Full length resizing die question. Picture.

[PA-Joe]

Are you using the same brand of dies and shellholders? Each manufacturer uses a slightly different bench height on their shellholder. An easy solution would be to sand a little off the top of the shellholder.

[ScottRiqui]

Yes, Mr. Guffey, there is a conversion for fractional adjustments converted to thousandths. Multiply the fraction of die rotation by 1/14 and the answer's exact. 1/4 x 1/14 = 0.0178571428571429". .018" for 1/4 turn of the die is close enough for reloaders' use. 1/7th of a turn moves the die 0.0102040816326531"; .010" for all practical reloading use.

Exactly. The only way that a "distance per fractional revolution" conversion isn't going to be accurate is if the thread pitch isn't consistent. And if the thread pitch isn't consistent, the die would bind up and wouldn't thread.

[mehavey]

I'm going to ask about the elephant in the room:

> Does the case as sized fit back into
> the chamber, and the bolt close ? "

If so, the sizing die has likely done all the sizing it can on a at/below-minimum headspace case, and the case shoulder is never touched.

[Bart B.]

PA Joe asks:

Are you using the same brand of dies and shellholders? Each manufacturer uses a slightly different bench height on their shellholder. An easy solution would be to sand a little off the top of the shellholder.

Good question.

I've found no more than a .0015" spread across 3 or 4 makes of standard shell holder heights. That's well within reasonable tolerances.

In a conversation with an RCBS rep some years ago, he said the industry standard for rimless bottleneck case full length sizing dies is about +/- .002".

All of which to me means the spread across case headspace on such cases when the die's set to touch the shell holder with the press ram at its peak will be between .005" and .006".

But like barrel chambers and new brass headspace, there's sometimes over or under size die sizing chambers and shell holder heights.

All of which, for those wanting close tolerances on what they do, a case headspace measuring gauge is essential. And something to accurately measure the change in die height in the press.

One guy I knew years ago, before such gauges were made, measured his full length sizing die setting in the press with a depth micrometer or caliper measuring the height of the die top to either the lock ring on the die or the steel bushing flat that the die screwed into. 'Twas easy and cheap to make a .0043" change if that's what was needed.

[243winxb]

My testing shows the shoulder is not needed in some rifles for the firing pin to set off the primer. Case head is held by the extractor. My testing also shows the shoulder may be set back as much as .006" from the firing pin strike ( if shoulder makes contact with the chamber).This requires a loose fitting extractor & maximum head to datum brass. The ejector keeps the brass in contact with the extractor. My testing shows the head to datum measurement may get shorter on firing. My testing also shows 1/2 sizing of the neck will produce smaller groups when using FL sizing bushing dies. The unsized* part of the neck fully expands to the chamber in 3 or more firings, even in a factory chamber. People that think they know it all, may not know a thing. This may include me.

[Bart B.]

243, 'tis interesting to me that you've got rifles that hold the case head against the bolt face and that's where they're fired from. All of the various makes and models I've measured the max clearance from bolt face to the back side of the extractor lip that bears on the rim have a greater dimension than what the difference is in head clearance of cases correctly dimensioned for a SAAMI spec chamber. This includes the thickness of the case rim. While it's certainly possible to happen, it's my opinion that such excessive head clearance is not a good thing to have. I don't know of anyone whom would want this to happen if best accuracy's their objective.

I too, have measured a few to several thousandths shoulder setback from case shoulders slamming into chamber shoulders. And if the load's not hot enough to push the back half of the case enough to have the case head stop against the bolt face, the primers will protrude several thousandths past the case head. Cases from such circumstances may well have short enough headspace that they might be held back enough by the extractor to have the primer fire without the shoulder against the chamber shoulder.

Depending on how one sets up and uses their dies, 1/2 sizing of the neck will sometimes produce smaller groups when using FL sizing bushing dies. This is commonly called "partial neck sizing" for bottleneck cases. Sierra Bullets toyed with this process decades ago only to learn it was a disaster accuracy wise. Bolts don't close exactly the same from shot to shot as case headspace is too long for the chamber. What I'd like to know is, what's the test group size max with this compared to completely sizing the case neck back far enough to bump the sholder back 1 or 2 thousandths? Are cases so sized have enough headspace to cause a bit of bolt binding when chambered as you size them?

[reynolds357]

Bart, I know that Mauser type extractors and WBY Mark V extractors will hold a cartridge well enough for the firing pin to ignite the primer. I have built wild cats off both that I crammed a bunch of paper on top of the powder instead of using a bullet to fire form. The only thing holding the case was the extractor. I am quite sure that if I was trying to shoot groups with my headspace being held by the extractor my groups would be sub broad side of barn.

[Bart B.]

Reynolds, none of my classic controlled feed Win. 70's with Mauser style extractors hold a case off the chamber shoulder when they fire.

