I have a RCBS Precision mic. Most of my brass is under the minimum ( short).
See pic this is 7mm rem mag
i have a RCBS neck resizer but can't bump the shoulder back .001
Am i diong somthing wrong or will this brass just not bump back.
If you enjoyed reading about "Can't bump the brass back .001" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
March 29, 2010, 06:41 PM
A neck size die does nothing to the shoulder.
If you need to move the shoulder back, (too long for the bolt to close) you need a FL sizing die.
If it's already too far back and you need to move it forward, firing it and letting it fire-form to the chamber is the only way to do it.
March 29, 2010, 07:22 PM
+1 on needing FL Sizing die. you can try all day but that neck sizer just isn't gonna do it. :D
March 29, 2010, 07:47 PM
Most of my brass is under the minimum ( short).
If your brass is already short why would you want to bump the shoulder back more?
RC is right... if indeed you need to move the shoulder back you will need a FL sizing die.
There is a way besides firing the too short brass, it involves using a .308 caliber expander ball (in a a FL 7mm Rem mag. die). then resizing again with the correct 7mm expander ball. This creates a false shoulder which will correctly head space(by the shoulder) the round. Depending on how many case you have already undersized would determine if this method would be worthwhile. It is safer than firing the brass, but it does cause extra working of the brass.
The 7mm Rem. is a belted round, it'll head space off the belt, firing it will work, but you face some case stretching if the shoulder is too short as you have implied.
March 29, 2010, 08:09 PM
the brass is short .001-.002 this shortness is realative to the head space gauge measurments. i have only use the neck resizer die for this brass.
March 29, 2010, 08:45 PM
When the round is fired, the brass expands to the chamber, then springs back .001" to .002" Some rounds on firing will get shorter, this is because the body expands outward in the oversize chamber. When you full length resize, your brass always gets longer, if you measure the trim length. The shoulder will move forward also on full length resizing, till it hits the shoulder end of the die. When only neck sizing, the brass may not expand fully to the chamber till after 3 firing or more if using a light load.
March 30, 2010, 10:54 AM
hci, you can only get an answer from a wildcat type reloader or from someone that forms cases, basic reloaders only have an ability to make fractional adjustments as in 1/1 turn of the die = 1 inch or 1.000, 1/8 of a turn of the die = .0071429, 1/4 turn of the die =.0142857 etc., and with no way to confirm/validate the fractional adjustment they are just making guesstimates.
And the only method they have to move a shoulder forward is to fire the case, a case that is formed first then fired is a fired case, not a fire formed case, or I could say I form cases first then fire. Back to the .001 thousands. I determine head space first, as with my Eddystone M1917 with .016 thousands head space, it is believed something bad will happen if a rifle is fired with .016 head space, over and over on the forums it is repeated that Hatcher reamed a 30/06 chamber by moving the shoulder forward .125 thousands and was amazed the case did not have incipient case head separation, today wildcatters and case formers call that firing an 8mm57 in an 8mm06 chamber by mistake, nothing falls off and all you will get is a very short neck 8mm06 case, the same when a 308W is fired in a 30/06 chamber, nothing falls off and you get a .400+/06 case (a 308 case without a neck or shoulder.
By determining head space first (length of chamber from the face of the bolt to the the shoulder of the chamber) I can adjust the die to the shell holder in thousands with the use of the companion to the press tool, the feeler gage. Instead of firing a case to move the shoulder forward, I find cases that are longer from the head of the case to its shoulder than cases used in my chamber as with the 280 Remington when compared to the 30/06, the 280 shoulder is forward of the 30/06 shoulder by .051 thousands, by being able to adjust the gap between the die and shell holder I can form cases that fit my Eddystone with .000 head space, I prefer .002 thousands, I have a unique press, when the die is adjusted down to the shell holder cases sized in it come out after sizing as FULL LENGTH SIZED or MINIMUM LENGTH CASES or the same as commercially sized cases, or cases that are .005 shorter from the head of the case ti it's shoulder than the SAMMY sized chamber by .005, if this is not obtainable, I want my money back. The allusive part is the SAMMY chamber, that is the reason I determine head space first because the SAMMY chamber is rare, the only SAMMY chamber I have are the ones I have are the ones I cut, and those are always short.
