Shoulder bump question.

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zbboy_zed

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Im Just on the edge of diving into reloading. So bare with me.
Out of curiosity, I've been measuring a bunch of my once fired factory ammo shoulder length and comparing it to the same brand factory ammo I've been shooting. And have noticed the shoulder on 98% of the cases only moved .001". Some move .002.
Does that seem to be normal or does it seem I have a tight chamber?

Should I still plan on bumping the shoulder back .002?
Or should I try for .001 if that's possible.

Ammo is hornady 300prc eldx.. IBI barrel.
 
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That's perfect.

That would be appx what your headspace measurement is as well, if your factory ammo cases are right on mean spec.

I used to fool around with measuring the shoulder lengths as well, using a bullet comparator nut type gauge I made up myself.

It's easy to make up. Just drill out a piece of metal, a large nut works well, so it slips over the neck on down onto the shoulder.

Don't worry about where it rests on the shoulder, because you're only measuring "stretch"

OP. If you want to get maximum life out of your brass, neck size only, if you're going to be using the cartridges in the same rifle.

This will make for a lot less flexing and stretching of the case, and extend its useful life. If you want to extend it much further, learn to anneal the case. Most folks only anneal the neck and shoulder. Not difficult at all.

If you're going to be using the cartridges in different rifles, you may want to bump back the shoulder with your full-length resizing die about .001 inches.

Load up one round without prime or powder, insert some plastic or epoxy into the primer pocket, and then insert a bullet to the overall length you will be loading your bullets. This will also work as a viable snap cap.

Use this dummy round to see if it will feed into the other rifles. If you're really lucky, your original rifle's chamber will be the shortest and you can just adjust your die to what it likes best.

An old bench rest trick is to neck size only. The tight fit of the cartridge in the chamber reduces inconsistencies found with factory loads.
 
I'm using the hornady headspace comparator.
And will only be using the hand loads In my own rifle.


What's the word on the street for hornady brass regarding how many times it can be fired?
 
Take a set of plain calipers and open them to .001”, then hold them up to the light.

You are worrying about an insanely small measurement!

Your variation is within the norms, quit worrying.
 
IME, it's not possible to hold headspace on a full length, bushing, and mandrelled cartridge to a variance of less than 1 thou. So aiming for 1 thou rather than 2 thou is a moot point, as you'll end up with a distribution of 1 thou, 2 thou, and 3 thou results.

I would recommend aiming for 2 thou as your most common outcome.
 
As above, sizing with a FL die, even set to partially resize, with result in a fair amount of variation from case to case. Nothing more frustrating than having 20% of your loaded rounds not being able to chamber. Ask me how I know..
Even at 2 thou, I would check the sized case in the chamber before loading. The alternative is to use a neck sizing die, which has other advantages.
 
Redding competition shell holders make life alot easier, they come in 2 thou bumps from 2-10.
Or neck size for a bit until they need a bump.
 
zbboy_zed said:
Im Just on the edge of diving into reloading. So bare with me.
Click to expand...

This is just my take, but to me it is foolish for a beginner to be worrying about advanced details.

I have never taken the measurements you are describing, in the 35 years I've been loading bottleneck rifle cartridges. I have never even considered buying the tools you are using. How about you just make some ammo that functions reliably and shoots okay before agonizing over this stuff that doesn't really matter to most people?
 
BattleRife said:
This is just my take, but to me it is foolish for a beginner to be worrying about advanced details.

I have never taken the measurements you are describing, in the 35 years I've been loading bottleneck rifle cartridges. I have never even considered buying the tools you are using. How about you just make some ammo that functions reliably and shoots okay before agonizing over this stuff that doesn't really matter to most people?
Click to expand...

Well this is an interesting reply!!

Its good that this new comer is trying to figure things out, and go the proper route.

I started reloading 2 years ago, and yes bought the headspace gauge, and other measuring tools. I pride myself into knowing that I can reload at a reasonable price so I can shoot 3 times more, and still have awesome accuracy. Now with a newly aquired chronograph I can also track how accurate my reloads are, with speed, and SD and ES numbers. Yea, I get it, not necessary, but it is a fun thing to have and now track numbers for my own sake.

To the OP> Yea, depending on your measuring device "tool" they may only at best get .0005" accuracy, and most are worse, so take that into consideration. You will also notice after a few firings you will get more "bounce back" in the brass, unless you anneal.
 
To find your headspace dimension.
-- you need a head space gauge

Factory ammo is loaded lower in speed and pressure than most reloads (while still being SAAMI pressure safe) so your expansion
is accurate for factory ammo but may not have reached desirable headspace dimension.

