Running a case through a body die increases headspace -- why?

[nhm16]

I ran some once and twice fired 6mm Rem. cases all the waythrough a Redding body die, and the headspace actually increased. Same when I ran some cases through an RCBS FL die with the stem removed (I neck size with a Lee collet die). The resultant case is harder to chamber than before it was resized.

Does this mean I have a short chamber, and what should I do when I need to push the shoulder back or full-length resize? Since this is a Savage, should I remove and re-headspace the barrel, or grind down the body die (which seems like an extreme solution)?

 

[mikecr]

Is this fire-formed brass?
Sounds like alot of body sizing with less than matched dies. Brass squished inward one direction is going outward another.

I wonder if the condition would clear if you backed off the die a touch.
With a 223 I'm using a standard Redding body die. I trial & error screwing it down, sizing, measuring HS. At a certain point I see HS drop, but if I keep screwing the die down, HS will grow to a point worse than started.
So I locked the die ring right in a window that works.
I could send it to JLC Precision with a few pieces of fire-formed brass for resolution. But in this case I'm alright with it.

 

[jo191145]

What your seeing is quite normal with factory chambers and off the shelf dies.
As the brass of the body is constricted it pushes the shoulders forward.

As you surmised you need to get the die just a touch deeper to bump the shoulders.
Have you tried screwing the die in even further? Just touching the shellholder is'nt the end of adjustment with most presses. Theres plenty of mechanical slop to take up.

If screwing the die in further won't correct the problem a quick fix is stoning down the top of the shellholder. Most of my shellholders have been ground down.
I adjust the headspace on my Savages for the particular lot of virgin/unfired brass I intend to use with that tube.

My personal rule on Savages. Shorter than Saami spec headspace is just fine. Never extend headspace.

 

[nhm16]

What your seeing is quite normal with factory chambers and off the shelf dies.
As the brass of the body is constricted it pushes the shoulders forward.

Yeah, I thought so, makes sense to me. The gun (secondhand) actually has a custom barrel, a Douglas from Sharp Shooter Supply. I guess Mr. Moreo chambers it for minimum headspace, which would further explain it (he explained in a thread in Savageshooters.com that if you screw the barrel tight against a headspace gauge, tightening down the barrel nut will further reduce the headspace another 0.001" or so).

As you surmised you need to get the die just a touch deeper to bump the shoulders.
Have you tried screwing the die in even further? Just touching the shellholder is'nt the end of adjustment with most presses. Theres plenty of mechanical slop to take up.

If screwing the die in further won't correct the problem a quick fix is stoning down the top of the shellholder. Most of my shellholders have been ground down.
I adjust the headspace on my Savages for the particular lot of virgin/unfired brass I intend to use with that tube.

My personal rule on Savages. Shorter than Saami spec headspace is just fine. Never extend headspace.

I will probably try grinding down a shellholder, then try re-headspacing the barrel using virgin brass. What do you use to grind down a shellholder?

I have a Lee Classic Cast press, and it doesn't seem to "cam over," like some other designs, unless there's something I don't see. If I screw in the die further the stroke of the handle just stops sooner...

Thanks for the advice...

 

[jo191145]

I use the Lee Classic too. If your adjusted down enough that the handle is not contacting the dead stop then you have indeed reached the end.
I've stoned my shellholders by hand on some large industrial stones I rescued from the trash. Same type of stones you'd sharpen a knife with.
Best method I've heard of is from a shooter on this site. Name slipped my memory or I'd give them a thumb up. Milinauk or NorCalMikie?? One of the two I'm fairly certain.
"Chuck the shellholder in a drill press and run it down on a stone" Wish I had thought of that myself :-[

Even by hand its not that bad a job.

It may be that Fred headspaced it for a crush fit on a certain lot of virgin brass by the owners request. Or the previous owner did it himself.
Thats how I set up my Savage tubes. Saves my brass from going through that big initial stretch on fireforming.
A good way to do it unless you can afford factory ammo. ;D

Screwing the tube in (shorten headspace) is good as long as you have clearence between the bolt head and barrel stub.
Screwing the barrel out(lengthen headspace) I avoid at all costs. That leaves more unsupported brass in the action. It may be just a few thousandths extra but I still avoid it.
I've been known to run my Sav actions very hard and they've never let me down. I try to give them no reason too ;D

 

[nhm16]

Thanks for you replies. I ground down one of my shellholders and was able to use it to bump the shoulders back 0.001".

