Neck sizing or shoulder bumping

Following instructions on full sizing will work fine and safe in all rifles when all instructions are followed. I only punch paper, so I make adjustments , some good some not so good . Hunting is a different ball game , your rounds have to chamber in all sorts of conditions an shoot fairly accurate . Thanks guys for understanding what I posted .

Some post to show how highly educated they are , that's fine but sometimes it's over my pay grade. I try to keep it simple . The higher ups are there to explain but the have to remember to put it in the simplest terms . I wasn't a chemistry major. Nice talking guys.

Chris
 
In the 40ish years I’ve been reloading, I started with FL sizing. Then I read about partial resizing (neck sizing with my FL die). I switched to that with my 220 Swift and it shot great. Admittedly, the rifle had been set up by a national class gunsmith and a new barrel, so you’d expect it to shoot great. Still, with the tapered case of the 220, I am not sure the case was being resized in any way other than about 2/3 of the neck. Bottom line..it worked great. In later years I tried the Lee Collet Dies, and they worked great, but the cases needed eventual FL sizing, or some degree of FL sizing. I bought Bushing Dies and tried them for a while (they are for sale now). Where I am today is where many folks are. I FL size to the degree to set the shoulder back a touch (a touch being an itty bitty bit). I refer to that approach as “Partial Full Length Resizing”. It puts each case back to the desired size for my rifle. The old style Partial Resizing didn’t do that, nor did the Lee Collet Die, unless you set the shoulder back with a Body Die (which works fine).
 
603Country
I also tried partial neck sizing , found full length sizing using the Redding Competition shellholder set of 5 worked great , the die is set up to make full contact to the shellholder at the same time sizing the entire neck with minimum headspace ( bolt face to datum line ) the shell holders have different deck heights each .002 lower. Also went with the Redding full & neck S Type bushing dies . They have been in the green box for two years now . Using the standard RCBS full length sizing die , nothing fancy , and its been working great for me . Be Well.

Chris
 
Here's my process, for what's worth.

Rifle - Tikka T3 Tactical in 308

Brass - all the same headstamp

After a range trip

Deprime and Neck size using Redding competition die

Check for chamber fit and ease of bolt closing (several rounds)
, if bolt closes easily, finish the rest of the batch, clean and reload.

After subsequent firings, if the bolt begins to require additional effort to close, that batch of brass will be annealed and then neck sized and run through the Redding Body Die. Again chamber checking several to insure proper fit to my rifle. Then clean and reload.

I find that this works the brass as little as possible and it works for me. YMMV

I also like the fact that neck sizing requires far less if any lube as opposed to full length sizing.
 
I believe partial sizing and FL sizing are the same thing it's just that partial sizing fit's the case better to your particular chamber. The entire case is sized when you partial size but the distance to the shoulder may change a bit. No two chambers are exactly the same. A reamer wears as it's used but used again so long as the finish job meets SAMMI spec's. I know this to be true as I have two 243's and both have their own set of dies that stay partial set for that particular chamber. One chamber is just enough bigger than the other to not let the other rifle chamber the round while reloads from the other rifle chamber in both. But I strongly suspect that both chamber's meet spec's. The idea behind the FL die seem's to be to resize any case so that it will fit in any chamber it's made for. They pretty much do that! Partial sizing still FL sizes but fit's the finished case to a particular chamber. It may or may not fit in another chamber.
 
The reason cases don't have headspace is there is normally no reason to put another case's head inside of them as part of the loading process. A chamber does have headspace because a chamber does need to accommodate a case head.

Where I believe the confusion started is when the RCBS Precision Mic and the Stoney Point case comparators came out they told people they were for measuring headspace but directly measured a case. The idea was that a fireformed case would mirror the dimensions inside the chamber well enough that it could be used as a gauge to transfer those dimensions for indirect measurement by these tools. Not surprisingly, this is called a transfer measurement, and the intent was to measure the chamber indirectly to learn the chamber's headspace and then to use the comparator to determine when you had resized a case enough to fit that chamber. It is just that people didn't understand the fireformed case was a transfer gauge, taking the measurement of the fired case to be a direct headspace measurement because they didn't understand what headspace was. Now that confusion seems to be inextricably embedded in the lingo.


603 Country,

I've been using a Redding body die to get the shoulder where I want it and the diameter back for easy fit and the Lee Collet Die for the neck. It makes for very straight brass with minimal eccentricity. An extra step, but I like that the Lee Collet Die mandrel prevents an interior donut ring at the neck and shoulder junction from building up.


Don Fisher,

I think it might be helpful at this point in the discussion to draw a clear distinction between partial FL resizing and partial neck sizing. The former is like bump sizing, using an FL die to size both the neck and the body, but not driving the body into it any further than is necessary to get the fit we want. The latter uses either an FL die or a neck-sizing-only die short of full insertion of the case into the die, leaving a short portion of the neck unresized near its junction with the shoulder. The idea is to have the remaining short expanded length of neck help center the bullet in the chamber aligned with the throat.
 
Unclenick
I used a Go Gage 308 Cal. 1.630 to find Chamber length , by adding shims to the bolt face my chamber measured 1.632 . My cases when fired get shorter from expansion . I full size using the RCBS Standard full length sizing die with the Redding Competition shellholder set of 5 to completely size the case and neck to 1.6305 using the RCBS Precision Mic to check measurement. Getting back to the word headspace , were talking about the space from the bolt face to the back of the case that is left " wiggle room " headspace sounds better , would you agree. It is the space between the head .
 
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Unclenick, I had remembered that you did the case sizing “two step”, with the Redding Body Die and the Lee Collet Die. I know of a couple other serious shooters that do that also. I considered doing it that way, but with the very accurate rifles I have and the good brass, I can get all the accuracy that I need for my purposes by just the Partial FL Sizing.
 
