I bought new brass and when I check what the bump is based on a fired cartridge, it comes up -.013. I'm looking for a bump of -.002/-004. Since this brass is essentially .010 too short, is the only way to get my desired bump to load and shoot this brass?

Yes! Firing first is the only way,

I don't know of a practical way to stretch the base to shoulder (headspace) measurement of your brass without firing it and then sizing it correctly to your rifle chamber.

PS: most guys fire their ammo and then size their brass back to minimum specs which is the wrong way to do it, IMHO.

At least you're going to do it the correct way.

Zeke

PPSS:
I have heard of hydraulic case forming but I've never seen it used or know anyone who has, hence the wording "practical way"

Yeah that's what I thought. I hate having to waste powder, primers and bullets just to get brass I can properly siae. Also wastes my barrel life.

you need a solid shell holder.[no primer hole]

hydraulic forming is just compressing water in your case, inside a die.
it takes nothing more than a small hammer and a rod that fits the case neck.

oh,,, and a couple of towels and some water.

you can also form the cases through pressure.
not from a full load, but a high enough pressure load to swell the case up to fit the chamber.

stuff like red-dot, 700-x, bulls-eye and some cream of wheat are employed.

you save about 45grs. of powder and a bullet this way and you don't splash water all over the place.

No, firing forming is not the only way.

1. Expand the necks to the next caliber larger. (For example, if your cartridge is a 7mm use a .30 cal expander button).

2. Resize the expanded cases using your FL die with the die backed off of the shellholder the proper amount that it leaves a small "false shoulder" on the expanded neck that serves to headspace the cartridge on. (Instead of trying to use some over-priced device to measure this, just keep moving the sizing die down incrementally until the case chambers in the rifle with just a modicum of resistance. This is a more accurate way to perfectly headspace than trying to use some gadget.)

3. Now your "bump" is set the way you want it and your cases will not suffer any stretching near the head where the pressure ring develops.

If you fire them first, you are only stretching your brass at the inside web and shortening it's life; that is not the optimum way if you want max case life. That is the Worst way!
What Stone said, is best. Form a false/new shoulder and go from there.
Actually, best way is to set your barrel back to match your brass. That is my way.
What caliber do you have? Belted mags are made with huge shoulder gaps.
Another thing; maybe you have a rifle with excessive headspace instead of short brass.

The rifle is a Wby 30-378. I would not argue with you about the chamber. Yes, it's a belted case.

quote:

Originally posted by Stonecreek:
No, firing forming is not the only way.

1. Expand the necks to the next caliber larger. (For example, if your cartridge is a 7mm use a .30 cal expander button).

2. Resize the expanded cases using your FL die with the die backed off of the shellholder the proper amount that it leaves a small "false shoulder" on the expanded neck that serves to headspace the cartridge on. (Instead of trying to use some over-priced device to measure this, just keep moving the sizing die down incrementally until the case chambers in the rifle with just a modicum of resistance. This is a more accurate way to perfectly headspace than trying to use some gadget.)

3. Now your "bump" is set the way you want it and your cases will not suffer any stretching near the head where the pressure ring develops.

Be aware that sometimes when following the process outlined in 2 above that if using the same case and sizing incrementally you may get a false sense of the case being sized just enough to chamber with "just a modicum of resistance" as Stonecreek puts it.

When you run subsequent cases in your locked down die you may find they are hard to chamber. This is because you have set your die to the set point after sizing in small increments whereas sizing of subsequent cases is in one full increment where press and brass spring is greater.
This will probably not manifest itself with new cases just having the neck expanded then sized down but I can vouch for the fact that if using a fired case to size in increments to give a snug chamber fit, headspacing on the shoulder and not the belt, you will get the first one set nicely then subsequent cases resized can be too tight.

In this case you need to use a new fired case each time you incrementally screw the FL die down so your final setting for the die at lockdown will be on a fired unsized case.

Neck up then resize with a false shoulder then rock on with minimal stretch at the web and your brass life will also improve

Yes, what TT said; also as I said, belted mags have super generous shoulder to chamber tolerances; also, SAAMI allows far more tolerances on belted mags, than other cartridges; forget about setting your die with fired brass; that will only give a false reading.
So, so as SC or TT said and form a false shoulder and use that, on new bras. OR, use the "jam a bullet into the rifling" method of fire forming, and from there, NEVER move the shoulder back, too much. Assumnig the case body will still fit. Designers of belted mags did not have reloaders in mind.
But just firing rounds and sizing: no.

