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Old March 14, 2013, 09:14 AM   #1
RCP Fab
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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?

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Old March 14, 2013, 09:52 AM   #2
F. Guffey
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Today, 09:14 AM #1
RCP Fab
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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 backed off 1/4 turn, should it be brought lower than this?
The answerer is in the details, the die adjusted to the shell holder and or below is full length sizing, an attempt to restore the case to minimum length. You have the die backed off 1/4 turn.

If there was anything outside of making ‘wildguestimates’ in fractions of a turn or degree converted to thousandths the reloader would make adjustments off the shell holder in thousandths. Basically what you have is an adjustment of about .016”, I have one rifle with a chamber that has .016” added to the length of the chamber, when I size cases for that chamber I adjust the die off the shell holder .014”, I know, if Redding made a shell holder with a .014” deck height I could spend $40.00 ++ for a set of competition shell holders, instead I use the feeler gage to adjust the die off the shell holder, Redding shell holders offer 5 options between .000 and +.010. The feeler gage gives me 10 options between .000” and .010”. BIG PLUS, I can go to .020” and all the sizes between.

What it amounts to is you are beyond neck sizing with the full length aizer and not quite down to full length sizing, I do that, but I know the length of the chamber before starting. Again, I am the fan of cutting down on all that case travel.

F. Guffey

Last edited by F. Guffey; March 14, 2013 at 09:54 AM. Reason: add a . add a, and add an I
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Old March 14, 2013, 09:58 AM   #3
Bart B.
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I think the die's not low enough in the press.

Backing out a die 1/4 turn from shell holder contact moves it about .018". When a case is all the way up into that die so set, the die's bottom will be a few more thousandths away from the shell holder due to the press flexing or springing up from pressure. And the case neck won't go all the way up into the die's neck. That's what I think is happening.

Most full length sizing dies are best set when they're backed up about 1/16 turn or .004" to .005" above shell holder contact. One can use feeler gauges to measure this.

To be sure full length sizing dies are set best for long case life and best accuracy, they should set the fired case shoulder back no more than .002". The best way to tell is using a case headspace gauge such as the Hornady LNL or RCBS Precision Mic. These gauges measure the case head to shoulder distance.

Die threads are 14 per inch. One full turn moves the die about .072"

Here's a link to something that'll help you adjust die height in the press:

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

Last edited by Bart B.; March 14, 2013 at 10:08 AM.
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Old March 14, 2013, 10:17 AM   #4
RCP Fab
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I should have measured before I posted.

The lee instructions state to bottom the die then TIGHTEN 1/4-1/3 turn. Right now, with press flex it bottoms out fully.

Now to find a headspace gauge in stock...

Last edited by RCP Fab; March 14, 2013 at 10:22 AM.
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Old March 14, 2013, 10:20 AM   #5
AllenJ
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Quote:
should it be brought lower than this?
What you have done is a poor mans neck sizing job. The shoulder was not set back at all but where the case body meets shoulder it was re-sized slightly. I use this method from time to time when I don't have a neck sizing die.
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Old March 14, 2013, 04:14 PM   #6
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It depends on how the empty case (in the pic) fits inside your chamber, have you trimmed this case yet?
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Old March 14, 2013, 04:25 PM   #7
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What you have is the die is chambered too deep and base of die hits shell holder before shoulder of case is contacted. If you have a friend with a lathe have him whack about .015" off the bottom of the die and make sure to re-radius the die mouth like it is now.

The run die down leaving it about .012 off the shell holder and run case in, if you still get the line turn die about 1/8th turn at a time till you see that the shoulder is just touched.

I have about 60 sets of dies and I have had to trim about 15 of them to get them to size correctly.
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Old March 14, 2013, 04:31 PM   #8
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When sizing, look to see if the shell holder is in full contact with the bottom of the FL die at the top of the stroke. If not, screw the die in/down more. If sized brass chambers, your good to go. If they dont chamber, return die to Lee for adjustment.
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Old March 14, 2013, 05:04 PM   #9
RCP Fab
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I have a lathe at the shop.

The rounds chamber fine, some of these pieces of brass have been reloaded 3 or 4 times now. The brass is a little darker than usual after cleaning and it made the line visible.