If you are sizing it means you have fired, what you do not want to do is move the shoulder back (much) if I had a SAMMY chamber and was sizing for it I would be happy with setting the shoulder back .001 thousands, this is not possible with a fraction turn of the die, a 1/64 of a turn is .0008929, then there is the part that is impassible to get over to a reloader, the fractional turn adjust men can be verified with the companion tool to the press, THE FEELER GAGE, imposable to understand why someone would guess the adjust men by fractional adjustment when they could go straight to the feeler gage, select a leaf and adjust the die. So for a .001 adjustment I would use the .004 thousands leaf and make the adjustment on a SAMMY chamber, again I do not take their word for it, I make gages to determine head space, I make tools to determine the effect the chamber had on a case when it was fired.
Cases that are too long because of being fired in non SAMMY chambers have a shoulder forward of the standard case, I purchase cases at the range for from .008 to .011 cents each, I do not need the cases, I need the cases that are too long from the head of the case to it's shoulder than the perfect minimum length case AND I know new cases are full length sized, again I want to know the length of the chamber in order to adjust the die to the shell holder.
March 30, 2010, 11:11 AM
Forgive, I did it, then I did not do it, I assumed spell check knew what I wanted.:rolleyes:
Excuse? I went to north east LA and removed, rebuilt and installed an engine in a 4WD Chevrolet P/U, I am having trouble raising my head and my arms will not go over my shoulders, it hurts to type (compose) and look up at the screen.;)
March 30, 2010, 11:45 AM
and I say bullet hold others say neck tension and I say bump sounds like an accident, there is nothing accidental about placing the shoulder where I want it, when sizing and dealing with the shoulder it is not pushed back, part of the shoulder becomes part of the neck, part of the case body becomes part of the shoulder, more like erasing and redrawing, again when I form 8mm57 from 30/06 cases the shoulder is formed .121 further back, I do not move it, I erase part of the shoulder, that part of the shoulder becomes part of the neck and part of the case body becomes part of the shoulder, deliberately? If I know the length of the 8mm57 chamber I know when to stop forming the case, nothing about that process implies bump, then there is the design of the sizer die, the case sizing portion of the sizer die is connected to the shoulder sizing of the die and it is connected to the neck portion of the die meaning sizing is relative, when the fractional adjustment is used or the 'washer' is used the case body can get sized if the chamber is non SAMMY as in being too large in diameter, this can cause the case body to be squeezed, this forces the shoulder forward (forms a small arch) and increase the length of the case from the case head to it's shoulder, but then being relative if the habit of sizing with guesstimates of a fractional adjustment was abandoned and the feeler gage was used with adjustment less than the value of head space the case body will be sized, the shoulder will be sized and the length of the case from the head of the case to it's shoulder will not exceed the chamber dimensions.
Then there are other type sizer dies that are not commercially made, but that is another story.
March 30, 2010, 03:47 PM
"the brass is short .001-.002 this shortness is realative to the head space gauge measurments."
If you are trying to match "headspace" to match the Mic's reading, forget it. Headspace doesn't matter to a reloader who knows what he's doin, he just makes his ammo match what it needs to be and goes on.
"i have only use the neck resizer die for this brass. "
Then you ain't ever gonna move the shoulders unless you change to an FL die.
March 30, 2010, 06:32 PM
If he was not confused enough already...he sure will be by now!
Could we say Information over load! What ya been taking for the head and shoulders!
... for someone who doesn't know that a neck die will not move a shoulder back... you may have sunk his boat!
Just Joking !!!!
Good Info though!!
March 30, 2010, 06:59 PM
I don't mean to imply that you are not smart or uneducated or anything remotely close.
What I was saying is that you may have skipped some of the understanding that you need to enter into the area of reloading you're trying to undertake.
