Length gauge post from another board

JCSC said:

What are your thoughts? Do people at the highest precision levels monitor the shoulder datum to Ogive?

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Did your post come from members/people on a forum that claims their forum is full of the highest level of precision shooters? I do not believe 'a highest level of precision shooter' would be using a Hornady comparator.

Keeping up: A shooter at the highest precision levels suggest reloaders should 'do like' the bench resters do; he suggested reloaders full length size their cases. I am not a precision of the highest shooting level because I do not have a rifle that cost $1,500+. When I start sizing cases for a chamber I determine the length of the chamber from the datum/shoulder to the bolt face. I do not apologize for using cheap tools but they are better and more precision than the Hornady comparator.

After determining the length of the chamber from the shoulder to the bolt face I determine the distance from the beginning of the rifling to the bolt face, again I make no apologies for the heap tools.

I have no interest in seating the bullet into the lands because I am the fan of the running start, I want my bullets to have 'that jump start'.

I have no interest is stacking bullets, but I do take pleasure when I load ammo for a rifle I built, they do that when getting ready for deer season; two of them sent pictures, they claimed they got 3 of if the biggest deer. they said there were 4 of the largest deer take. out of the 4 they shot 3 of them.

F. Guffey

Ohhhh Guffey....

Do we have to go thru this again...can't you just reference the last half dozen or so threads.

Easiest way I know of for setting up a sized for a particular bolt action rifle is to remove the firing pin and lower the size die until the bolt drops half way on a sized case. The case is compressed as the bolt is fully closed. I get the longest brass life and best accuracy most often with this method. Not to mention you don’t need a single tool to measure with to setup a size die this way.

JCSC said:

If you push a should way back, say .02” and hold the BTO, would the bullet bury in the lands, or will the bolt hold the shell back? Would the bullet utilize the jump and be gone before the case expanded to fill the rest of the chamber?

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Will bolt hold a case head against the bolt face? Remington extractor/yes. Savage extractor/No.

If head clearance/ slop in the chamber is of .020" because the shoulder has been push back to far, the Savage will allow the bullet ogive to move forward, till the shoulder stops forward movement. . If bullet is already jammed into the rifling at time of firing, the bullet will be pushed deeper into the case, with light neck tension.
Remington will blow the shoulder forward on firing.

When the bullet moves on firing and shoulder blows forward (Rem) or pushes the case head against the bolt face(Savage) is affected by neck tension. Tension provides a bullet pull* from a low of 35 lbs to over 100.

If a primer does not fire on a 223 Rem in a Savage Axis, the head to datum changes by .006" The shoulder is pushed back by the firing pin strike. A 2nd strike sets the shoulder back even more. When the shoulder moves back, the bullet may also. Trim length is shorter on fired brass and gets longer with fl sizing. (Most times).

There are military tests that show some primers will move the bullet out of the case mouth when there is NO POWDER in the case. Many reloaders had primers fire and there was zero bullet movement in bottle neck cartridges. I have seen no bullet movement when primers have fired. 1 no powder. More than a few with powder. In fact, H450 powder started burning, then just quit.

When the bullet moves & the neck expands, is still a mystery to me. Search here- https://discover.dtic.mil/

Edit* added "bullet pull"*

243winxb said:

If head clearance/ slop in the chamber is of .020" because the shoulder has been push back to far

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How is it possible to shorten the case by shortening the distance from the shoulder to the case head? Again, my dies have the ability to sized the case to minimum length/full length size. If we are talking about a 30/06 case the minimum length of the case is .005" shorter from the shoulder to the case head than a go-gage length chamber.

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243winxb said:

When the bullet moves on firing and shoulder blows forward (Rem) or pushes the case head against the bolt face(Savage) is affected by neck tension. Tension runs from a low of 35 lbs to over 100.

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Neck tension; I am the fan of bullet hold, again; there is no conversion from tensions to pounds, bullet hold is measured in pounds.

F. Guffey

Walkalong said:

And I wish fguffey could make up his mind if he can move a shoulder or not, or measure to it and move it the amount he wants. If he isn't moving the shoulder, maybe he is moving the case head. Something is changing when he sizes brass.

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From the beginning I have said it is impossible to move the shoulder back with a die that has full case body support. You have insisted you can move the shoulder back; I could ask you to explain to me how you move the shoulder back, again I said it is impossible to move the shoulder back.

I have always said I can shorten the distance from the shoulder to the case head but I did not shorten the distance by moving the shoulder.