First heard of this thing decades ago. Later I ran tests with cases at minimum SAAMI case headspace in chambers with maximum SAAMI chamber headspace for both rimless and belted bottleneck cases. All had enough clearance from bolt face to extractor lip for cases with minimum SAAMI spec rim thickness. Some were with external extractors (early Win. 70's, 98 Mauser, FN Mauser, M1903, Ruger 77) and some with internal ones (Rem 7XX, post '64 Win. 70, Paramount, and a couple others I now forget). None held case heads back far enough to fire primers and their headspacing shoulder not touch the chamber headspacing shoulder. My indicator to see if bottleneck cases headspacing on their shoulders did not have their shoulder hard into the chamber shoulder was marking dye on the case shoulder. They all had chamber shoulder imprints on their shoulders. Folks believing otherwise should blacken primed case shoulders, slide the darned things into the bolt face, chamber them then shoot them. If the blackened shoulder shows no marring from shoulder impact, then the extractor did hold the case back.

Only if the case headsapce dimension was way, way too short, would an extractor hold the case back and fire primers without headspacing points stopping case movement forward in the chamber.

I disagree with your accuracy prediction of such poor rifle design and manufacture on being sub barn broad side in size. They'd be closer to the 10 acres of pasture the east side of the barn.

[reynolds357]

How is a rimless beltless case fire forming? When you get time, take a Mauser and cut a case in half with a pipe cutter and see if a federal primer will fire. Will have to pick the case up out of the magazine. My bet is a Federal will fire and a Remington will not.

[Bart B.]

How much firing pin protrusion from the bolt face can I have doing this excellent test you proposed?

In my tests with a 98 Mauser action, I slid the case into the bolt face directly; didn't use a magazine fed one.

[reynolds357]

How ever much the the rifle has. My Sweede has a lot. I plan on trying it myself Monday when I get to my shop.

[Bart B.]

One other claim by some is the extractor holds the case head against the bolt face.

Against? Pulled back against? Where does the force come from to pull it back? I've seen a lot of extractor styles and none of them had any pull-back force; only sideways.

To say nothing of how hard it might be for a rim to slide behind an extractor being pulled back enough that the space between its contact surface and the bolt face was smaller than the rim thickness.

[reynolds357]

You try it tomorrow and Ill try it. You might be right. If you are, I am going to have to do some serious puzzling on how I got that brass fire formed. I have always assumed it was extractor. If not, I have a mystery to solve.

[F. Guffey]

March 16, 2013, 07:51 AM #27
ScottRiqui
Senior Member


Join Date: January 27, 2010
Location: Norfolk, VA
Posts: 2,635 Quote:
Yes, Mr. Guffey, there is a conversion for fractional adjustments converted to thousandths. Multiply the fraction of die rotation by 1/14 and the answer's exact. 1/4 x 1/14 = 0.0178571428571429". .018" for 1/4 turn of the die is close enough for reloaders' use. 1/7th of a turn moves the die 0.0102040816326531"; .010" for all practical reloading use.

Exactly. The only way that a "distance per fractional revolution" conversion isn't going to be accurate is if the thread pitch isn't consistent. And if the thread pitch isn't consistent, the die would bind up and wouldn't thread.






Bart B.
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March 15, 2013, 10:01 AM #15
F. Guffey
Senior Member


Join Date: July 18, 2008
Posts: 1,495 Today, 08:40 AM #14
Bart B.
Senior Member


Join Date: February 15, 2009
Posts: 1,828 Here's an unsafe thing to do:

Quote:
Another thing you can do is keep turning it in 1/4 turn until the cases fit into the chamber. This way you are not over sizing the shoulders. There is nothing wrong with your die.

1/4 turn of the die moves it about .018". If the bolt just closed with a bit of binding on a sized case with a given die setting then the die was screwed down .018" (1/4th turn), the bottleneck case shoulder's now set back very close to .018". With the die's 14 threads per inch, there's about .072" between them (1 divided by 14 = .072 rounded up to 3 places). 1/4 turn moves the die 1/4 of .072". That's .018"



The die does not have a degree wheel, there is no conversion for fractional adjustments converted to thousandths. When adjusting the die there are only wild guestimates of a turn, I know, it has always sounded impressive with the 14 turns per inch, 1 turn =.07185714” and .01796 etc.. Rather than make wild guestimates I verify with a feeler gage, instead of wasting my time making wild guestimates, I go straight to the feeler gage, I back the die off, select a leaf from the gage, lay it between the shell holder and bottom of the die, make the adjustment then secure the die. To verify I use a thicker leaf and then a thinner leaf.


“The die does not have a degree wheel, there is no conversion for fractional adjustments converted to thousandths” On the press and or on the die, there is no indicator, or a pointer or draw-to-line, again, there is no degree wheel, there is no fractional index on the press and or die, again, there are height gages, there are feeler gages, there are verifying tools, and that part where the poor helpless reloader can not count of the threads being 14 per inch, poor helpless reloader does not have a tool for verifying and of does not posses the skill to determine if the threads are 14 per inch.