May I suggest that you do some reading about how the various dies work and get a more through understanding of how they relate to the process of case sizing.
Most reloading manual have a section included referring to the dies and how they work.
Again I don't want to sound demeaning, but I feel that as the saying goes...You got your cart ahead of the horse.
March 31, 2010, 10:35 AM
hcl, .001 is complicated when using the standard thread of the die and press, 14 threads per inch (TPI), it is impossible to get the choir to understand the adjustment of the die can be verified by measuring the gap created when the die is adjusted, it is impossible to get the choir to go straight to the feeler gage to make adjustments, they insist on making fractional guesstimates in degree (without a degree wheel).
You have a precision micrometer, a micrometer that measures the effect the chamber had on a case when it was fired, or if you knew the head space of the chamber it could measure the effect head space will have on your case when fired. If I HAD YOUR GAGE and measured a fired case the information I read off the gage would tell me in thousands (.001) how wide the gap between the shell holder and bottom of the die should be to prevent oversizing my cases. I make my own gages out of nothing and I make up SAMMY specs. my chamber my cases, and DATUMS, I make up DATUMS, I purchase datums in boxes of junk and on occasions I have found them on sale at tool supplies stores, my biggest waste of time is spent making them.
Your precising mic is useful when the case length is measured first from the head of the case to it's shoulder, THEN, again after firing, the difference between the two readings will indicate the effect the chamber had on the case when it was fired. The question is 'What do you do with the measurement"? I transfer the measurement from the precision micrometer to the press with a feeler gage, always less, never the same and never more. The next response will be about 'spring back' I say recovery, they will say a bit (a term that does not have a value) I will will say "I do not care" the case has a memory of what it was or by design it shrinks, for what ever reason it aids in case extraction.
Side note, I have fired formed 30/06 case that resulted in the shoulder being formed so far forward the formed case had absolutely no memory of what it was before it was fired, it got what could be called a concussion, again extraction was not a problem.
One question, you fire a case, you measure the case with the RCBS precession Micrometer: What are you going to do with the difference between the case length before firing and then after?
Purchase books, read the instructions and research, no where in all of your effort will you be told how to transfer the measurement from the gage to the press, feeler gage, transfer and validate is not in their vocabulary, I make the measurement with out the precession gage because the tool to make these measurements does not have to be complicated.
If I thought you could not develop techniques and methods? That is not my decision. What you do with the information is up to you, all, part or none of it.
March 31, 2010, 10:54 AM
"Purchase books, read the instructions and research, no where in all of your effort will you be told how to transfer the measurement from the gage to the press, feeler gage, transfer and validate is not in their vocabulary, I make the measurement with out the precession gage because the tool to make these measurements does not have to be complicated."
Guff, it ain't all that complicated to require instructions. There are no adjustments to the press and none on the FL die except screwing it up and down; so, we screw with it until it's right! Learning how much to adjust a die actually comes pretty quickly if we have any one of a half dozen commercial gages to measure the shoulder change, feeler gages aren't really needed. ??
March 31, 2010, 11:05 AM
the brass is short .001-.002 this shortness is realative to the head space gauge measurments.
Your brass should be at about or around -.001"/-.002" of your headspace gauge measurements, to be in tolerance.
If it's above the HS guage specs,the ammo might not chamber or may chamber with difficulties.
March 31, 2010, 11:24 AM
hc1 has not been on this forum since "# Last Activity: March 29, 2010 06:09 PM" Its like talking to yourself lol Hopefully , he is reading the instructions. :D
March 31, 2010, 11:38 AM
Self is the only person that always agrees with what I say...so I talk to self a lot!
Jimmy K :D
April 1, 2010, 10:19 AM
hc1, I can only suspect you came to this forum to gain knowledge that would help you develop methods and technique. Looks like you have two options, one screw with it it until you get it correct? OR purchase a $11.00 feeler gage, if you purchase the feeler gage you can not only improve skill, methods and techniques, you can improve/increase your vocabulary with words like verify, transfer, and standard and take one measurement from the chamber to the press then back to the chamber.
