-correct?

 

[JSTARSZ]

Re: 308 brass oal ??

I guess I was wondering the same thing as what he was speaking of so I went with COAL. But, as you say...2.004 or 2.005 is what the book says for trimming.

 

[black_ump]

Re: 308 brass oal ??

just the brass is what iam talking about...... my barrel is already pressed into my trunion so i cant make a mold of the chamber to see where it ends and the lands begin

ya i want to use a dial indicator, not sure if calipers will be as accurate as i want to be

 

[Lt. Arclight]

Re: 308 brass oal ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: black_ump</div><div class="ubbcode-body">just the brass is what iam talking about...... my barrel is already pressed into my trunion so i cant make a mold of the chamber to see where it ends and the lands begin

ya i want to use a dial indicator, not sure if calipers will be as accurate as i want to be </div></div>

If you want to find out where the rifling begins-take a fired case and barely size the neck to hold a bullet finder tight.

Use a sharpie marker and blacken the bullet and press it into the case just enough to hold it firmly-gently close the bolt on the dummy round the rifling will push the bullet into the case.

Then,gently eject the round,trying not to disturb the bullet. Provided the bullet didn't move, you'll see exactly where the lands touched the bullets ogive-then measure the coal using a bullet comparator and a dial caliper-then you'll know EXACTLY where the rifling begins. Then set your COAL about 0.010" shorter. And you'll be 10 thou off the rifling. Simple. Really

 

[InTheWeeds]

Re: 308 brass oal ??

I cut all mine to 2.005" I got a fresh box o Lapua's in and they all came in at 2.008"

 

[black_ump]

Re: 308 brass oal ??

thanks for the heads up

 

[Wil]

Re: 308 brass oal ??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: black_ump</div><div class="ubbcode-body">not sure if it matters but iam shooting from a semi auto not bolt gun so with that in mind whats the oal for 308 BRASS and are you useing calipers or an indicator with a stack up to check oal ?

calipers arnt as accurate so iam thinking of going the indicator way </div></div>


consistency is key... 2.00, 2.005. 2.013... matters not.


do or do not... there is no try

 

[vinconco]

Re: 308 brass oal ??

This tool will tell exactly what the chamber length is. Factory chambers are usually quite a bit longer than the listed max case length.

Sinclair Chamber Length Gauge