F. Guffey

fguffey said:

From the beginning I have said it is impossible to move the shoulder back with a die that has full case body support. You have insisted you can move the shoulder back; I could ask you to explain to me how you move the shoulder back, again I said it is impossible to move the shoulder back.

I have always said I can shorten the distance from the shoulder to the case head but I did not shorten the distance by moving the shoulder.

F. Guffey

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You must have said this a thousand times. But it is vieled and you never finish your thought.

What moved?

How exactly does bullet jump affect accuracy ?

I could never understand this.

How does a difference of a few thousandths change anything when the bullet is teaveling diwn a 22 inch barrel ?

Precise bullet muzzle exit timing.

Seating depth can vary the pressures of the charge and alter the time it takes the bullet to exit the barrel.

It can also effect how concentric the bullet starts down the bore.

fguffey said:

Neck tension; I am the fan of bullet hold, again; there is no conversion from tensions to pounds, bullet hold is measured in pounds.

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The military calls it bullet pull & uses pounds and so does Federal with some Nato type 5.56 ammo. See my edit.

PSI is not pounds, but a good reference to how bullet hold/neck tension differs.

https://www.handloadersbench.com/fo...s/780795-another-neck-tension-thread-223-5-56
https://www.thehighroad.org/index.php?media/7-62-crimp-delayed-ignition-free-space.2285/

7.62 Crimp- Delayed Ignition/Free Space.
https://apps.dtic.mil/docs/citations/ADA341390 To avoid Delayed Ignition, use a mag primer, seat bullet deeper into the case, use a bulky powder that better fill the case. Increase bullet pull with a crimp, as a last resort. Crimps may hurt accuracy. Doing your own testing is the only way to know.

It is silly enough to say that a shoulder can not be moved back that I have to expect one of two things is true: either guffey is trying to describe something no one else in the thread is discussing, or he’s trolling. FL sizing dies, even with “full case body support” absolutely can and do move the shoulder back. It’s ridiculous to say a shoulder cannot be moved back - ridiculous enough that I’m struggling to avoid harsher language to describe it. It’s bad advice to say that to a new reloader, as intentionally confusing them with nonsense is irresponsible.

The highest level precision shooters don’t have to establish a shoulder datum to leade datum distance, because they know their case shoulder is placed where it should be.

The Hornady modified case and OAL gauge spindle come with instructions. Read them. They discuss how to correct for the incorrect length of the Modified case, referencing fired cases. It’s not complicated. Measure a fired case. Measure the modified case. If the modified case is longer, then subtract the difference between the two cases from your BTO measurement taken with your desired bullet. If the modified case is shorter (as it typically is), then add the difference between the two cases to the measured BTO length.

The bolt close method @jmorris described above is appropriate to determine case headspace. However, many of us don’t want a crush fit for non-Benchrest applications. It’s correct to say the bolt handle should willingly fall “about halfway,” but “about halfway” isn’t well defined, and isn’t the same for all applications. I also reference the feel of the finishing closure too. For non-Benchrest shooting, aka, any shooting for which I don’t want a crush fit, I size my cases to offer a palpable drag to close the bolt on an empty case, but I don’t really want to have the case oversized so much as to require more than light finger pressure to close.

Equally, @Walkalong provided a video of the best bullet seating method, the bolt LIFT method. If using jmorris’s advice for determining headspace, then your rifle won’t behave quite the same as the rifle in the bolt lift video - the bolt won’t freely fall as his does, BUT you’ll still feel that “click” when pulling the bullet on the bolt lift, and will still feel the increased drag of the bullet on the lands when you’re at your “kiss length.” I’ve investigated and experimented with almost every head spacing and seating depth method out there, and there’s nothing better than bolt close for headspace and bolt lift for seating depth.

The hornady tools are as precise as the process in which they are used. It can be easy to screw up while using them, making repeatable measurements impossible, but it’s also not so difficult to do it properly and yield consistent results.

fguffey said:

How is it possible to shorten the case by shortening the distance from the shoulder to the case head?

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A fl die that sets the shoulder back, (head to datum measurement,) .005 or even .010" may still have the same trim length?? Or will not shorten by the full .010" ?? Could the neck get longer. I guess its possible?
When case forming a 30 caliber down to a shorter head to datum 224 in a die, the neck gets a lot longer & needs trimming.

243winxb said:

Trim length is shorter on fired brass and gets longer with fl sizing. (Most times).

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The best part about that tool is that it can clamp to the blade on your calipers, so you only have to hold one object vs two.

