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Total beginner here reading and getting setup to learn to reload, help me understand the effect of case sizing and its relationship to headspace.

The basic steps of reloading doesn't mention sizing the case to match headspace, can the sizing die be adjusted to fine tune the case datum length? Does the sizing die always push the shoulder back enough for all chambers? How will I know its too much?
 
By one of these to start...... It will tell you if the dies are set up to specs for any rifle. This is especially good if loading for semi auto so you can avoid a slam fire.


 
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Total beginner here reading and getting setup to learn to reload, help me understand the effect of case sizing and its relationship to headspace.

The basic steps of reloading doesn't mention sizing the case to match headspace, can the sizing die be adjusted to fine tune the case datum length? Does the sizing die always push the shoulder back enough for all chambers? How will I know its too much?

If all you're loading for is range ammo, pretty much any resizing die set up per the manufacturer's instructions will work, with a couple of rare exceptions. A case gauge like mentioned above is good insurance, especially when first starting out, if it fits the gauge, it will fit the vast majority of rifles chambered for that cartridge.

So with that said, here's a little deeper dive. Because ammo specs and chamber specs have a tolerance, and resizing dies are designed to work regardless of those tolerances, it's quite possible, even likely, that you'll end up overworking your brass. How much that matters will depend entirely on what you shoot and how much you shoot it. I have a couple of 5 gal. buckets of .223 brass, and I always pick up more at the range, so I don't really care if I get 5 reloads or 10 from my .223's. My Creedmoor, on the other hand, is my long range precision rifle, and I go to some pains to insure good brass life and consistent prep. This requires some additional tools, a case comparator so you can determine the optimal shoulder bump for that particular rifle's chamber and an overall length gauge to determine maximum bullet seating depth for each bullet you intend to use. Minimum shoulder bump generally means longer brass life, as well as improved accuracy. In a bolt action, .001-.002" is good, for an auto, it's more like .003-.005" to insure reliable functioning. The OAL gauge is nice to have if you want to experiment with bullet seating depth, although it's less useful if you have mag restrictions.

In some cases you can simply adjust the die to get the bump you're looking for, or you can resort to something like the Redding Competition Shell Holder set, I've done both, I like the shell holders better, but others say they're just a gimmick. Hope that helps, later.

Dave
 
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You can adjust head space gap with bottleneck cases by degree of sizing or use of neck sizing only dies.
With straightwall cases, I have never had one lengthen so they have never needed trimming. Cases that head space on a rim will not be effected by sizing. A case that head spaces on the case mouth can not have a zero head space gap as, in the real world, they start off too small and reduce in length with additional firing.
Let's say that you wanted to minimize head space gap for 9x19, you would take a 9x21 case and incrementally trim it until it just allows the gun to lock up. This would give best head space situation in your gun, but would not be safe for use in some other guns.
 
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Will the Hornady Lock-n-load headspace gauge work for this?
1614569608754.png
 
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Yup, that's what I was referring to above when I said case comparator. You start by measuring brass fired in your rifle, then set up your sizing die to bump the shoulder back by the amounts I listed above. Bear in mind, everything I said refers to full length resizing, if you're going to go with a neck sizing die, things are a little different. I've looked at both, as well as bushing dies, and have decided that for my loading, a standard full length sizing die is what works for me. Later.

Daved
 
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Yup, that's what I was referring to above when I said case comparator.
excellent cause I purchased that set today. I think I need to get Hornadys bullet comparator to go with. I originally bought neck size dies but after some reading and tips from another member here I bought some full length dies and will start with that. I need more reading on how to set up my full length die to set my headspace back a couple thou, then will figure out how far to seat the barrel back from the rifling.
 
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Just curious, what cartridge are you loading for, and for what type of shooting? Like I said before, if it's just range ammo for an AR, a lot of this is overkill. If it's a precision bolt gun, different story.

Good choice on the full length dies vs. neck dies IMO. I try to make ammo that's as close to the same every time as possible, with neck sizing, you're chasing a constantly moving target, and you still need to full length resize at some point. But that's just MY conclusions based on MY research, this is a deep rabbit hole, with plenty of room for lots of different ideas on the best way to do stuff ;). Good luck, and enjoy!

Dave
 

Mikej

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Will the Hornady Lock-n-load headspace gauge work for this?
View attachment 834947

When you get to using this ^ you'll be able to see the relationship between a brand new unfired round, a fired round and your resized brass. I use that unfired round as the basis for sizing my fired brass. Trim lengths, stated as "Trim To" in the book will put you within the specs for the chamber of the rifle. Something to note Re trim to lengths. One book states trim to length as 0.000". Another book will give two lengths, min and max. min= 0.000", max=0.010". This means you have 0.010" to play with when trimming. I don't want to trim more than I need to so I only trim for uniformity rather than trimming to the minimum.
 
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Just curious, what cartridge are you loading for, and for what type of shooting?
I should have put in the OP..., but Im reloading for my 25-06 for hunting. Im hoping I can cut my grouping in half from factory ammo and see if I can reach out another few hundred yards.
 