That brass in the picture is not trimmed.
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Old March 14, 2013, 05:21 PM   #10
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You must have misread the instructions. Raise the ram with the shellholder in place and screw the die down until it toughes. The lower the ram and screw the die in another 1/4 turn to lower it. By backing off you are not allowing the dies to fully resize the case. 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.
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Old March 14, 2013, 05:33 PM   #11
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I misspoke in the first post, it was brought in an additional 1/4 turn.
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Old March 14, 2013, 08:29 PM   #12
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My theory on these type things is as follows: Does it chamber freely? Is it accurate? If yes and yes, dont worry about "fixing" it. I rarely ever make my press cam over. I usually tighten the full length dies until they firmly touch the shell holder. Rarely is a chamber so tight I need to cam over.
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Old March 14, 2013, 08:36 PM   #13
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With new cases, I check to see if they will chamber. If so, I put a nickel between die and shell holder and size. Fired cases are full sized the first time. After firing, a perfect fit to the chamber is obtained. Have done this for about 40 years with 8 different calibers.
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Old March 15, 2013, 08:40 AM   #14
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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"

Which means there will be almost that much head clearance for that round in the chamber. That's the same has having almost .016" excessive headspace for a normal round. Head separation will soon start and eventually crack the case wall at the pressure ring in front of the extractor groove.

Sorry, PA-Joe, doing this is a sure way to over size fired case shoulders. Too bad it's so often done by folks.
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Old March 15, 2013, 10:01 AM   #15
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Today, 08:40 AM #14
Bart B.
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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.

Again, I have one rifle that chambers cases that are .014” longer than minimum length, cases that are minimum length are longer than a go gage length chamber by .005”, the chamber in this one rifle is .011” longer than a go-gage length chamber/gage. Back to ‘I do not shoot gages’ I off set the length of the chamber with the length of the case. And that is the reason all my presses have threads, threads make my dies adjustable to and of off the shell holder, all that is required? I must know the length of the chamber from the shoulder of the chamber back to the bolt face.

Then there is the 1/8 turn of the die, .00898”, for those than can measure the length of a case after sizing from the shoulder back to the head of the case has 7 options between .000 and .008”, when making wild guestimates..., I suppose that is the reason a reloader would secure the lock ring to the die, once it is close they apply the leaver policy, once adjusted they leaver adjusted.

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Old March 15, 2013, 10:15 AM   #16
F. Guffey
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“I am getting a crisp line, about 1/16" above the top of the taper of case after resizing”

It is not that I would take the time to research the procedure but I am forming cases from 8mm Remington Mag, 300 Weatherby and 300 Win Mag cases with three different forming dies, the best dies for forming are the short ones, One step requires the die to be adjusted off the shell holder .340”, If I was really good I still could not make that adjustment with a wild guestimate. Once I get to the point success is greater than the chance of failure I box-up the dies ‘AND MY case LUBE’ then start forming cases to fit the chambers of a group of wild cat rifles.

Some of the cases were formed from 300 H&H cases, then comes annealing. Again, I make annealing tools.

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Old March 15, 2013, 12:58 PM   #17
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Here's a link to something that'll make adjusting dies very precicely:

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

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.

Last edited by Bart B.; March 15, 2013 at 02:04 PM.
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Old March 15, 2013, 03:27 PM   #18
RCP Fab
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I have the tools and knowledge to adjust the die. Right now the issue is the die is as far down as it can be. If it indeed needs to be lower, I will toss it in the lathe and shorten it up. I guess my question at this point is, should that line be touching the top of the taper on the case? I am assuming that it should be. I am also assuming that after I get to that point I need to measure my rifle, and adjust BEYOND that for proper headspacing. Can someone confirm that for me?

Thanks
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Old March 15, 2013, 04:10 PM   #19
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How can you guys have time to go shooting? F Guffey, Bart B.? you guys have so many numbers running through your noggins, how do you keep them straight?
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Old March 15, 2013, 04:43 PM   #20
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RCP Fab, you're thinking good. But making all those measurements for really good die setting to make really good ammo requires the use of a gauge to measure case headspace. Either the RCBS Precision Mic or Hornady LNL gauge will do well.

Then you can measure the before and after full length sizing case headspace then adjust you die to set the fired case shoulder back about .002".

Hooligan1, I only remember those two numbers that are important for setting dies. For all those those I forget, I can find them with grade school math using the ones I remember just like everyone else who forgets them but does remember the math. One of 'em's the threads per inch on the die. The other's "1" which the threads per inch is divided into to get thousandths per full turn of the die.
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Old March 15, 2013, 04:48 PM   #21
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Quote:
The rounds chamber fine
Then its a cosmetic thing? You want beautiful brass?
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Old March 15, 2013, 06:28 PM   #22
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You need to establish, for want of a better word, a datum line. I use a sinclair comparator tool. If you don't have one you stated that you have a lathe.
What you want is a bushing that goes over the neck and contacts the tapered part of the case halfway between the neck and the wall of the case. Using this bushing and a caliper you will be able to compare the datum line between a unfired case and a fired case. The difference in these 2 measurements will tell you if you have a head space problem occurring. they should be less than .005