I prefer to alter the die myself but if you go that route make sure you don't leave any burrs on the die or they will scratch your cases.

I came across people doing this to their Redding body dies. I am hesitant to do this myself as I don't have a lot of tools and don't want to ruin a $30 die.

 

[bglenn]

lynn
Lee presses have a stop on their travel they don't cam over.

Glenn

 

[Laurie]

W

hat your seeing is quite normal with factory chambers and off the shelf dies.
As the brass of the body is constricted it pushes the shoulders forward.

As you surmised you need to get the die just a touch deeper to bump the shoulders.

While agreeing completely with Mike and Joe as to what happens to the case during body sizing, I'd like to add that it is also very easy (if my experience with a Redding 6BR small-base body die is typical) to go the other way too and push the shoulder back excessively, especially if the rifle has been set up with a minimum headspace chamber.

Looking at the issues, it makes sense for the die manufacturer to dimension the die to do this given that heavy case-body diameter reduction will move the shoulder forward a fair amount. I would therefore expect these dies to produce excessive headspace (ie loose fit longitudinally) if adjusted to touch the shellholder in press operation. Mine certainly does!

The morale is to always check the case fit / headspace in any resizing process either using the riflle chamber itself as a gauge, or callipers and a headspace gauge like the Hornady / Stoney-Point models or the nice little brass collar that Harrell's Precision provides with its dies.

Laurie,
York, England

 

[gunaddicted]

PLEASE HELP SAME PROBLEM WITH MY Savage 10 fcp 308

Got some once fired wwsuper and FC brass fired once in my rifle measured the cases headspace with RCBS precision mic most were -2 or -3 from 0 the -3 could then be put through the neck die/lee collet and it would fit snuggly in my rifles chamber the cases that were -2 were too tight, so I put them through the RCBS FL die with the deccapper right to the top of die so that the button stem is flush with the roof of the die.(for runout) any ways, some of the cases come out with longer headspace usually when there isn't much lube then at times when there is a lot of lube the cases' headspace get smaller or the shoulder gets bumped much lower than needed as a result the case will bounce in the chamber.

I also find that putting the case twice through the die in the same motion will at first stretch the case then the second time move the shoulder back.

LUBE affects the shoulder of the case in FL die also the hardness of case. That is why I anneal after 2 firings before sizing.

I have also experimented with the Redding Comp Shellholders which are larger than reg shelholders in increments.

Compared to my friend that just puts his case through die and then sees if they fit the chamber, he does not measure and he seems happy. I am not a happy camper it is very tedious to measure each case before and after putting them through the FL die. I thought that by putting the lock ring on the FL die this would make the measurement for each case the same. Why does this not happen? Like I said,without moving the die (the die is a 1/2 turned in after touching shellholder) some cases will stretch but after putting more lube and passing it through the die a couple of times the headspace gets much shorter than I want it, sometimes it is perfect, most of the time I have to switch the shellholder, and all the time I have to measure headspace.

HAAAAAAAAAAAAAAAAAAAAAAAAAAAA IAM PULLING HAIR OUT HELP ???

 

[Laurie]

LUBE affects the shoulder of the case in FL die also the hardness of case. (gunaddicted)

The case hardness almost goes without saying. I'm not sure about annealing in that it may inject additional variables unless done with proper small workshop annealing gas-fired equipment. The traditional home-brewed methods of standing cases upright in water almost to the body/shoulder junction and heating the shoulder / neck areas with a propane torch before tipping the case over has been shown in many tests to give very inconsistent hardness levels. Personally, I prefer to use quality brass, keep batched cases together in MTM ammo boxes so each example is treated identically throughout its life and to switch use from match to practice after five firings. Minimising shoulder set back on each firing / sizing cycle must help too, and I've switched to Forster Bushing-Bump dies where available for the cartridge which are in effect neck-sizers, but resetting the shoulder position accurately. In .308W, I've found no need to use a body die in up to 10 loadings / firings despite minimum SAAMI spec chambers and 'warm' loads.

The lube issue is interesting and is rarely picked up on. I have a 'Precision Shooting' annual somewhere dating from the days when the magazine produced a compendium of selected articles from each year's issues in hardback book form. A very interesting study is included by a .308W High-Power Service Rifle shooter, this being back in the days when the M1A / M14 ruled this discipline pre .223 Mouse-Guns. Apparently, getting case shoulder position right (and consistent) is crucial in the M14. Too much headspace and accuracy suffers; too little and you get a breech explosion as the design allows it to fire with a partly locked action. The writer was appalled to find how much variation he was getting on resized cases and went into experimenting on this issue in a big way. His primary conclusion was that the type of case lube and the amount applied was the biggest single factor, compounded by variations in the way the press handle is operated.

