Loaded virgin Nosler brass in 270win with a 130 AB 18 mos ago. Measured the OD of the necks of loaded rounds, then ordered a FL sizer from Forster with the neck honed to .004” under (as they suggested). I then use an expander to get back 2 of those 4 thousandths before seating. Recently, I noticed that the difference between the OD of a fired case neck and a sized case neck is .011”.... a buddy says that’s crazy and I shouldn’t be moving brass that much... is he right? What could/should I do differently? Thanks
Excessive?
- Thread starter Jody Simcox
- Start date
Switch to a bushing die.
I would check out Wilson,
Dusty Stevens
Shiner
Nothing you can do about your chamber neck dia. Die has nothing to do with it.
The Redding bushing die FAQ recommends if the unturned necks vary .002 or more to reduce the neck diameter .004 and use the expander. Meaning with a bushing die or the honed neck Forster die the OP has he would still be reducing the neck diameter the same amount. And with a bushing die and his chamber neck diameter a bushing die would induce more neck runout.
Bottom line, with a factory SAMMI chamber and its neck diameter you are better off with the Forster die that would produce a more concentric case.
ED
That's not true at all!!
I own both Forster and Wilson
Forster doesn't hold a candle.
Fogettaboutit!!
The OP measured a loaded round then asked for a .004 reduction honed neck..
Instead he received.011 reduction
Someone made a mistake period..
A F/L bushing type Die would allow the user to simply order a different size bushing and you know it.
The Wilson Die does not have that stupid expander ball for one for another Wilson only resizes case body .002
and allows headspace adjustment by way of threads.
I OWN both Dies
You perhaps work for Forster???
Here's an addendum for you"
Take that expander ball out of your Forster size a neck and you'll quickly find out how much reduction Forster really provides
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no expert, but wouldn't you want to measure a fired cases's neck O.D. and subtract the .004 thou to give the correct neck tension ? Given that the neck thickness is within a "normal" range of thickness, that should be what the op is looking for. If the difference between a fired case's id and the bullet diameter is really alot, then the chamber would be suspect....but please correct me if i am wrong, as i'm still learning at 63......rsbhunter
You can measure wall thickness or a loaded round then subtract the amount you want to reduce to create bullet hold.
Comparing a fired case to a loaded round can assist in determining the chambers neck diameter.
In a loaded round, isn't there already neck tension induced, or was that supposed to read " wall thickness OF a loaded round" but you can't measure neck thickness of a loaded round, can you? I thought the dimension (neck od) of a fired case was supposed to be measured, then the amount of neck tension desired, subtracted...given an allowance for spring back....guess I need to do some more research on the matter...rsbhunter
Response #4 is your answer.
SPJ
Dusty Stevens above is 100% correct, meaning no one has any control of how much the neck expands in the chamber when fired. And the difference between the OPs fired case neck diameter and the neck diameter after sizing is .011. And this .011 is the same as Reddings recommendation for unturned necks with a bushing die and using their expander.
The "FIRED" neck diameter is being reduced .011 with his Forster dies honed neck. And then expanded .002 with the dies expander to push the neck irregularities to the outside of the neck.
And even if the OP neck turned his cases he would end up reducing the "fired" neck diameter even more.
Bushing dies work best with tight neck chambers and neck turned brass. And when you reduce the neck diameter .004 or more with a bushing die it can induce neck runout.
And I do not work for Forster or own Forster stock, but I do get less case neck runout after sizing with Forster FL dies. And this is because of the dies high mounted floating expander and the case neck being held and centered in the neck of the die when the expander enters the case neck.
Below I added a modified Forster high mounted expander assembly to my Redding .243 full length die to greatly reduce case neck runout. And I also have no control of how much the neck expands in any of my factory rifles. And the OP does not have a tight neck chamber and his loaded case neck are expanding approximately .007 to .008 when fired. And then reduced .004 in diameter more than a loaded round and then expanded .002.
That being said you can remove the expander from any make full length die and then use a expander die to reduce neck runout. But with a Forster FL die you can do the same thing in one sizing operation vs using a expander die with the same or less runout.
Bottom line, there is nothing wrong with the OPs Forster custom honed neck diameter.
