Headspace issue

[esheato]

Hello all,

I have a bit of a problem.

I ordered a Redding Instant Indicator the other day for my 243 AI Cooper.

I set it up according to the directions. My goal was to measure the amount that my shoulder has moved so that I can set up a Redding body die to bump the shoulder back occasionally.

I zeroed the dial indicator on the set-up gauge and tossed a fireformed Lapua case in the press. Indicator shows -.010". Huh?

My cases are forming less than the minimum headspace? The only thing I can figure is that when they form from 243 Win to 243 AI, the shoulder/neck is pulling back to fill out the sharper angle of the AI case design.

Is my thought process correct?

Also, since I'm now below minimum, are there any issues I need to worry about? Does the case still fit as it should? I would think not, but I'm defaulting to you to for assistance.

I also have some cases that I've fired 4-6 times and they measure the same.... .010" below min.

Since they're not growing, I doubt I'll ever need to set the shoulder back. If SAAMI headspace tolerances are .010", that means I'm .010-.020" short depending on how my chamber is cut.

For the record, I'm trimming after every firing (easy to do with the Giraud).

Chamber length: 2.052"
Trim length (based off of shortest case in batch of 100 cases) 2.018"

Anyway, what are your thoughts?

Thanks in advance,

Ed

 

[atblis]

Possible depending on where it measures on the shoulder. The 243 AI is shorter towards the top (only by 0.004" in that diagram).
http://www.6mmbr.com/cartridgediagrams.html

 

[Walkalong]

I zeroed the dial indicator on the set-up gauge and tossed a fireformed Lapua case in the press. Indicator shows -.010". Huh?

Am I reading this right? The fired case is used to zero the gauge, then you size the case and the shoulder measures .010 less, as in pushed back .010?

If it is, you are sizing way too much. Please correct me if I am wrong. AC

 

[243winxb]

the shoulder/neck is pulling back to fill out the sharper angle of the AI case design.

Is my thought process correct?

Yes. On FL resizing with the body die, the shoulder and trim length should get longer. Put a shim between the body die & shell holder when setting up the die. Start with .010" thickness, will the bolt close on the sized case? If not, go to a .008" shim or smaller till the bolt closes. A feeler gauge works if no shim stock is available.

also have some cases that I've fired 4-6 times and they measure the same.... .010" below min.

If these cases were neck sized only, you have found your maximun chamber length/setting.

Since they're not growing, I doubt I'll ever need to set the shoulder back.

It takes a maximum pressure load to fully expand the brass. Spring back of the brass, after firing, will let you neck size only for a few firings, but soon or later, you will have to bump the shoulder back.

 

[atblis]

What are you using as your reference? You zeroed the gauge with what in it?

 

[fguffey]

My cases are forming less than the minimum headspace? The only thing I can figure is that when they form from 243 Win to 243 AI, the shoulder/neck is pulling back to fill out the sharper angle of the AI case design"

When I form fire cases, I FORM CASES, and I do it once, I do not use Wheaties, Cheerios, or grits, Others use cute methods and reduced loads, and wax, they use wax, they also use toilet paper, cut precisely.

I form first then fire, when I form first then fire after firing I get once fired cases.

What to expect when forming, measure before and after, do not be surprised to find the case shortens when fired. I have cases that shorten .035 thousands during forming, and shorten again during firing. Again, all rifle actions are not the same, then there is the part where time is a factor but not to reloaders.

Then there is the head space thing and SAMMY, I measure the distance from the bolt face to the shoulder of the chamber, I do not call that head space, I say the measurement from the bolt face to the shoulder of the chamber is the length of the chamber from the head bolt fact to the shoulder. After I have determined the length of the chamber from the bolt face to the shoulder of the chamber I form cases that fit the chamber from the head of the case to the shoulder of the case because my dies and presses have threads, and because my threads are 14 per inch I use a feeler gage, the companion tool to the press, the feeler gage.

