Nosler .223 Brass Shoulder Measurement Question

[GunnyUSMC]

I am trying some Nosler Premium brass for the first time in my .223 bolt gun. I measured the shoulder new at 1.4145. After firing that brass (1st firing), I measured the shoulder again expecting to grow slightly but the shoulder did not move at all. I was pretty surprised because the load was a little hot.

I am using the LEWilson .223 FL Busing die, and a Zero press with their zero modular shell holder system and using the +8 bushing (they come with a 0, +2, +4, +, 6, +8) which conceptually would not bump the shoulder at all. After FL resizing, the shoulder was pushed back .002.

This not what I was expecting at all.

Any thoughts

 

[SeabeeKen]

Gunny, Last year shooting 223 in UBR I had to change to Nosler brass suddenly. Virgin brass but I did the usual prep. Same thing happened. I neck sized for 5 firings before seeing any shoulder movement and then only a few at a time. It took 8 firings before all tightened up enough in the chamber to need a bump. Cant explain it but the measurements didn't lie, but it was a first for me. I shot 1 perfect score and place in the top 3 every match with neck sized brass. I suggest neck sizing only until they all grow.

EOCS {SCW} Semper Fi

 

[L.Sherm]

After FL resizing, the shoulder was pushed back .002.

Are your .002 measurements fired vrs unfired just using comparator? You may not be bumping. 002 off of just a fired case expecting no resistance.
Eric Cortina on one of his videos has to bump .004 to get that and ive found the same, .005 on a 20VT.
Try the Wheeler method and compare. My guess is you will have to bump little more to get little or no resistance.

 

[sfinn1]

The first thing you should do is acquire a .223 Go Gage. First try it in your rifle. It will most likely go. Now measure the gage with your caliper with Hornady headspace gage or equivalent. That's your baseline. Now check your new brass, then your fired brass. I believe the brass manufactures size their brass slightly under, say a thou. or so to fit tight chambers. Sounds like your chamber is a "tight one" at minimum spec.

 

[GunnyUSMC]

Gunny, Last year shooting 223 in UBR I had to change to Nosler brass suddenly. Virgin brass but I did the usual prep. Same thing happened. I neck sized for 5 firings before seeing any shoulder movement and then only a few at a time. It took 8 firings before all tightened up enough in the chamber to need a bump. Cant explain it but the measurements didn't lie, but it was a first for me. I shot 1 perfect score and place in the top 3 every match with neck sized brass. I suggest neck sizing only until they all grow.

EOCS {SCW} Semper Fi

Thanks and totally agree. this is the first time i ever fired new brass where there was no shoulder movement.

My second issue is that when using the zero modular shell holder system with the +8 should have the same effect as adjusting the die out far enough so as to only size the neck and not bump the shoulder.... but the shoulder was indeed bumped. I have a redding FL die and will try that to see if the same thing happens. If that doesnt work, I will have to adjust the FL sizing die in the press so i am only sizing the neck.

Are your .002 measurements fired vrs unfired just using comparator? You may not be bumping. 002 off of just a fired case expecting no resistance.
Eric Cortina on one of his videos has to bump .004 to get that and ive found the same, .005 on a 20VT.
Try the Wheeler method and compare. My guess is you will have to bump little more to get little or no resistance.

Yes, i am using a comparator. I measured the shoulder for new brass, then measured the shoulder after first firing and checked chamber fit. Both measurements were the same and chambered the same. I still need to take the step of breaking down my bolt and checking for resistance. To be honest, this will be the first time i have disassembled the bolt (it is a Zermatt Arms Origin action) and I am waiting on my bolt disassembly tool to arrive in the mail. Once i am able, i will be further testing for resistance. However, I was not planning to worry about that until i could get my brass to expand in my chamber beyond the factory dimensions.

 

[GunnyUSMC]

The first thing you should do is acquire a .223 Go Gage. First try it in your rifle. It will most likely go. Now measure the gage with your caliper with Hornady headspace gage or equivalent. That's your baseline. Now check your new brass, then your fired brass. I believe the brass manufactures size their brass slightly under, say a thou. or so to fit tight chambers. Sounds like your chamber is a "tight one" at minimum spec.

Hmmm... that is interesting. Never thought about measuring my go gauge and comparing that to the brass measurements. I have a go and no-go gauge for .223 so will definitely test that.

 

[GunnyUSMC]

The first thing you should do is acquire a .223 Go Gage. First try it in your rifle. It will most likely go. Now measure the gage with your caliper with Hornady headspace gage or equivalent. That's your baseline. Now check your new brass, then your fired brass. I believe the brass manufactures size their brass slightly under, say a thou. or so to fit tight chambers. Sounds like your chamber is a "tight one" at minimum spec.

Sfinn1, this has been extremely helpful.

