What is the inside neck dimension on a properly sized .223?

[armoredman]

I'm measuring about .2175 on my brass after sizing, with my cheap Frankford Arsenal calipers. Is that right??

 

[Walkalong]

I would expect about .003 to .004 under bullet diameter before seating. Less is enough for bolt guns. That said, I have never measured any. Maybe some folks have some sized, or will size some, .223 cases.

I am assuming a FL die with an expander button.

 

[hdwhit]

I get 0.2195 to 0.2200 with my cheap digital caliper.

Using my old pre-dial, pre-digital vernier calipers, I get 0.220 pretty consistently.

The expander ball on my RCBS .223 dies (as well as the one on my 5.7mm Johnson dies which anticipate a .224 bullet) both come in at .2230 on my micrometer.

 

[243winxb]

2 RCBS FL dies. Expanders measure .222" on each.

Bolt gun die, honed neck. ID .222" LC brass, running an annealing test on it. 2nd anneal, 3 loading.

Federal brass , unknow loadings , die as it came from RCBS . ID .220"

Measured with an RCBS dial vernier caliper.

 

[armoredman]

Hmm, sounds like the expander ball is about right, then, maybe a little small. The primer pocket swaging die has an anvil that resizes the inside neck to .224, which I would say is a bit too large.

 

[cfullgraf]

You will not get a good inside measurement of the case necks with calipers. The flat on the jaws of the caliper do not conform to the curvature of the case mouth. The measurement will always be a bit small.

 

[armoredman]

I lack an inside mike, however. Best I can do, but thank you, might be what I needed to know.

 

[hdwhit]

cfullgraf wrote:
The flat on the jaws of the caliper do not conform to the curvature of the case mouth.

Are you referring to the lip that can occur at the case mouth as a result of being resized or are you suggesting that the neck of the 223 case is curved/tapered?

If the latter, it is a simple matter to ream the inside of the case neck for 1/10 inch or so, thereby removing the lip and exposing the actual neck to measurement. In that case, the measurement still comes back at 0.220

 

[stringnut]

You will not get a good inside measurement of the case necks with calipers. The flat on the jaws of the caliper do not conform to the curvature of the case mouth. The measurement will always be a bit small.

Right on that. To measure inside a case neck you would use t gauges or something similar. Some calipers have rounded edges for measuring inside. You can measure different brass with the same calipers for a comparison. However, due to manufacturing tolerances of the calipers, as soon as you use a different caliper you may get different readings.

 

[edwardware]

I lack an inside mike, however. Best I can do, but thank you, might be what I needed to know.

I typically measure neck thickness with a ball anvil mic, and outside neck with a flat anvil mic or calipers.

You can also measure your expander ball, then measure the neck with the expander ball inserted, then the neck without it inserted. You'll know both the final inside diameter, and the springback, and you only need the tools you have.

 

[Walkalong]

You can buy pin gauges individually. And yes, the case mouth must not have any ridges etc. A chamfer tool can usually fix that enough to get a good measurement. Even with an inside mic, it's tough to measure to the nearest .0001. I can do about +/- .0002 on a poor day and about +/- .0001 on a good day, getting it exactly right on occasion. .0001 is real tiny, and barely any pressure on the mic.

 

[Sunray]

The brand or price of a vernier makes no difference. There's no right or wrong after sizing dimension either. Don't over think the whole thing.

 

[Walkalong]

There's no right or wrong after sizing dimension either. Don't over think the whole thing.

Ditto on don't over think, but yes, the case neck ID can be too large, as well as too small. One won't give any neck tension (Or bullet pull if you wish), and one will over work the neck, be too tight, can cause seating/concentricity issues.

But within reason, yea, don't worry too much about it for general use ammo.

 

[1stmarine]

hummm... Think about the way we measure. Calipers can be misleading.
I am not sure if this is worthy for you but try a micrometer vs. calipers and take deltas after annealing and sizing if you want.

If you want to control neck tension you can use Redding type S-bushing will give you the control and I think also forster will hone the neck to your
specs if that is what you want and for little money.

I don't use them for the 223 but in the 6mm and others I have a buttons of different sizes.
It also depends on the case and the diameter and construction of the bullet so better check on the spreads if you want fine tuning.
I think .2220 to 2225 is in the bulk park. But again bullets are also different that is where one should start for that kind of fine tuning.
Some bulk deals bullets are not that consistent but perhaps is not also the type of bullet where one is going to worry too much about
consistent neck tension.