I found this video that answers the question you are attempting solve and does it well . Keith is a High Master F class shooters

Trevor
 
zbboy_zed said:
I'm using the hornady headspace comparator.
And will only be using the hand loads In my own rifle.


What's the word on the street for hornady brass regarding how many times it can be fired?
Click to expand...

Well, that depends on how you treat the brass and how you size the brass and your rifle's chamber and do you anneal. All those things will affect brass life.




BattleRife said:
This is just my take, but to me it is foolish for a beginner to be worrying about advanced details.

I have never taken the measurements you are describing, in the 35 years I've been loading bottleneck rifle cartridges. I have never even considered buying the tools you are using. How about you just make some ammo that functions reliably and shoots okay before agonizing over this stuff that doesn't really matter to most people?
Click to expand...

I kinda had this initial reaction as well.

Honestly, newbies should focus on making ammo that is safe and works. Do that for a few years before diving into the more detailed parts of reloading.
 
Trevor60 said:
To find your headspace dimension.
-- you need a head space gauge

Factory ammo is loaded lower in speed and pressure than most reloads (while still being SAAMI pressure safe) so your expansion
is accurate for factory ammo but may not have reached desirable headspace dimension.

I found this video that answers the question you are attempting solve and does it well . Keith is a High Master F class shooters

Trevor
Click to expand...

Is a "bug" to me - using a calliper to measure to four decimal places? And here I spent good money to buy a Mitutoyo micrometer to do that - stupid me!!! I imagine that calliper comes with a standard to set the readout?
 
Potashminer said:
Is a "bug" to me - using a calliper to measure to four decimal places? And here I spent good money to buy a Mitutoyo micrometer to do that - stupid me!!! I imagine that calliper comes with a standard to set the readout?
Click to expand...

Most people don't understand the limitations of the equipment nor of what they are measuring. It's the public educational system to blame. I once caught a lab worker measuring a loaf of bread to 4 decimal places. I rolled my eyes so hard I nearly fell over.

Not sure what you mean by a standard to "set the readout?" One simply closes the caliber jaws and hits the ZERO button. Calipers set.
 
I Dont Care About You said:
Most people don't understand the limitations of the equipment nor of what they are measuring. It's the public educational system to blame. I once caught a lab worker measuring a loaf of bread to 4 decimal places. I rolled my eyes so hard I nearly fell over.

Not sure what you mean by a standard to "set the readout?" One simply closes the caliber jaws and hits the ZERO button. Calipers set.
Click to expand...

A "standard" - used to be supplied with better micrometers - a ground block that was 1.0000" - used to set the read-out on the micrometer - as I recall, specific conditions of temperature, etc. that would influence the thing.

So, you had 0.0000", and then 1.0000" as "known-to-be-correct". As I understood, user was to assume that in between was correct - I only used a standard once, ever, on my 0-1" micrometer - I do not know if they are available in other dimensions.

Does not matter what the readout displays - on the box, the maker often says the tool is "accurate to within .001" - so what those words mean, I think - if the first three digits after the decimal say"2" "6" "7" with a calliper - that might mean the item is really 0.266", 0.267" or 0.268" - all those values are "within" .001 of that readout - what the maker said that tool was capable of - the fourth digit is simply fantasy.

Then take the same thing - like a bolt - set up and measure the diameter 5 times - I seldom get 3 identical numbers with a micrometer. So, what size is it, really?
 
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set the shoulder back 0.002". I've read opinions that 0.001 is within the elastic spring-back of the brass. AKA it bends and snaps back to the unsized dimension. Could be...

things to consider:
- resizing with the best die ever will still produce a spread in sized lengths. The better the die, the smaller the spread.
- annealing changes the spring-back so all brass has to be annealed the same.
- different lots of brass from the same manufacturer will likely spring back differently so don't mix lots.
- check the sized brass in the chamber. If the bolt is "hard-ish" to close on one or more case(s), size them all shorter.
 
If you really want to do a deep dive in all of this. Check out primal rights youtube. He goes in very deep detail in what why how much etc. Do you need to go that far? No. But it probably won't hurt to know.
 
From your link - the headspace dimension is 2.2000" +.0100" - the extra "0's" tell you to what accuracy they want the measurements taken to. 2.2" could be 2.24", rounded. You could probably measure 2.2" with a tape measure, but not going to measure to 2.2000" with one.
 
Potashminer said:
From your link - the headspace dimension is 2.2000" +.0100" - the extra "0's" tell you to what accuracy they want the measurements taken to. 2.2" could be 2.24", rounded. You could probably measure 2.2" with a tape measure, but not going to measure to 2.2000" with one.
Click to expand...

I'm pretty good with the tape measure... if I have my glasses on
:p
 
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