So, for 30 cal, what size should I expand the neck to? The example of 7mm to .30 is about .033 larger. If I used a 338 expander, it would be about .025 larger. no matter what, I'll need to get an expander button.

Has to be as large as the smallest part of the shoulder; so as to form a ledge for the case to rest against the chamber shoulder. So a 338 caliber expander should be ok.
Now, another method that one guy here uses; oil the case so it does not stick to the chamber; it will then set back and form correctly. I do not like to recommend this method because some idiot will get oil in the bore and bulge his barrel,....

Do both of what dpcd said! Form a false shoulder and jam a bullet into the rifleing! Now you will have GOOD BRASS!

Don't be cheap! This is supposed to be fun and educational!

Hip

P.S. ALWAYS headspace belted cases on the shoulder!

Thank you all. I have a bit to learn here.

Easiest way to expand a neck is to use a plug type die, like a Lee universal expanding die. Not a standard ball type expander; remember you are pushing up and expanding, not pulling there neck over the expander.

Great thread! I just keep learning . . .

Just like forming wildcats or AI ammo. Belted mags just have sloppy tolerances, except when I chamber them!

quote:

Originally posted by Barry B.:
I bought new brass and when I check what the bump is based on a fired cartridge, it comes up -.013. I'm looking for a bump of -.002/-004. Since this brass is essentially .010 too short, is the only way to get my desired bump to load and shoot this brass?

My cases do not have head space, and 'bump' is a function of the a press, there are 'cam over' and 'non cam over' presses; today reloaders claim they have been reloading for 55 years +- a few and I wonder what have they learned in all of those years.

Again, my cases do not have head space, I off set the length of the chamber with the length of the case "FROM THE DATUM ON THE SHOULDER OF THE CASE TO THE CASE HEAD".

He claims "this brass is essentially .010 too short" and I ask from where to where? I am the only reloader that understands it is impossible to "BUMP" the shoulder back.

Beyond a reloaders comprehension; I have chambered minimum length/full length sized 30/06 ammo in one of my M1917 rifles with a long chamber from the shoulder to the bolt face. The length of the chamber is .002" longer than a field gage length chamber. I could ask, "What does that mean?"

Back to 'bump'; when I chamber a round in that rifle and pull the trigger, nothing bumps because when I pull the trigger the case expands and when it expands the case locks to the chamber unless I lube the case and chamber. After the case locks to the chamber pressure builds the case stretches in length but by now you have forgotten the case is locked to the chamber meaning when it stretches' it can only stretch between the beginning of the case body to the case head.

Stretch & case head separation has been explained, and now we have the "BUMP generation.

F. Guffey

That is not true on so many levels; belted mags typically have very generous amounts of "space" between the shoulder and chamber. As well as generous SAAMI allowed tolerances between min brass and max chambers, relative to the belt.
Also, case stretch will result in brass separating; they do not just blow the shoulder forward.
Has nothing to do with the type of press. The OP may have confused some by using the term "bump".
The OP wants to make his new bras the same size as the chamber. Firing it, is they worst way to do that. In spite of what many think.
I explained how to make brass fit chambers above. Everyone is free to use their own techniques, albeit, less than optimal ones.

As far as NECKING UP is concerned I have some Hornady dies that I use to neck up with. These have an elliptical expander. I will expand up to and over a diameter that I want then neck down again.

Example---neck up 7mm mag. cases to .30 cal, then to .338 cal, them to .35 cal. then full length size (almost) back down to .338 to form .338 WM.

Final sizing to .338WM is a crush fit.

Different expander balls are available from Midway in different sizes for Hornady dies for about $8-9.00.

This method allows you to headspace on the shoulder of the belted case (which it should be)!