I take a different approach. I mount my barrels myself have GO and NO GO gages. When a fired case comes out it is .002 longer at the shoulder than it went in so when setting the FL die I compare the sized case to the Go gage. Seems to work well enough. Cases chamber easily and I get 10+ reloads from them
 
Ditto other than I accept whatever the head-space of my Mil Surplus rifles (or Civie models I have or have owned) and do the minimum resized that gets me a .003 push back on the shoulder.

I refer to this as minimum shoulder bump back as its understood though I am happy to add its done with an FL die (Full Length) or Full Length resizing die to be correct)

Said check is done with a Hornady micrometer tool, a modified bullet Ogive adapter from that base unit. This gives me a unique measurement not shared if the case shoulder adapter is bought but then I don't care, its mine, I built (modified it from a bullet Ogivie adaptor) , I think its cool and I don't give out the measurement as its irrelevant to anyone else anyway)

Doing so I have fired cases as many as 20 x with no cracks in the base.
 
For me this breaks down into real vs non real.

Yes, in referring to a a case as head space is not technically correct.

The reality is that head space, the cartridge are so directly interrelated as to be virtually the same (with some miner variance on the state of not fired and fired)

So, If I tell you I saw a really big dozer pushing the snow pile, does anyone really not know that I am talking about a piece of machinery that is technically known as a continuous track laying tractor with a large metal plate in front ala Bull dozer , Caterpillar etc.?

Yes there is a time and a place for purely technically correct terms. I don't think this is it.

The test being that if the average reloader understands what is being asked or said about it then it should be accepted.

I work in a very technical world and I know when I have to use correct terminology and when I get a blank stare from a manager who does not care what I call it as long as I can tell him what the problem is and what needs to be done to remedy it.
 
For me this breaks down into real vs non real.

The reality is that head space, the cartridge are so directly interrelated as to be virtually the same (with some miner variance on the state of not fired and fired)
Click to expand...

For me this breaks down into real vs non real.
Click to expand...

Or fact from fiction, and then there is truth from BS.

The chamber has head space, the case does not have head space but if somehow a reloader could stumble on a difference in length between the chamber from the shoulder/datum to the bolt face and the length of the case from the shoulder/datum to the case head he could claim he discovered clearance.

After the discovery of clearance he could determine where the clearance was located as in between the shoulder of the case and the shoulder of the chamber; OR between the case head and bolt face.

F. Guffey
 
Well long ago I found that if it flies like a duck, quacks like a duck, has webbed feet, duct bill and has duck DNA, then its a duck.

Having read about Moses, it seems to me that if he had asked directions from someone he might not have wandered in the Wilderness for 40 years.
 
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Headspace is literally the space you fit a case head into (along with other case parts these days). Nothing more nor less.

It's common vernacular to call a semi-automatic rifle an "assault rifle", but I'm a Luddite and prefer the original military definition to Senator Feinstein's. (I can't recall who it was said to beware the government's purposes when it changes the meaning of words. Maybe George Orwell.) In any event, I think, for the sake of communication, it is generally beneficial to stick to definitions people can look up, wherever possible.
 
Unclenick
As always your explanation of heatdspace makes perfect sense to me . Just bare with me for still using headspace in sizing , you all know what I mean . Nothing to do with brass but I'm thick headed.

Chris
 
Well, maybe. You can lookup headspace in the SAAMI glossary where it is defined as:
"The distance from the face of the closed breech of a firearm to the surface in the chamber on which the cartridge case seats."​

But the tool name-induced misuse of the term as a case dimension is not there. So you can appreciate that a newbie reading a thread that includes the misuse assuming we are all privy to the secret code might look the term up and come away with nothing but confusion.
 
But the tool name-induced misuse of the term as a case dimension is not there.
Click to expand...

I suggest measure before and again after, I suggest the reloader learn to zero a gage, and I understand that locks many reloaders up. I insist the case does not have head space and I understand many reloaders refuse to accept that because they have insisted most of their reloading life the case has head space.

The case: The case does not have head space, the case has a length that is determined by a datum. When measured from the datum to the head of the case a reloader should be able to determine the length of the case from the datum to the case head. In the real world the case has a minimum length; if we were talking about the 30/06 case the minimum length of the case would be .005" shorter than a go gage when the gage is measured from the datum to the case end of the gage.

I have dealt with all lengths of chambers; some short, some long and others that were within thousandths of being correct for SAAMI etc. This stuff does not make me nervous, my dies and presses have threads, threads allow me to adjust the length of my cases from the datum/shoulder to the case head.

There is no riddle, I can fire minimum length 30/06 ammo in my long chambered 30/06 rifle or I can form cases to fit by increasing the length of the case between the datum of the case to the cases head .014"; no one ever ask why .014" if the chamber is .002" longer than a field reject length chamber. I am the reloader that includes clearance.

And then there is that other factor that locks reloaders up; if the chamber is .002" longer than a field reject length chamber why doesn't the case have case head separation when fired with minimum length/full length sized ammo?

F. Guffey
 
how to provoke a reloader to think?

Again: I suggest reloaders go out and purchase R. Lee's book on modern reloading. R. Lee list the minimum length of cases in his drawings. And? No one ask about head space as it applies to the chamber? .005" + the minimum length for a 30/06 case for any chamber that used the 30/06 case as a parent case. EXCEPT when the case was shortened from the shoulder/datum to the case head.

I know, there is SAAMI, problem with SAAMI and reloaders? Tolerances and variations and then there are those +/- eses:), relloaders just can not handle them.

F. Guffey
 
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