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From Redding's website: https://www.redding-reloading.com/tech-line-a-tips-faqs/140-bushing-selection
There has been some confusion regarding the correct diameter bushing that should be used with Redding Bushing Style Sizing Dies. The most common misconception is that the bushing diameter is determined by the neck diameter of fired cases or the neck diameter of the chamber that the reloaded ammunition will be fired in. The bushing diameter is related to the chamber neck diameter, but only indirectly, in that the loaded cartridges must have adequate clearance at the neck to allow the bullet to be released properly upon firing.*
The easiest way to determine the proper diameter bushing is to measure the neck diameter of several loaded or dummy cartridges with an accurate micrometer. (These dummy cartridges can be loaded with your old set of dies or a borrowed set.) Then, simply subtract 0.001" from the cartridge that had the smallest average measurement. This will allow for a slight amount of spring back and create a proper press fit for the bullet.
Another method of determining bushing size, is to measure the neck wall thickness of the cartridge cases with a ball type or tubing micrometer. Double this measurement and add the bullet diameter to calculate the neck diameter of a loaded cartridge. As above, subtract 0.001" from this figure to determine bushing size. This method is the least desirable of the two, as a ball micrometer is fairly expensive and more difficult to read consistently than a conventional micrometer.
If you're starting with new cases, the neck wall thickness can be determined as above with a ball micrometer, or you can seat boat-tail bullets in a few cases and measure their neck diameter. Generally, the neck diameter of new cases is small enough to hold a bullet without sizing. As a last resort, you can measure the neck wall thickness of the cases with a caliper. Be aware that you may not select the correct bushing on the first try when using a caliper to measure neck wall thickness, due to the reduced measuring accuracy of the caliper.
The above methods of determining bushing size require that the cases being sized have a fairly uniform neck wall thickness or have been neck turned. If the neck wall thickness varies more than 0.002", it may be necessary to use a bushing a couple of thousandths smaller than your calculations indicate, and then use a size button in the die to determine the final inside neck diameter.
After loading your first few cartridges, it's a good idea to test the grip that the case neck is exerting on the bullet. The simplest method to perform this test is to press the tip of the loaded cartridge against the edge of your reloading bench with moderate pressure. The bullet should not be seated deeper in the case if you have sized at least one caliber of the case neck. If the bullet is seated deeper in the case, switch to the next smaller size bushing and start again.
It has come to our attention through customer calls and our own use of the bushing style sizing dies that in certain instances, a given neck sizing bushing will produce a case neck diameter that can be several thousandths of an inch smaller than the actual diameter of the bushing. This idiosyncrasy occurs when the neck diameter of the fired case is a great deal larger than the diameter of the neck sizing bushing, such as occurs when factory chambers are on the large side of the tolerance range and the brass is on the thin side. Typically, we have not noticed any problems until the case neck is reduced more than 0.008-0.010".
Solutions include, increasing bushing diameter to compensate and/or the use of a size button. Reducing the neck diameter in two smaller steps by using an intermediate diameter bushing will also help. More concentric necks will also result using this method, as the case necks are stressed less during sizing. Don't forget to properly chamfer the inside and outside of the case mouths and apply a light coating of lubricant to the case necks before sizing.
To determine bushing range for standard calibers see "Bushing Range Chart"
If you have any further questions, please feel free to call our technical support line.
* We recommend that the neck diameter of the largest loaded cartridges measure at least 0.002-0.003" smaller than fired cases measured at the same location. This ensures that there is a clearance of at least 0.001-0.0015" all around the neck of the loaded cartridge. This clearance allows the case neck to expand and safely release the bullet upon firing.
Below a very good read on how some dies over work the case necks and why a honed die might be a better choice.
Are Your Sizing Dies Overworking Your Rifle Brass?
http://www.massreloading.com/dies_overworking_brass.html
Are Your Sizing Dies Overworking Your Rifle Brass?
http://www.massreloading.com/dies_overworking_brass.html
The OP measured a loaded round then asked for a .004 reduction honed neck..
Instead he received.011 reduction
Someone made a mistake
Incorrect. My sized necks measure exactly what I asked my die to be honed to.
Dusty and Uncle Ed get it
Instead he received.011 reduction
Someone made a mistake
Incorrect. My sized necks measure exactly what I asked my die to be honed to.
Dusty and Uncle Ed get it
And Jody and Dusty Stevens must be almost as smart, good looking and modest as I am.
I just hope the other Yo-Yos here get it.
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Dusty Stevens
Shiner
I'm still not drinking the Forster or Redding expander ball Koolaid
SPJ
I also do not use the expander ball in my Forster die...I use an expander mandrel .002” under bullet diameter
SPJ
I also do not use the expander ball in my Forster die...I use an expander mandrel .002” under bullet diameter
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