That said, I often grab one of the hex versions because it’s instant to change from a datum for a shoulder measurement to a datum off the ogive.

https://www.sinclairintl.com/reload...r-hex-style-bullet-comparators-prod83792.aspx

Using calipers it is another part to hold though but I have a twin beam height gauge and surface plate in the reloading room that keeps it simple.



I also agree that none of the above is always needed or even useful. If I am loading ammunition to work in any number of correctly chambered firearms, a case gauge is better unless I find the one that has the smallest chamber and work off of it. OAL is often dictated by magazine length vs where the bullet might touch the lands as well.

I have always said I can shorten the distance from the shoulder to the case head but I did not shorten the distance by moving the shoulder.

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Is that the same as shortening the OAL but not moving the bullet?

Maybe if an officer asks “ do you know how fast you were going?”, the most accurate answer would be “Oh, about 1025 miles per hour.” Astutely adding or subtracting the earths rotational speed at the latitude/longitude and direction you are driving...

PWC said:

Do we have to go thru this again...can't you just reference the last half dozen or so threads.

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Demi-human said:

What moved?

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fguffey said:

highest precision levels suggest reloaders

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PWC, I noticed there were no responses to the OPs question, normally there are 'first responders'; and then the answers could be complicated. there was nothing keeping you from jumping in with something that would have been helpful.

You have said this a thousand times

and then, what moves?

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Forgive, I meant to include the part about "with a die that has case body support", I have also included the part about the shoulder I finish with is not the same shoulder I start with. I have also included the part about; "where does my shoulder go?" I have answered that questions many times. When I size a case part of the case body becomes part of the shoulder and part of the neck becomes part of the shoulder. And that is the reason a case gets longer when sized but does not always get longer when fired.

When fired the distance from the shoulder to the case head can get longer when that happens the neck gets shorter. Again that is because part of the case neck becomes part of the shoulder and part of the shoulder becomes part of the case body.

I understand it is much easier to say 'move the shoulder back' and or bump because reloaders assume they are understood universally, I don't.

I have suggested reloaders scribe the case at the case body/shoulder juncture. I have had scribed lines become part of the case body .127" from my new shoulder/case body juncture. The shoulder I started with is not the same shoulder I finished with.

F. Guffey

fguffey said:

.
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I understand it is much easier to say 'move the shoulder back' and or bump because reloaders assume they are understood universally, I don't.
.
.

F. Guffey

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I agree with you 100% in your assumption that you aren't understood universally. Astute observation on your part.

PWC said:

Ohhhh Guffey....

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I have modified cases, I do not use them but I have them Just in Case.

PWC, Can you explain the disadvantage to using the modified case, the OP used the rational of using it on different rifles. I believe my method and or techniques Is the better of the two.

F. Guffey

fguffey said:

The shoulder I started with is not the same shoulder I finished with.

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For God’s sake man... who cares if the same molecule of brass is a part of the shoulder or not. Everyone in the world who has ever sized a case understands and agrees with the vernacular when it is said, “sizing to move the shoulder back.” Dumbest argument on the internet this week, and of absolutely no value to our new reloader and his question.

[QUOTE
PWC, Can you explain the disadvantage to using the modified case, the OP used the rational of using it on different rifles. I believe my method and or techniques Is the better of the two.

F. Guffey[/QUOTE]

Guffey- My comment simply implies that the discussion of shoulder setback thru and inclufing headspace has been discussed in depth, greater than 20 thousand leagues, here in other threads. We may disagree to a minor extent on terminology (generational or regional) but otherwise your process is sound. But, restatement over and over and over.....

fguffey said:

From the beginning I have said it is impossible to move the shoulder back with a die that has full case body support.

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I don't usually disagree, but that's just silly.

Moving shoulders back, with a FL die, does exactly that. The walls thicken a bit, but mostly the brass stands still as the shoulder profile moves down over it, thus the idea of brass flowing into the neck during resizing. When you're done, the shoulder has moved, which is why we call it 'moving the shoulder'.

. . . and if you use an XDie, you can actually move the shoulder and mouth back together ~0.005. That's all case thickening.

fguffey said:

I noticed there were no responses to the OPs question, normally there are 'first responders'; and then the answers could be complicated.

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That is because you chose to complicate things immediately...


If everyone on the planet changes tires and you change your “inflated rubber pavement contacts points”, it isn’t everyone else who is wrong.

We get it.
The part that moves is the part where the head separates, (in addition to other parts that only move slightly...) but refusing to "let the beginner in on it" teaches them nothing about handloading or the movement of metals under stress. Acting arrogantly like no other human knows your secret moves neither the layman, the science, nor the sport further.

I say this only for narrative, as I’m sure you’ve heard this before...