Hip

Correct. I have a need for necking up 30-06s to 40 cal, which I do in two stages; one to 375 and the second to 40. I use custom made expander plugs for that.
But Hip is right; Never trust belted mag brass to fit any chamber. This forum is replete with tales of stretched and separated cases by those who ignore this fact. Merely "sizing" them, won't work.
Here is what I use; I can make them for any neck expansion job, used in a Lee Universal expanding die.

quote:

Originally posted by F. Guffey:

My cases do not have head space,

F. Guffey

All cases have head space. You dont see it but it is there. When a chamber is cut it is cut within specific tolerances and set with go, no-go gages that only allow X amount of headspace. When brass gets a full length resize it is set to the minimum tolerance. The "bump" they are talking about is still resizing within tolerances, but it means simply getting the tolerances closer to the actual chamber dimensions for a given rifle. That is done by measuring a fire formed case and setting up your dies for minimal resizing, and no 2 chambers are exactly the same. and what you end up with is "custom" ammunition for a specific rifle that may not even feed in another like rifle. It is a precision rifle thing and for 99% of shooting it is not necessary at all. For me, happiness is a tight chamber.

Cases do not have "headspace"; only rifles do. There are tolerances in everything and I have said before, it is a miracle that anything is interoperable, given the relatively large tolerances in rifles, ammo, brass, and dies.
But this whole thread is about reducing that "space" between the brass and chamber, so as not to have it stretch, or break. And firing a cartridge is the absolute worst way to accomplish that. Remember, no rifle maker wants you to reload.

Without a case there is no such thing as headspace. If you want to get persnikitty about it, headspace is the measurable distance between the case head and the bolt face. So not only is a case a determining factor in said headspace, but as you pointed out, this thread is about minimizing headspace VIA the CASE!!

quote:

Without a case there is no such thing as headspace. If you want to get persnikitty about it, headspace is the measurable distance between the case head and the bolt face. So not only is a case a determining factor in said headspace, but as you pointed out, this thread is about minimizing headspace VIA the CASE!!

I use a term that is furnished by SAAMI; SAMMI uses the term 'clearance' as in the distance between the bolt face and case head. And then there is that part that drives reloaders to the curb; some place the clearance between the shoulder of the chamber and shoulder of the case.

F. Guffey



percipient/abrupt is what I did and my wife said persnikitty is a pie.

Oops; yes of course you are right!

I suppose both of "YOUS GUYS" (N.Y. lingo) are right!

The objective is LONG CASE LIFE and GOOD ACCURACY!

I try to set my shoulders back the minimum to get both of the above!

Example of current reloaded RANGE ammo

7mmRM---made from once fired range pick up brass---1st box(20) rds. 13 reloads!
2nd. box 14 reloads


.300WM--- once fired, 1st box---12 reloads
2nd box---18 reloads

.375 H&H AI made from NEW .340 Weatherby NOSLER brass

1st. Box---20 reloads
2nd. box---20 reloads

All of the above reloaded brass---ISN'T FINISHED YET!

I have some NORMA .30-06 brass that I have reloaded 30+ times---just lost the 1st. to a neck split.

Don;\'t push the shoulder back and anneal every 5 loadings!

ALSO, do the same with Rimmed brass!

Hip

As with many things, terminology gets stretched and twisted. MY understanding from reading that I have done is: headspace means the "space" between the "head" of your case and the breech. ALSO, headspace is from the breech to the chamber feature that limits cartridge insertion depth. Further, reloaders should minimize the headspace to prevent the firing pin from pushing the cartridge forward. From an article by Larry Willis " For handloading purposes, the term headspace means any chamber clearance that allows your cartridge to move or expand forward or rearward. There's no need to make things more complicated than that." So, in my case it is a belted case and the belt would control the movement of the case by the firing pin and the belt would be what sets my headspace. Now, another area of concern would be the space between the chamber and the case shoulder (which would typically be the limiting factor of cartridge insertion on typical non-belted cartridges). My understnding is that when fired, that "space" will become 0.000 OR, will at least be less than what it was before firing. So, I measure that space to be .013" with new brass. If I load and fire that brass, that "space" will get smaller even to possibly 0.000". (Yes, the case will expand and lengthen in other places but let's not worry about that for now. So, we will assume my new brass will upon firing push the shoulder forward until it contacts the chamber. So, it moves .013". Through sizing, I can adjust that "space" to more like .003". Each time I shoot and reload, I am taking the brass from 0.003" to 0.000" to back to 0.003". That's a lot less "working" of the brass than going from 0.013 to 0.003. So, my original question was what could I do to minimize any loss of accuracy by using brass (1st time) that had a .013 space between the shoulder and chamber and also, what could I do to esentially expand the case to close that "space" without wasting powder, primers, etc and actually firing the round. I did get my answer and have a path to follow. Thank you all. If I said something incorrect, please let me know. If you have suggestions, I'm open to listening. Thank you Tom. (FYI: so much is lost in typing words and trying not to be long winded.)