If you measure the full length sized case and compare it to the fired case those dimensions will show you that you bumping the shoulder back to much. I would think if this is your problem you wouldn't have that ring at the bottom of the neck. Your not sizing your neck for its complete length. Look at your die and see if there is a ridge or shoulder in the top of the neck sizing area. if so you may have to trim the brass.
Regarding that situation I don't see anything wrong with that. As a matter of fact its a positive because when you chamber the round upthe unsized area will help center the bullet in the barrel. I do a lot of neck sizing and only resize my necks 3/4 of the way. I am using the unsized area to center the round in the barrel to increase the accuracy.
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Old March 15, 2013, 07:09 PM   #23
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Lucas, some comments on your remarks:
Quote:
You need to establish, for want of a better word, a datum line. I use a sinclair comparator tool. If you don't have one you stated that you have a lathe.
What you want is a bushing that goes over the neck and contacts the tapered part of the case halfway between the neck and the wall of the case. Using this bushing and a caliper you will be able to compare the datum line between a unfired case and a fired case. The difference in these 2 measurements will tell you if you have a head space problem occurring. they should be less than .005
Good idea. I've seen folks make one that's exactly an inch long with a .400" hole in it for .308 Win. cases. That's the diameter of the datum point on a .308 Win. case and chamber. With a 4" caliper, it's easy to measure case headspace then subtract 1" from the reading. You can look up your cartridge shoulder datum diameter in SAAMI's web site.

Quote:
If you measure the full length sized case and compare it to the fired case those dimensions will show you that you bumping the shoulder back to much. I would think if this is your problem you wouldn't have that ring at the bottom of the neck. Your not sizing your neck for its complete length. Look at your die and see if there is a ridge or shoulder in the top of the neck sizing area. if so you may have to trim the brass.
Also good info.

If one bumps fired bottleneck case necks back about .002", you'll get excellent accuracy and long case life. Sizing the neck all the way to the shoulder also makes it better centered on the case neck.

Quote:
Regarding that situation I don't see anything wrong with that. As a matter of fact its a positive because when you chamber the round upthe unsized area will help center the bullet in the barrel. I do a lot of neck sizing and only resize my necks 3/4 of the way. I am using the unsized area to center the round in the barrel to increase the accuracy.
I disagree with this part.

All bottleneck cases headspacing on their shoulders center perfectly up front in the chamber. Their shoulder angle's the same as the chamber. When the firing pin smacks the primer, that drives the case hard into the chamber shoulder perfectly centering it. Even a .243 Win. cartridge will center perfectly up front in a .308 Win. chamber. It doesn't matter how much clearance there is between the case neck and chamber neck; rarely, if ever, does the case neck touch the chamber neck when it's fired. The firing round's case neck has quite uniform dimensional space around it when its centered on the chamber shoulder. Chamber necks are larger in diameter than loaded round case necks.

If the bolt's got an in-line ejector in its head, the spring in it pushes the ejector forward also pushing the chambered round forward until the round's shoulder stop against and well centered in the chamber shoulder.

All of this is why benchresters switched over to full length sizing their fired cases a few years ago. Other top accuracy folks have been full length sizing their fired cases since the 1950's.
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Old March 15, 2013, 07:59 PM   #24
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B. Bart, your correct about the benchresters full length sizing. The benchrest people are utilizing very close tolerance (Minimum SAMMI) chambers that require neck turning inside and out. there necks don't expand .001 upon firing If the have and action with a spring button ejector they remove it or weaken it considerably. In a factory chamber the extractor button actually can push the cartridge to one side for possible misaligment in the chanber neck. note I said possible, not definite
Headspace gauges reference from the bolt face to the shoulder datum line not the neck. A 06 headspace gauge is used for all calibers from the 25-06 up to the 35 Whelen.
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Old March 15, 2013, 08:47 PM   #25
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Lucas, some folks full length sizing fired cases testing them in rifles for accuracy have been equalling benchrest tiny group records, sometimes beating them, with ammo fired in loose neck SAAMI spec chambers since the 1950's. Chamber necks do not have to be "tight" for best accuracy. Sierra Bullets has proved that for decades.

I've got a .308 Win. headspace GO gauge and there's no neck on it. It's .4000" diameter datum on its shoulder matches the gauging ring's diameter in my RCBS Precision Mic. I know how its shoulder centers in the chamber; exacly like a firing case does. Even made some contact tests and evidence shows 90% or more of the shoulder makes full contact with the chamber shoulder but it's very even all around the case shoulder even before the primer fires. That tells me the case shoulder is well centered in the chamber shoulder when it fires.

And all my rifle's extractors push the back end of the case at its pressure ring against the chamber wall; some to the side, others to the top. That doesn't hurt bullet alignment with the bore enough for me (and many others) to be concerned about. It's easy to calculate exactly how much it changes bullet runout. Best part of it is that it's amount and angle is repeatable from shot to shot so it has zero impact on accuracy.

Last edited by Bart B.; March 16, 2013 at 07:15 AM.
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