The 243 is something like a 308 W, I form 308 W cases from 30/06 cases and that is how I can not miss when forming cases to fit my chambers, when starting with the 30/06 case, I erase the shoulder of the 30/06 then form the new shoulder to fit the chamber, and I do not know when 'BUMP' ended and forming started, I do not have a 'BUMP' die, all my dies, everyone of them are designed to form, when I form, the shoulder does not move, when I fire form, the shoulder does not move and that is the reason your cases shorten, if your shoulder moved the results would result in case head separation, Hatcher did not get case head separation, his shoulder did not move, had his shoulder moved on cases he fired he would have had case head separation, for his case shoulder to move the case would have had to stretch .080 thousands and his firing pin crushed the primer before the case, bullet and powder knew their little buddy, the primer, was hit, for Hatcher? time was a factor, for me? is a factor, others fire first then measure, I measure first then fire.

The Redding gage, nice, not necessary but nice, and expensive. 1858 did a review, according to his review it does not work, he measured 400 cases, his measurements were all over the place, Larry Willis helped him out with good solid advise, something like "over thinking the whole thing". I make home made tools out of nothing, I collect DATUMS, I make datums, I purchase datums for a little of nothing, I measure the length of the case from the shoulder to the head of the case, I use the length of the case from the head of the case to it's shoulder to off set the length of the chamber, I do that before I fire, I form first then fire.

I do not know what rifle you are using, I do not know how your chamber became an Ackley Improved version, there are at least three ACKLEY chambers, in the perfect world a factory, new, commercial minimum length/ full length loaded round has a short neck, shorter than the Ackley Improved chamber, when chambered the minimum length/full length sized case neck sizes when chambered and in theory, head spaces on that little part of the neck that will not fit the Ackley chamber, then when the trigger is pulled the rest of the case forms to the chamber, the rest of the shoulder is formed, the case body is formed and the case shortens, the neck is pulled back, part of the case body becomes part of the shoulder and part of the shoulder becomes part of the neck and the shoulder of the case did not move.

And I have no way of knowing what you are doing with forming cases from cases that have been fired 4 times, when forming/fire forming it does not get better than NEW CASES, anything after that is down hill and has failure built in to the method and or technique.

Had the opportunity acquire a few thousands LC National Match pull down cases for .08 cents each, I did not need the 30/06 cases, but when forming/fire forming nothing works as smooth as a new case and Pat's of Ohio needed the business.

F. Guffey

 

[fguffey]

And I read Reddings rational for spending big bucks for their tool for measuring what ever it is they measure, and like the instructions for chambering a rifle, there is nothing but the unknown and no way to determine information, like it is all thumbs without their newer than Larry Willis' NEW tool, when does a new tool become an old tool, and Redding has not discovered the companion tool to the press, the feeler gage, and I say there are other ways, other ways can be less expensive, acquired, more creative and innovative etc., and arrive at the same answer, but as 1858 said, 'NOT!!!' He also had a review of the Redding Competition shell holder, I have said a reloader, wildcatter, fire former does not need them, again, they are nice but anything that can be accomplished with the Redding competition shell holder can be accomplished with companion tool to the press THE FEELER GAGE.

I purchases a #6 set at the Mesquite Big Town Gun Show for $5.00 dollars, the deck height was marked on each one, of the 5, 3 were off by .001 thousands, my feeler gages are 'SPOT-ON'.

F. Guffey

 

[Ol` Joe]

There is no "SAAMI spec" for the 243 AI only for the 243 Winchester. The headspace should be the same but minute differences probably based on exactly where you measure might be found.
The 243 Headspace figures are
cartridge; 1.634" with a minus 0.007" tolerance
Chamber; 1.640" max and 1.630" min
These figures are taken from base of cartridge or breech to a point the neck measures 0.400" in diameter.
What ever the difference, the important thing is to match YOUR AMMO to YOUR CHAMBER. This is especially true with wildcats that can be built to minor differences in geometry depending on the maker of the reamers idea of how it should be.

 

[bigedp51]

esheato

I do not have a .243AI but I do have a .243, the GO gauge is "zero" reference used as a starting point. New .243 cases were anywhere from -.001 to -.009, fired cases were +.002.



I set/adjust the dies to touch the shell holder and then use the shims below gradually taking out shims until the resized cases are .001 to .002 smaller than actual chamber head space.



Some gadgets over complicate your life and make you want to pull your hair out.

Measure one of your resized cases for overall length and write this down, then insert a spent primer in the primer pocket with your fingers just seating the primer. Slowly chamber this test round and then eject, now remeasure the case and write this down. Subtract the first case measurement from the second and this will give you the distance from the base of the case to the bolt face (head gap clearance)

When you do the above you should NOT have a -.010 and you will be looking for -.001 to -.002 below actual chamber head space. In simple terms the primer should be protruding .001 to .002 and then you will know the die is set correctly to chamber your resized cases.