Or you can screw with it until you get is correct, I do not use head space gages, I make gages that check head space in .001 (thousands), I do not purchase case gages (cost from $45.00 to $90.00) I make case comparator gages out of junk. I believe a measurement should go from the chamber to the press/die and back to the chamber, I believe screwing with it until one gets it correct is a short circuit between the chamber, press/die then back to the chamber.
You ask a question about something you believed was obtainable, an adjustment that would 'bump' the shoulder back .001, for short chambers I form (bump) shoulders back .017 without modifying the die and or shell holder and I make a tool to measure (verify) the measurement, 'out of junk'.
And when my answers sound like "das macht nichts - 'this/that doesn't matter' it is time for me to quit.
April 1, 2010, 09:46 PM
hc1, you already have all the measuring tools you need. But it'll take a full length sizing die to set the fired case shoulder back.
Mr. Guffey is trying to help, but he's confusing the issue and making it complicated. You don't need any feeler gages as your RCBS Mic is plenty darned good enough, and a lot easier to use. Guffey understands his tools and methods and they work for him, but he complicates instructions too much for folks at the lower end of the reloading learning curve.
First, clean some fired cases, measure one with your Mic to get its fired head-to-shoulder headspace. Write that number down.
Second, put the full length sizing die in the press then raise the ram all the way to the top. Screw down the full length sizing die until it's hard against the shell holder. Lower the ram.
Third, lube that case you just measured and put it in the shell holder. full length size it, then measure it's headspace with the Mic; the reading is the sized case headspace with the die so set.
Fourth, if the reading is not 2 thousandths less than what the fired case headspace is, adjust the die up or down by turning it about 1/10th inch on its circumference (about 5 degrees) for each thousandths of an inch you want to change its position up or down. Lock the die.
Fifth, repeat the third step, then the fourth one until the sized case headspace is 2 thousandths less than fired case headspace. Lock the die, clean, lube and full length size all your cases.
The most accurate belted magnums used in competition all do so with fired cases so sized. No neck sizing ever worked consistantly for best accuracy. It'll help accuracy and case life if you use a collet full length sizing die from www.larrywillis.com.
April 3, 2010, 11:53 AM
ISOMORPHIC, ISOTONIC, ISOMETRIC, ICONIC: Words that mean the same- something from the Greek word ISO, meaning the SAME, used in a sentence: Two Greek guys pass each other on the street, one says "Wasup" the other replies "ISO, ISO".
An example of 'ISO, ISO' is found in #4, there is the fractional turn of the die as in 1/4, 1/2, 1/8 without a fractional divided wheel, now we have the fractional adjustment in tense of an inch of the circumference, and the degree = thousands without a degree wheel, one (perfect) turn of the die = .071429, 5 degree divided into 360 degree (full circle) = 72, back to 1 turn (with an index) = .071429,
Now you have three choices, two are based on guesstimates if a fractional turn of the die without an index, not a problem, after making the guesstimates, check your work with a feeler gage, lower the ram place the feeler gage between the shell holder and bottom of the die, if the feeler gage is loose, choose another thicker feeler gage, if when the ram is raised and the feeler gage is tight, choose a thinner gage, or quit screwing with the die until it is correctly adjusted and go straight for the feeler gage, lower the ram, place the feeler gage on the top of the feeler gage, raise the ram THEN adjust the die down to the feeler gage until it is snug, THEN secure the die to the press with the with the lock/retaining nut, then check your work.
Skip the guesstimates of a turn, go straight for the feeler gage, it can not be more simple or less complicated. if you choose to make guesstimates check you work with the companion tool to the press, the feeler gage.
April 3, 2010, 02:43 PM
sorry about that,
place the feeler gage on top of the shell holder, raise the ram then if the tern is 'screw' not adjust, screw the down until it contacts the feele gage and finish by securing the die to the press with the lock nut.
If you enjoyed reading about "Can't bump the brass back .001" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!