Hornady Headspace Comparator Measurment Questions

[PigPknHeat]

Long story short I bought a new Hornady 223 sizing die today because I mangled the lee pacesetter I had that got a case stuck in it.

After sizing a few rounds I compared them to the other sized cases I was working on with the Lee die and the Headspace comparator measurements were quite different. Both gauges were set up per the instructions with no additional adjustments. The Lee sized cases came in at 1.451" +/- .001" and the Hornady sized case came in at 1.457" +/- .001".

Question 1: Is that normal for that much variance between brands? Anyone think the Lee measurement is too small?

Question 2: For the standard Hornady sizing die the instructions say to raise or back out the die a bit to set the shoulder back less. If that is done will the case not be fully sized and case feed issues in a semi?

Question 3: Should I be aiming for a measurement only a few thousands back from the fired case measurement even if this is for a semi?

For reference the once fired case measurement came in at 1.463" +/- .001"

Thanks everyone, the more I get into this the more I realize I need to make it to one of EC's Classes.

 

[NavelOfficer]

Haven't used the Hornady system, but I wouldn't think .005" to .010" variance would prevent your brass from chambering. If you are getting resistance upon closing the bolt, I'd say bump the shoulder a tad further, but don't be misled into thinking that it is merely a shoulder issue. Be sure your sizing step is proper before going into mass production; you can make a dummy round with your resized brass and see how it chambers.
There are no doubt variations in tolerances between brands of dies, but I've used assorted brands and haven't really found any that won't fulfill the purpose they are made for.
Any case that has a properly-positioned shoulder may not be ready for use in all chambers.
You'll often find that fired cases may chamber in your firearm or will drop into a headspace case gauge just fine. I use the L.E. Wilson variety and can't speak to Lyman or Sheridan brands. A neck-sized only case will slip in as advertised, but since the NS die doesn't size the case body (diameter) it will usually bind up while chambering in an AR or other autoloader. Once you have your shoulder dimensions down pat, don't overlook checking the case diameters at several points to make sure your sizer die is restoring the brass to SAAMI specs (assuming that's your objective). This will help assure that your reloads will chamber in any firearm designed for SAAMI-spec ammo.

 

[EddieCoyle]

http://massreloading.com/bottleneck_case_resizing.html

 

[ruebarb]

Take EC's class. The comparator is just that, compares supposedly similar cases, the rcbs mic, gives exact measurements compared to saami. They will both get you there, i prefer having actual measurements.

As you found out just srewing in some sizing die, you have no idea what shoulder you are getting. Different brass will result in a different shoulder also, depending on the rifle it was fired from last.
Adjust the die until you get the shoulder you want.

 

[mac1911]

For what it's worth I became really confused for a while after getting one of the hornady comparator.
Take the time to slow down. Re set your dies.
Also I have found differences between manufactures.
My Lee die set for 223 will actually push the shoulder forward if you try to minimize shoulder set back.
Basically I have to set the Lee die to set back .005" or the shoulder seems to bump out.
My hornady new dimensions is more precise? As in if I set the die up as directed it seems to be darn close.
Most of my loading is for M1 and AR so I set back .003-.005" and all is well.

 

[jasons]

Question 1: Is that normal for that much variance between brands? Anyone think the Lee measurement is too small?

I wouldn't worry much about that, the important thing is the shoulder difference between fired cases and what you resize them too. Use the same tool to measure before and after and don't worry about the overall number so much as whatever the difference in base to shoulder length is.

Question 2: For the standard Hornady sizing die the instructions say to raise or back out the die a bit to set the shoulder back less. If that is done will the case not be fully sized and case feed issues in a semi?

I don't use any Hornady rifle dies, but generally speaking you should be fine. Any decent FLS die should have plenty of leeway to adjust the shoulder bump and still sufficiently size the base.

Question 3: Should I be aiming for a measurement only a few thousands back from the fired case measurement even if this is for a semi?

I always look to bump the shoulder back .002" from what that particular rifle spits out. (Give or take .001" or less.) I've never had any problems feeding or extracting with this method and brass life and accuracy has been good for me. That assumes that you're loading for one particular rifle - if you're loading the same brass for multiple rifles you'll need to go to the least common denominator (probably SAAMI max) but you'll sacrifice some accuracy and brass life.