Sometimes fancy dial gauges are not needed, below a new Remington .303 British cartridge case in a Wilson case gauge.



Below a fired .303 case in the Wilson case gauge and it "IS" more than + .010

The British left room in the .303 chamber for the mud of Flanders.



I find the gauge below far more useful, it tells me if I have "any" stretching and thinning in the web area after fire forming the case.

 

[esheato]

The fired case is used to zero the gauge, then you size the case and the shoulder measures .010 less, as in pushed back .010?

No. I zero the indicator with the set up gauge.

For the record, I'm shooting Lapua brass. I have one batch (200 cases) fired 4-6 times. The second batch is 100 brand new that I've fired once. Both cases are measuring the same... -.010" short of minimum according to the set-up gauge.

Brass is formed by firing using a full power load.

My load process is:

1. Fireform w/ full power load.
2. Load 243 AI and shoot.
3. Neck size
4. Fire
5. Neck size
6. Fire

...etc. until the bolt is hard to close indicating I need to bump the shoulder.

Here are the directions for the Instant Indicator:





Page 2, I am following SET UP GAGE, DETERMINING YOUR HEADSPACE and SIZING YOUR CASES CORRECTLY.

If I'm reading the directions correctly, my steps should be:

1. Set up the tool and zero the indicator using the set-up gauge.
2. Measure fired cases.
3. Adjust body die to bump shoulder .002-.003" and verify using indicator.

Since the set-up gauge is the minimum chamber specifications, and I'm not sure where they got that info on an Ackley cartridge, I would expect a positive number once the cases are fired. Unfortunately, I'm getting a negative number.


Pic of set-up gauge next to fireformed 243 AI case.


Set-up Gauge in press.


Indicator zeroed on gauge.

The issue I'm having is that when I measure fired cases they show up at -.010". See pic below.



I called Redding today and they suggested that my chamber is cut short. They asked me to send in 5 fired cases and the body die for them to take a look at it.

I also called Cooper and asked what they thought...they had serious doubts that the chamber was cut short but said they were going to work with me to figure it out...unless you guys can figure it out.

Ed

 

[NCsmitty]

Actually you're showing about .0115" short in the pic.
Did you see the spec sheet on the reamer dimensions?



NCsmitty

 

[atblis]

See if the bolt will close on the setup gauge.

 

[243winxb]

I find it interesting that the instructions/chart does not list a "DL" for the IMP. When you get fired brass that is hard to chamber, zero your tool on the fired case. Then bump the shoulder back .002" or what ever.

 

[esheato]

Did you see the spec sheet on the reamer dimensions?

No. According to Cooper they use a standard Pacific reamer and it has a stop on it...so they ream to the stop and then back the reamer out. Reaming chambers and the knowledge that surrounds it is a bit out of my realm of expertise, so I'm taking their word for it.

See if the bolt will close on the setup gauge.

I'll be damned. No, it doesn't. I have no idea how I missed that.

 

[fguffey]

"I called Redding today and they suggested that my chamber is cut short. They asked me to send in 5 fired cases and the body die for them to take a look at it"

And again I check the length of the chamber from the bolt face to it's shoulder 'FIRST!" But to Redding, the feeler gage does not exist, all my dies and presses have threads, and when I chamber a rifle I always cut the chamber short, I also form short cases, if I like the way the rifle shoots, I finish the chamber.

If the chamber is short Redding Competition shell holders can not help, I suppose for big buck they could make a short decked shell holder. ME? I size cases in thousands from .012 thousands under a minimum length case to infinity, or a more practical .016 thousands longer than a full length sized/minimum length case, with the companion tool to the press, the feeler gage, that is 28 options.

F. Guffey

 

[fguffey]

Surprised the DL (Datum, reloaders call line) is not listed? I am not surprised reloaders and smiths are hung up on the DATUM as A LINE, I pull numbers out of the air, I make them up, I make them, I collect them and when the weight is in line with the money I purchase them, again I purchases 40 lbs. of dies, Wilson trim case holders, hammer out dies without threads, for $20.00, and that included a colet bullet puller with a .30 cal colet. And A Wilson 223 case gage. I make datums.