If you are worried about starting pressure a good consistent crimp has also a lot to do with it.
In fact is another way to achieve good consistent starting pressure even in bullets w/o cannelure but with the caveat that one has to do it
so slightly and also how we chamfer the brass at the risk of damaging the bullet that should be avoided.

It is all about the dancing the consistency tango and that unfortunately sometimes involves neck turning and or reaming, annealing and all that
depending on the brass source. Some folks make great ammo using "free" military brass from all over and some simply go and buy quality
brass like lapua. It all depends on the goals and the time you have.

 

[armoredman]

So, to make things easy I have ten round i made up using the "oversized" neck milspec brass, and the bullets, .224 sized generic FMJ, and most of them slipped VERY easy into the neck, but none of them moved with finger pressure after seating. All were then given the usual light FCD treatment. I loaded a few bullets into UNprimed UNcharged cases that had been "reamed". COAL was measured at 2.239. They were loaded into the BREN 805 and ejected, albiet only under hand or released bolt power, hand cycled only. Interestingly enough, as measured again on my cheap clipers, they both appeared to have the bullet move forward maybe 1 thousandth of an inch on the first cycle only. Further cycling produced no bullet movement forward or backward I was going to test fire them today, but some issues arose that kept me from the range.
What does all this mean? Probably, for me, not a dadgum thing, but knowledge is never wasted. I think that I am ,indeed, over thinking this, and will continue to use the item as delivered. We'll see on the firing line as I fire two differnt loads whether or not it has any measurable effects on accuracy or cycling. I'm willing to bet it wont, considering the BREN isn't a target rifle, and I don't shoot benchrest.
Thank you to everyone for your assistance and a thank you to those with helpful commentary, much appreciated.

 

[243winxb]

So, this is about bullet movement on chambering a round?

Measure a sized neck before and after seating a bullet. After seating, has the neck expanded by .002" or more?

If it has, good to go.

A good read from Sierra http://www.exteriorballistics.com/reloadbasics/gasgunreload.cfm

Bullet pull is 35 pounds minimum.

 

[Walkalong]

most of them slipped VERY easy into the neck, but none of them moved with finger pressure after seating.

Either the sizer is too big in the neck area, or the expander button is too big. Easily tested by leaving the button out and then see what neck tension is. Should be very tight. If it is, polish the expander down some by chucking it up in a drill/drill press/lathe/etc and using 400/600 sandpaper. Polishing it will help make it smoother going through the necks anyway.

 

[armoredman]

It's not the expander in the sizing die - it's the anvil in the crimp swaging die that's the issue. I will get some sandpaper and polish that puppy down.

No, it wasn't about bullet movement about seating a round it was if the anvil on the swaging die was too large, and it appears to be so at this time, so I will file/sand it down until it bypasses the neck and simply supports the case head against the pressure of the swaging die.

 

[Walkalong]

Are you using a Lee collet sizer? Yes, only "fix" is to polish down the mandrel the collet squeezes the neck around.

 

[armoredman]

I'm using a standard Lee Deluxe Die set for the regular loading process and that isn't the one that's the issue - it's the anvil inside the RCBS swaging die set.
https://www.opticsplanet.com/rcbs-primer-pocket-swager-combo-2.html
Perhaps I should just ask RCBS how much for a new mandrel/anvil/swaging rod/whatever the dadgum thing is called.

 

[Walkalong]

So, the RCBS "anvil" for the primer pocket swager is too fat to slide into the sized case mouth without expanding it?

 

[243winxb]

RCBS primer pocket swager. A rod to large in diameter would open the sized necks.

• 2 Swager rods: (Smallest is for 223 only)

 

[armoredman]

Yes, the rod is too wide and opens up sized necks to .224. I think I will try contacting RCBS to see about getting a new one. The large rod is for .308, and REALLY doesn't fit.

 

[Blue68f100]

Normally your doing primer pocket swagging before the brass is sized, part of the brass prep process. I do it while the brass is still dirty, just deprimed. The carbon soot left behind helps lubricates the die so it does not stick.

 

[entropy]

You will not get a good inside measurement of the case necks with calipers. The flat on the jaws of the caliper do not conform to the curvature of the case mouth. The measurement will always be a bit small.

Some have 'knife edge' inside measurement 'blades; those give decent numbers. I get .221 with my General.