So, a little background... This was the first bolt gun I put together and was a budget build just to do it and have a good training gun. I am using a Zermatt Arms Origin action with a 28" Criterion bull barrel barrel-nut prefit chambered in .223 Rem using the .223 Rem Match reamer. I used both the Go and No-Go gauge when fitting the barrel. My daughter has since begun using it as a starting point for F-Class FTR. She just completed her personal best using this build with a 592 24x at 800yds. Bottom line is that this a really good shooter.

Following your suggestion, I measured both the Go and No-Go gauges. The Go gauge measured in at 1.4140 and No-Go gauge measured in at 1.4160. My new and fired brass measured in at 1.4145.

With this information, are you saying that 1.4140 is my baseline and that I should target .0001-.002 below that number as my shoulder setback?

Thanks

 

[sfinn1]

Gunny, I have no experience with prefit barrels. But in my opinion it was installed with the Go Gage close to minimum headspace. My understanding is the Go Gage is used but the barrel is backed off slightly to increase the headspace. Others should chime in on this but I would take the Go Gage, clean the face off with alcohol, then apply scotch tape and trim the excess off. This should give you another 1 1/2 thou. or so headspace. This is a technique gunsmiths can use when installing barrels. Heavier (thicker) tape can be used if you wish to have more headspace. Ideally with the couple thou. longer chamber from your Go Gage, you can use the Go Gage measurement to size to. That Go Gage is your baseline for sizing.

 

[sfinn1]

Gunny, oh by the way, measure with your comparator the Go Gage with tape added to determine the added headspace.

 

[fkimble@charter.net]

Load and fire a couple cases 3 times , neck sizing only. Now without resizing, measure your shoulder. Take that measurement and subtract .002 to .003. This new number would be your setback measurement. As long as you are using reloads you are golden! If you want to use factory ammo, then you will need to reset barrel so the go goes and the no go either doesn't go or has drag/resistance.

Frank

 

[K22]

I am probably missing something, not unusual with my aged brain but I having difficulty understanding the problem.

The only reason cases are resized is so that they will chamber flawlessly, and they will hold the bullet.

In my experience with bolt rifles, virgin cases may not and often do not expand to the point that the shoulder needs bumped. I often go 8 or so reloads before I have to set back the shoulder. I F/L size every time but at a zero to .001 bump and I have no problem chambering cases. I believe this is because the F/L die is sizing the radial dimension of the case and often, that is all that is needed. This why I do not like a neck sizing die, it does not touch the radial dimension.

When using a comparator, you are measuring on a datum line to assess case expansion. This is not the same as measuring the rifle head space. The comparator measurement is for reference only to compare the fired case to the sized case to assess the amount of expansion.

If the reloads chamber without issue which they should when F/L sizing without bumping, then there should not be a functionality problem. This assumes that the reloads are not loaded to excessive pressure limits.

 

[L.Sherm]

I would leave the haedspace were it is and size your brass to 1.412 or 1.411 even the new brass as long as your FL dies will do it.
Try 1 piece ar 1.412 and see how the bolt closes.

 

[LCazador]

Sfinn1, this has been extremely helpful.

So, a little background... This was the first bolt gun I put together and was a budget build just to do it and have a good training gun. I am using a Zermatt Arms Origin action with a 28" Criterion bull barrel barrel-nut prefit chambered in .223 Rem using the .223 Rem Match reamer. I used both the Go and No-Go gauge when fitting the barrel. My daughter has since begun using it as a starting point for F-Class FTR. She just completed her personal best using this build with a 592 24x at 800yds. Bottom line is that this a really good shooter.

Following your suggestion, I measured both the Go and No-Go gauges. The Go gauge measured in at 1.4140 and No-Go gauge measured in at 1.4160. My new and fired brass measured in at 1.4145.

With this information, are you saying that 1.4140 is my baseline and that I should target .0001-.002 below that number as my shoulder setback?

Thanks

So yes your target number is 1.4140". Best to resize to .002"-.003" shoulder set back. In my opinion if you don't start with this amount of set back so brass can flow forward you will enlarge the rear of the case and wind up with clickers. Especially if you have a maximum or near maximum load. I would encourage you to take note of the head diameter that your started with and keep in mind that no more than .0008" head expansion is acceptable. Once you go past that head dimension, you're open to clickers, primer pocket leakage, etc.

 

[LCazador]

So yes your target number is 1.4140". Best to resize to .002"-.003" shoulder set back. In my opinion if you don't start with this amount of set back so brass can flow forward you will enlarge the rear of the case and wind up with clickers. Especially if you have a maximum or near maximum load. I would encourage you to take note of the head diameter that your started with and keep in mind that no more than .0008" head expansion is acceptable. Once you go past that head dimension, you're open to clickers, primer pocket leakage, etc.

What LSHERM above says with new brass too!

 

[GunnyUSMC]

Thanks for all the really good responses. I have some testing to do.

While this issue was initially focused on my .223 loads, it is going to help me in refining my other calibers.

I will follow-up when i am able to get more data