223 OAL problems

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jdm66

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I just started reloading for rifle and have run into a problem with my OAL. Rifle is a Sako 85 varmint. So I want to start working up a load with 77g SMK. Using the hornady OAL tools got a measurement of 1.830 for CBTO that gives me a cartridge OAL of 2.230 and if I'm going to bump back 0.010 from the lands that brings it down to 2.220 OAL. Both the Lyman manual and Alliant's reloading page gives 2.260 as the minimum length or pressures will be too high. I can't figure out what's going on. Is this ok to be under OAL by this much? Thanks
 
That's a long bullet and will take up some case capacity.

You should be ok with the oal and the charges listed for that weight. Shoot a few and examine your case, check your velocity and go from there.
 
Resize a fired case and seat the bullet to 2.5" OAL (base of cartridge to tip of bullet), try to chamber it. If you can't, nudge the bolt back and seat the bullet a little deeper until you can close the bolt with some resistance. Remove the round and measure base to ogive. Insert the dummy back in the rifle, slide it into the chamber and close the bolt fast and hard a few times, until ogive measurement settles down and stays constant. See how that measurement compares to the one you get from your Hornady tool

I haven't loaded for a Sako 223 but the two Tikka 223's I have had fairly long freebore
 
Look at the load data and see what the twist rate is, rifles with a twist rate 1in12 or 1in14 will have a short throat of .0250. And rifles with a 1in9 twist will have longer throat and can be loaded "warmer". The throat in my Savage .223 with a 1in9 twist is longer than my AR15 rifles, .0500 vs .0566. All reloading data is ball park and you are told to start at the suggested start load and work up. The Sierra manual does not list 77 grain bullet in their bolt action data and is only in the AR15 load data. Below you can see throat length and throat diameter that will effect start pressure

wjAOlWq.jpg
 
The lyman book states 1in12 rate my rifle is 1in8 twist. I have not fired the gun yet, so maybe I'll grab a box and shoot a few rounds to get some fired brass. I just took measurements with 80g SMK got 2.370 for COAL Lyman manual states 2.550 for 80g SMK I also tried a Hornady 75g Match bullet got 1.828 for CBTO and 2.220 for COAL book states 2.390 It seems strange doesn't it? or is it just the way this rifle is. I'm just afraid of the high pressures seating the bullets that far below specs.
 
you'll need to reduce the powder charge when deep seating a bullet in a short throated rifle. .010" jump to lands is very close

What powders do you have on hand?
 
The only differences are the throat lengths, meaning the short throats will have to have the heavy bullets seated deeper.

And your rifle has a 1in8 twist with a longer throat and your bullets can be seated further out.

Quickload has three different loading sections for the .223 and 5.56 just because of the different throat lengths.

Below, military loads for the AR15 with its longer throat for comparison.

HCX23La.jpg
 
bigedp51 said:
Quickload has three different loading sections for the .223 and 5.56 just because of the different throat lengths.
Click to expand...

All 3 listings 223 Rem, 223 Rem (SAAMI), and .223 Rem. (NATEC PCA Polymer Case), all share the same default OAL of 2.260" OAL.
 
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