I measure every 'match case' I load using the Hornady / Stoney-Point shoulder gauges after sizing and find a combination of Lapua brass, Forster Co-Ax press, Forster Bushing-Bump, and Imperial Sizing wax gives very small variations, maximum a thou'. The Redding Type S FL sizer die is only marginally behind the Forster. Dies are set so that there is one thou' shoulder set-back from the measured fired case length. With slight variations in the result this sees a small percentage of loaded rounds produce a barely noticeable resistance to closing the bolt.

I'm mostly talking .308W here, but standard Forster dies (and those from some other makers particularly Hornady) do almost as well with other cartridges. Like many long-time handloaders, I've come to trust some die and tool manufacturers over time so buy their stuff first. In my case this happens to be Forster or Redding, primarily the first named, and I know I'm not alone amongst precision shooters in coming to this conclusion.

This may or may not be the best way to size cases, but it works for me.

Laurie,
York, England

 

[jo191145]

gunaddict

First, if your mixing Win and Fed once fired from another gun and hoping to get the same results you won't. I'm playing with a 243 and Rem brass right now. With my FL die set correctly for Rem brass I can run in some Lapua 308. One might think it should be headspaced correctly. Its not even close. I have two hash marks on my die ring. One for headspacing Rem brass and one for forming Lapua.
Even if your Win or Fed is from two different lots you may get skewed results.
Best thing you can do is buy a lot of Virgin brass and stick with it.

What type of lube are you using? Sounds like your getting some very inconsistent amounts on your brass. As you've found this can mess with the measurements.
I use Imperial sizing wax. Have had great luck with it. I do not lube the neck or shoulders just the body. If my die is clean and dry I'll lube the first two necks or so then stop. Theres enough lube being pushed up from the body.
If using an expander ball with a FL die I use Imperial dry graphite inside the neck and wax outside.
Its an extra step but I do not need to clean out the necks afterwards.

FYI I've seen some reloaders that do not lube inside the necks while using an expander ball. I've even tried it myself on a few occassions. Usually this results in very hard extraction of the expander and can pull the shoulders forward.

 

[hogan]

A body die is a sizing dimension die which does not directly bump or touch shoulder or neck.

Nonetheless, any time a relatively soft and malleable metal like brass ctg cases is "sized" if that ctg case is of greater dimension than the die, the sizing action compresses and therefore causes the case material, brass, to change dimension. In this case it moves forward, or shifts.

If you have a minimum dimension chamber, not to be confused with a "tight-neck" chamber, then your brass will not typically "grow" in diameter. Brass expands upon pressure of firing, then springs back about .001" once pressure drops and bullet has exited barrel. So,,, If your chamber is about .0015 or .001 greater diameter than your properly sized case dimension, you won't see much if any ctg case growth when using a body die.

If your chamber is minimum dimension in terms of diameter and OAL, your brass if 30* shoulder or better will likely retain original dimension over many firings and give much longer case life.

The entire premise of the question is wrong though...
A body die will cause over-dimension brass to shift forward, thereby reducing the headspace the sized ctg has in the chamber it was fired in.

If you would alleviate the effects of the typical SAAMI spec chamber upon your brass, probably the best option is a custom sizer made to fit the fired brass for a particular rifle. LE Wilson will make custom dies

Too bad Forster isn't making a die-body resizing die like their Micrometer and benchrest seaters. Wouldn't it be great to be able to order a body insert for your sizer the way you can with bushing dies? For $20 in a range of .0015 under to .002 over SAAMI, there would be a pretty decent market.

After all, the only way to control what is really going on with your rifle, for the meticulous minded, is to specify each chamber dimenson to your toolmaker and own that reamer.

 

[jo191145]

All my body dies are quite capable of bumping back the shoulders.
A body die is nothing but a FL die that does not size the neck.
One uses their necksizer in a seperate operation to create the neck tension.
A body die that does not bump the shoulders would be of little use to anyone.

Brass fired in a sloppy chamber will flow forward in a body/FL die.
Obviously lowering the die more results in bumping back the shoulders.
That extra brass can now be seen in the neck as longer case length.
Upon firing that case length will receed as the brass flows backwards to once again fill the sloppy chamber.
The larger the chamber in comparison to the die the more this result can be seen.