quote:

I try to set my shoulders back the minimum to get both of the above!

quote:

Don;\'t push the shoulder back and anneal every 5 loadings!

https://calguns.net/calgunforu...thread.php?t=1775933 Look at the first picture in this thread if you want to see what a shoulder looks like that has been pushed back. I have made devices that look like a thermostat bellows from an air cooled Volkswagen, I have made some that looked like a round accordion. All of this is in the design of the die and case body support.

I have found it impossible to move a shoulder back with a reloading die and it is beyond the comprehension of a reloader to understand; the shoulder I start with is not the same shoulder I finished with. If it was the same shoulder I started with I could say I moved the shoulder back. When I size a case part of the case shoulder becomes part of the neck and part of the case body becomes part of the shoulder.

Old Bart B was bragging about how wonderful he was at reloading (from the claims department), he claimed he had 45 firings with max loads with out doing anything to the case like annealing etc. etc. And I asked him about the weight of the case when he started and the weight of the case when he finished.

I was at the Dallas Market Hall Gun show, there were 5 of us at 3 tables, it meant nothing to me but a proud new gun owner walked up to one a friend since 1952 and accused him of screwing up the head space on the rifle he built (for the proud owner). I was proud of my old friend because there was a time that gun owner would have had trouble walking out of the building. Anyhow, I said nothing until the new owner walked down the isle and then got to me. I asked him about a case he used to make his point. I asked to see the case, I stood the case up the best I could and then asked the owner of the rifle if that was the only case he had, I asked him if he was shooting it over and over and over etc. He denied the case was the only case he had. I told him the case had been fired at least 45 times, I told him the case was soo thin it could not be sized and I told him the case was so thin it would not stand up straight.

The builder of the rifle moved down the line to find out what was going on, my friend never looked at the case when the rifle was presented for headspace. My friend suggested he go to a third party with the understanding he not tell him who built the rifle or tell him what I said about the case. He was gone for about 30 minutes, he came back, he was upset. The third party person cut the case open with a knife and then measured the thickness of the case.

And he asked; is this the only case you have, are you shooting this one case over and over and over? And then he said the thickness of the case was OK for paper but too this is too thin is too thin to be useful as a cartridge case.

F. Guffey

quote:

As with many things, terminology gets stretched and twisted. MY understanding from reading that I have done is headspace means the "space" between the "head" of your case and the breech. ALSO, headspace is from the breech to the chamber feature that limits cartridge insertion depth. Further, reloaders should minimize the headspace to prevent the firing pin from pushing the cartridge forward

Headspace. I measure the length of my chambers from the bolt face to the shoulder of the chamber. And then there is the datum on the shoulder. The most common datum diameter is .375" for the 30/06 family of cartridges. The 308 Winchester family of cartridges has a datum diameter of .400". And then comes a few Magnums, some magnums have a datum of .420".

Driving the cartridge forward with the firing pin. My cartridge has a primer, case, bullet and powder, all of my components add weight to the cartridge. When the firing pin hits the primer, the cartridge is sitting still and now you are going to tell me the primer does not get busted until the primer pushed all of that weight to the front of the chamber? I could give you an example but like everyone else you would not understand. I built an 8mm06, I chambered an 8mm57 into the 8mm06 chamber, I aimed and then pulled the trigger. I removed an 8mm57 case with a very short neck. Anyhow I was told it would not work so I did some unorthodox measuring and then decided it would work.

Headspace is not between the head of the case and the breach. If you have space between the bolt face and case head, you have clearance. Let us try this; you can use clearance, or you can use bump.

I have ejected fired cases that did not have a shoulder and I knew when I ejected them, they would come out of the chamber without a shoulder. what did I do? I must have cut down on all of that case trave.?

