What do you actually size your 223 cases to?

[Unique Username]

223 bolt rifle used in modified type bench shooting. With the Hornady comparator I size my brass to 1.461" - 1.462".. I also trim back cases to 1.755" and run them out to the max of 1.760".. Before sizing they are coming out of this rifle at 1.463"

That. That’s what I was looking for. Your fired cases are coming out 002 larger than mine. (1.463 vs. 1.461 ) Granted, out of a bolt gun, but it’s the numbers I’m curious about. Fired brass vs. sized in other people’s rifles. Would there be a pattern? If in theory all chambers are within 1/100” of each other, the ability to truly fireform a case at the speeds a semi auto cycles as opposed to the completely controlled environment in the chamber of a bolt gun? If bolt guns fired cases were always trending larger than semi auto cases, then it could mean semi autos aren’t really fire forming to the chamber and the cases are being sized way too short based on false numbers.
I dunno….. maybe I just need to get out more. lol

 

[Varminterror]

That’s what I was looking for. Your fired cases are coming out 002 larger than mine.

Be careful with this assumption - you are falling for a potential trap. You are assuming that both of your Hornady comparators (remember, it is a COMPARATOR, not a gauge) will engage the brass the same way for both of you, with two different calipers (of unknown quality or condition or calibration state) in the hands of two different reloaders using two different rifle chambers… it’s pretty easy to trick your Comparator by 0.001 just by a little difference in thumb pressure.

Also keeping in mind, while we tend to assume that our fired brass comes out of the rifle as a perfect mold of the chamber, that’s often not the case. It’s not uncommon that rifles won’t close again on fired brass, which for various reasons means that the brass has grown larger than the actual chamber. It’s also not uncommon that rifles would freely close on brass, meaning the brass hasn’t fully fireformed to match the chamber, and may have still over 0.001” headspace clearance (pretty common, as evidenced by the misguided process of neck-only sizing - where the brass repeatedly fits back into the chamber until it eventually grows with repeated firings to the point it no longer fits).

If in theory all chambers are within 1/100” of each other

They aren’t, not even in theory.

A Forster Go gauge for 223 Remington SHOULD measure at 1.4636”, while, for example, a No-Go from Forster will measure 1.467”, meaning this would allow up to 2.4 thousandths difference… and again,

maybe I just need to get out more.

Largely this - just get out of the weeds so you can see the forest for the trees. Comparators are comparators, nothing more, nothing less. The moment you change calipers, change individual comparator bushings, or change the reloader using them (or even change the day the same reloader uses it, for some folks), you’re breaking the system - the measurements aren’t actually transferable.

 

[kmw1954]

I have to agree here in many ways.
I put this barrel on this action and set it with headspace go-no go gauges. It certainly could have been different depending on just where I finally set the barrel. Could have been longer of shorter.

Also in the mist of developing a new rifle. Here I have at the moments 4 different bullets I want to try. Two are the same weight but different profiles. Here I did an overall bullet seating test using the barrel and the bolt and come up with a measurement using my comparator. I have done this test many times before and found it accurate but time consuming. So while waiting to do this and while ordering the bullets I added in a Hornady OAL Gauge and a Modified case to try out.

Yesterday evening I had time to test these new tools and I will tell everyone, the two measurements were not even close! The Hornady gauge was consistently shorter. Next I compared the Hornady modified case to my fired case and it measured .097" shorter using the same tools. Now I wish I knew someone close by with a lathe to turn a fired case for me.

 

[Unique Username]

Be careful with this assumption - you are falling for a potential trap. You are assuming that both of your Hornady comparators (remember, it is a COMPARATOR, not a gauge) will engage the brass the same way for both of you, with two different calipers (of unknown quality or condition or calibration state) in the hands of two different reloaders using two different rifle chambers… it’s pretty easy to trick your Comparator by 0.001 just by a little difference in thumb pressure.

…… well, heck. You’re totally right about that, aren’t you. I didn’t think about that. Way to deflate my my ( self-described ) moment of brilliance, pal ! lol
But you saved me from needlessly burning additional brain cells, so thank you

 

[Unique Username]

If in theory all chambers are within 1/100”

They aren’t, not even in theory.

I was basing this on SAAMI maximum and minimum chamber dimensions.
( 1.4736 / 1.4636 )

 

[Walkalong]

If in theory all chambers are within 1/100” of each other

I'm assuming you mean 1/1000, because 1/100 is quite large in the world of headspace/head clearance, but even then, it isn't something you can count on in factory barrels.

 

[Unique Username]

I'm assuming you mean 1/1000, because 1/100 is quite large in the world of headspace/head clearance, but even then, it isn't something you can count on in factory barrels.

Wait…… are you trying to gaslight me? Now I’ll admit me and math have never seen eye-to-eye, but isn’t 1.4736 and 1.4636 a 1/100” difference lol?

 

[Varminterror]

That’s my bad - I read 1/100 as 1/1000.

But yes - 1/100” is a mile when it comes to the scale of chamber headspace differences or ammunition-to-chamber fitment… and yes, 1/100” difference is generally considered the bounds of acceptable for 223 Rem.