Transfers and standards, I make them also and I verify, again, the chamber does not get dark when the bolt closes, for me.

F. Guffey

 

[fguffey]

It is not necessary to grind the shell holder, it is not necessary to grind the die, Redding Competition shell h9older are nice, not necessary, anything gained by grinding the shell holder or die or the purchase of Competition shell holders can be accomplished with the companion tool to the press, the feeler gage, a decent feeler gage can be had for $11.00.

F. Guffey

 

[atblis]

You still need a known good reference. That gauge isn't guaranteed to be correct.

For a rifle that most likely will get fed nothing but handloads, a slightly tight chamber sounds good to me. Is that too tight...dunno.

If you're in no hurry and willing to pay a little shipping, I'd let Redding and Cooper figure it out for you.

EDIT: FWIW, my money's on Cooper having reamed the chamber a tad short.

 

[fguffey]

Or? make an effort to see through all the BLING, learn to measure the chamber before reloading for THAT chamber, get out of the habit of looking for someone trying to sell you something, to understand what is going on and going wrong is to understanding methods and techniques, the press and die have threads, that makes them adjustable, when I make an adjustment of my dies to the shell holder in my adjustable presses, I 'VERIFY' the adjustment with the companion tool to the press, the feeler gage.

I form 7.7 Japanese cases from 30/06 cases with a 308 W forming die, and the companion tool to the press, the feeler gage, and for those that have a clue, I just saved you $30.00+.

My favorite cases, those that are fired in trashy old chambers, the 280 Remington case and all cases that are too long to chamber, something like dumpster diving, not my choice, outside of CYLINDER BRASS manufactures do not sell brass to the few of us that know what they are doing, I want brass that is tooooooo long to chamber, tools required, A press, shell holder and a versatile full length sizer die and the companion tool to the press, the feeler gage, for short chambers when sizing a case, jack the case up by placing a feeler gage between the head of the case and deck of the shell holder (with a RCBS shell holder there is enough room between the deck of the shell holder and head of the case for a .010 feeler gage, Lee has more slack), if you are going to use cases fired 5+ times with primers, why bother.

It is worth it to me to use new cases when I want to move one measurement from one place to another, something like transferring one measurement to another place. And I do not have to reinvent the wheel ever day, I can sit down, form cases for a short chamber (example) 30/06, mark them and put them away for future use.

F. Guffey

 

[fguffey]

And the only reference I have is the chamber, when the bolt closes it gets dark in the chamber for most, I check head space from GO to BEYOND with a go-gage, I check go-gage length chambers with a field gage and when cutting a chamber I do not have to check often because I know where I am at all times.

The question was asked: How is one to check head space (or as I understanding it, the effect the chamber will have on the case when it is fired) with a 30/06 case that is too short for the chamber, and I said "Use a 280 Remington case".

F. Guffey

 

[esheato]

FWIW, my money's on Cooper having reamed the chamber a tad short.

Winner, winner, chicken dinner.

Since the bolt won't close on the gauge, the chamber is short according to Redding.

I'm going to send in the body die, the cases and shellholder. Redding said they will measure everything on a high end optical comparator and give me a true spec of the brass and I can take that info to Cooper and get the chamber fixed.

To say I'm a little disappointed is an understatement. I understand sometimes these things happen though...let's see how they fix it.

Ed

 

[fguffey]

"That gauge isn't guaranteed to be correct"

and without anyone around that has the ability to measure the gage or has the ability to use it as a standard or a transfer to verify the chamber, die, shell holder or press or to verify the integrity of the die, and then there is SAMMIES specs? + or -.

"FWIW, my money's on Cooper having reamed the chamber a tad short"

and I wonder what the decimal equivalent to a tad is. or a guesstimate of a turn is equal when there are 14 threads per inch. I know 1 turn is = to .071 thousands + very little, I skip the guesstimate and go straight to the verify phase, I make the adjustment with a feeler gage.

"Since the bolt won't close on the gauge, the chamber is short according to Redding"

Back to no promise as to the integrity of the gage. If I had a gage that would not allow the bolt to close (because the lights do not go out when the chamber gets dark) I can tell 'by this much' how much the bolt lacks closing, no tads, smidgens etc., in thousands. Again I make gages.

F. Guffey