F. Guffey

[F. Guffey]

March 14, 2013, 09:14 AM #1
RCP Fab
Member


Join Date: February 22, 2013
Posts: 32 Full length resizing die question. Picture.

--------------------------------------------------------------------------------

I am getting a crisp line, about 1/16" above the top of the taper of case after resizing. It it's just a mark, I can not feel it with my fingernail. The die was bottomed out to the ram, and tightened 1/4 turn, should it be brought lower than this?

Thanks


Again, RCP Fab, the picture you posted indicate you are neck sizing, later in the thread you insist the die is adjusted down to the shell holder and the ram will not go up further. Adjusting the die down after contact with the shell holder will not reduce the length of the case between the shoulder of the case and head of the case unless the case has resistance to being sized, screwing the down further will increase the presses ability to overcome the cases resistance to sizing.

Back to developing skills in trouble shooting, if the die does not make it down to the shell holder when sizing a case the gap between die and shell holder will indicate the presses' inability to size the case in thousandths. One more time, screwing the die down further after contact will increase the presses ability to overcome the cases ability to resist sizing, screwing the die down will not increase the dies ability in reduce the length of the case from the shoulder to the head of the case, the dies ability to restore a case to minimum length is set by the deck height of the shell holder to the shoulder inside of the die.

More tools, beyond reloading, the spring/flex/give/flexibility of the press can be measured, I have three presses that are guaranteed not to flex/give/spring, there is no one left to back the promise or make parts for for the old presses, still out there are the old advertisements demonstrating the strength of the presses when compared to other presses. Added to one press in a bar that was added to a ‘C’ open fronted press, the bar attached to the top of the ‘C’ and attached to the press frame at the bottom.

Additional sizing can be gained by raising the case off the deck of the shell holder, to accomplish this method/technique it would be necessary for most reloaders to purchase a thickness gage from Redding or a feeler gage from Harbor freight or any other tool distributor that sells feeler gages. I form cases for short chambers, rather than purchase a short chamber die for $100.00+ I use the most humble tool, the feeler gage.

F. Guffey

[Bart B.]

Mr. Guffey, isn't this:

http://thefiringline.com/forums/atta...2&d=1259689721

...the solution to your remarks below?

The die does not have a degree wheel, there is no conversion for fractional adjustments converted to thousandths. When adjusting the die there are only wild guestimates of a turn, I know, it has always sounded impressive with the 14 turns per inch....

On the press and or on the die, there is no indicator, or a pointer or draw-to-line, again, there is no degree wheel, there is no fractional index on the press and or die, again, there are height gages, there are feeler gages, there are verifying tools, and that part where the poor helpless reloader can not count of the threads being 14 per inch, poor helpless reloader does not have a tool for verifying and of does not posses the skill to determine if the threads are 14 per inch.

I and many people believe it is. And I think the vast majority of reloaders are smart enough to figure this out.

I put this info in post 3 in this thread.

[F. Guffey]

March 16, 2013, 08:16 AM #28
mehavey
Senior Member


Join Date: June 17, 2010
Posts: 1,873 I'm going to ask about the elephant in the room:

> Does the case as sized fit back into
> the chamber, and the bolt close ? "

If so, the sizing die has likely done all the sizing it can on a at/below-minimum headspace case, and the case shoulder is never touched.



Again, nothing to gain by adjusting the die down below the top of the shell holder outside of increasing the presses ability to overcome a cases ability to resist sizing, no matte the strength of the press, the press is nopt going to crush the die, once the die contacts the shell holder all the crush is gone. The die protects the case from the reloader, the die is a limiter, the dies ability to protect the case from the reloader can be defeated, it has been repeated time and time over from the beginning, as in “all you gotta do is grind the bottom of the die and or top of the shell holder...etc.,...etc..” Redding makes shell holder that allow for sizing cases for long chambers, the shell holders were designed for reloaders that knew what they were doing, I do not find it necessary to spend $40.00 dollars for s set of shell holder that raise the die off the deck of the shell holder because I accomplish the same results with the companion tool to the press, the feeler gage. It should be no secret how far it is necessary to adjust the die off the shell holder, it all goes back to a reloader knowing what they are doing.

Again, working with the 50 Cal BMG chamber, gages, cases and dies. I Installed the full length sizer die into an A2 RCBS press, I adjusted the die down to the shell holder to .000” (contact, no slack), I then sized a 50 Cal BMG case, before I lowered the ram I checked the gap between the top of the shell holder and bottom of the die, the gap was .016”, “Gerdy, that is a gap!” Again, I did not have my choice of case lube, the die wanted to keep the case when the neck sizer plug was pulled through the neck when the ram was lowered. To full length size the case back to minimum length the die was screwed down an additional 2+ turns, again, when the ram was lowered the die wanted to keep the case, what a work out.

The good news? The case head spaces on the rim, I insisted we head space on the shoulder JIC as in ‘just in case’ , but that was more than others could keep up with.

F. Guffey