F. Guffey

quote:

I did get my answer and have a path to follow.

quote:

I measure that space to be .013" with new brass.

If I measured that space with a new case and found the distance was .013" I would say you have a chamber that is field reject length.

I have a rifle that has .015" clearance, it is a M1917 30/06 rifle, I am proud of the rifle, stamped into the wood stock are the initials EOK.

I am not a bumper, so this stuff does not drive me to the curb.

F. Guffey

quote:

Originally posted by Barry B.:
I bought new brass and when I check what the bump is based on a fired cartridge, it comes up -.013. I'm looking for a bump of -.002/-004. Since this brass is essentially .010 too short, is the only way to get my desired bump to load and shoot this brass?

May I ask what you are trying to achieve?

Belted magnums are notorious for being so inconsistent with their belts, and the sizing dies don't help much either.

quote:

Since this brass is essentially .010 too short, is the only way to get my desired bump to load and shoot this brass?

Again, I have a M1917 30/06 rifle with a chamber that is the length of a 30/06 with .015" clearance. I use 280 Remington cases. The 280 Remington case is .051" longer from the case body/shoulder juncture to the case head than the 30/06 from the case body/shoulder juncture to the case head. I started reloading before bumping was invented, I use a feeler gage, I adjust the 30/06 die off of the shell holder .014", and like magic I have a case that is field reject length.

The 280 Remington case is .041" longer than the 30/06 case from the end of the neck to the case head. The 30/06 chamber in the M1917 was go-gage length. The case was full length sized/minimum length with .004' to .005" clearance, I can't miss.

F. Guffey

I understand, you have a belted chamber, there was a time when I went to gun shows and firing ranges, I purchased many belted cases as long as they were it sets of 20. I found advantages to short, belted cases and long belted cases.

Saeed, Sorry, I've been away. My goal is the set the clearance between the shoulder and chamber to give or take .004". Now, why? First, it was my assumption that a tighter "space" would promote better accuracy. Next, it was my understanding that minimizing the amount you have to "work" the brass (for this topic at the shouder) would maximize brass life (again, only speaking of the shoulder). I realize my headspace is set by the cases belt which was why I called it "bump" and not headspace but I have been corrected on that "space" not being bump. So, to answer you, brass life and accuracy. With that said, I now understand that starting with brass having the shoulder to chamber space being ~.015" vs +/- .004" will have a minimal effect on the accuracy. I am going to shoot the brass as it is and when I reload it, I will set the shoulder to chamber clearance to .004" UNLESS, after fire forming the brass does not expand such that the shoulder contacts the chamber in which case I will keep it at the number it does conform to (meaning, if the clearance is .018" to start but after firing ends up let's just say .006" clearance, then I will keep it at that number). I may not be typing this exactly right but I think I have the process right in my head.

quote:

Originally posted by Barry B.:
So, for 30 cal, what size should I expand the neck to? The example of 7mm to .30 is about .033 larger. If I used a 338 expander, it would be about .025 larger. no matter what, I'll need to get an expander button.

When I re-chambered my .30-06 to .30 Gibbs back in the late '70s I had to form my cases with a false shoulder as has been described above.

I started with a Lyman M2 die and made long taper expanding plugs. I made the plugs from various diameter bolts and cut them on my "poor man's lathe," an electric drill, a metal file and a thread cutting die.

To expand the false shoulder for my .30 Gibbs I made a 0.33" diameter plug, the 4th from the left in the pic below.

A little Imperial Sizing Wax in the mouth of the case lets it slide easily over the expanding plug. I've successfully expanded cases as much as 7 mm RUM up to .375 RUM with one stroke and no splits.

Hydralic case forming: class 101

I purchased one from old man Gibbs for his Gibbs rifles back in the day,filled die with 30wt used a hand sledge to hammer the stem and it squirte oil all over my shirt, tried again using a bigger hammer and tighten everything up double snug and wacked it again, oil in hair, face, pants fly and cuffs, and worst of all on boots..

Sold my gibbs rifle it was mostly BS and over max max max to gain velocity..sold dies and case former with the gun..

All wildcats need to be fire formed, end of story!!

Easy Ray!

Your fingers must be smokin' after all the typing you have done today!

Hip