I should have put in the OP..., but Im reloading for my 25-06 for hunting. Im hoping I can cut my grouping in half from factory ammo and see if I can reach out another few hundred yards.
You'll cut your grouping by just weighing each charge to the exact same grains. Most hunting ammo has a variance and cheaper range stuff is even worse. This is one of the biggest advantages to reloading even my pistol plinking ammo is better than winchester white box, UMC, and remington. :s0159:
 

Spitpatch

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If your loading with those dies is dedicated to one gun (one chamber), and all else is identical you need no "comparator" gadget.

You can see precisely how much your FL sizing die is sizing on the neck of a sized piece of brass.

For accuracy considerations alone, you would adjust your die to size the neck just to the depth that your bullet is using in that neck. This leaves the rest of the brass, including the lower portion of the neck (relatively) untouched and remaining perfect for your chamber.

Yes, your neck will look like it has a barely detectable "shoulder" in it at the transition from fired neck diameter (your chamber dimension) to bullet retaining diameter from sizing. The portion of the neck that has been unsized is an additional aid to entire alignment of the bullet to the bore.

Yes, brass "neck sized" this way will chamber with slightly more difficulty than full-length sized brass or factory brass. Therefore, this technique is not recommended for a big-game hunt where slick and fast chambering is required.

Ideally, (for accuracy alone) you would buy a neck sizer for that caliber which would insure NONE of the rest of the body of that brass is sized. Again, chambering will still require a bit more effort.

Toward ease of chambering, the FL die can be adjusted to "bump" the shoulder just enough to one's preference for a slick entry to the chamber, and still preserve a significant portion of the fired case dimensions (as opposed to a factory new case that will rattle in with very little contact to chamber walls). This is a balance and a compromise that is regularly engaged.

All loaded cartridges should be cycled in the gun before an important big game hunt.

Chambering ease is less of an issue for targets/varmints, and in those applications one may lean more toward not sizing anything but the neck.
 
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Since this is for hunting I decided to full length size to avoid any tight chambering or stuck bolts. My understanding right now anyways is if done correctly full length sizing is as or more accurate than neck only sizing if you reload accurately to the chambers headspace, concentricity, and seat the bullet depth precisely to minimize jump but for hunting while still allowing for ease of chambering. Somebody correct me if Im wrong.
 

thorborg

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To each their own, for me;
I keep my head space house in order, but have never needed the extra OL and head space doodads when loading for hobby target, plinking and hunting. After thousands of handloaded rounds each reloaded many times sans these devices It is difficult to believe I've had a life time of luck. I believe they would be standing idle same as my case trimmer.
I do have other just as purportedly must have things like the case trimmer, that have been used a couple of times but now collect dust.
That said, Assuming you are talking about rimless shouldered cases, (since there are four different locations regulating cartridge head space,) a properly adjusted forming die whether FL or neck only, will place you in the headspace safe zone. All other chamber and bolt factors being shipshape. Worth noting the underlined "properly adjusted" because if not, will put a considerable wrench in the works.
This does not hold true for rimmed, belted or straight rimless semiauto stuff. If head space is out of whack, the latter usually being a case length/ trimming issue, while the former two, a bolt and or chamber issue needing @Velzey or his ilk.
But hey, if you can afford it and have the space, tools are cool, just ask my dwell meter and timing light that haven't seen the light of day in 30 years, but that's an obsolescent issue.:(
 

arrowshooter

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Since this is for hunting I decided to full length size to avoid any tight chambering or stuck bolts. My understanding right now anyways is if done correctly full length sizing is as or more accurate than neck only sizing if you reload accurately to the chambers headspace, concentricity, and seat the bullet depth precisely to minimize jump but for hunting while still allowing for ease of chambering. Somebody correct me if Im wrong.

In my book you are correct. I have never had very good luck with neck sizing only, ending up with tight chambering and tough extraction.

One thing that I do with a new rifle/barrel is I will strip the bolt when I can then size the brass until the bolt closes cleanly. I learned this while reloading for three different 8mm Mausers and now I have three different sizing and seating dies. My groups saw some major shrinkage when I started doing this.
 
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To each their own, for me;

But hey, if you can afford it and have the space, tools are cool, just ask my[UWSL] dwell meter and timing light[/UWSL] that haven't seen the light of day in 30 years, but that's an obsolescent issue.:(

I use mine alot but I have lots of friends with old cars...... even have to use the old non inductive one at times.
 

thorborg

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[UWSL][UWSL]My understanding right now anyways is if done correctly full length sizing is as or more accurate than neck only. [/UWSL][/UWSL]

I don't agree.
I believe, if used only in the same bolt gun, neck only sizing will usually produce better down range results. This from 25 or more years of neck sizing only, juxtaposed to same gun, same loads, but FL sizing the last 25 or so years. Admittedly though, the most obviously difference noticed, I get 3 or more less reloads per shell with FL dies than neck only dies otherwise it takes close scrutiny to find an honest difference. I cannot remember a bolt closing or extraction issue with neck only dies and the same gun except for a rechambered and caliber change jap rifle I had which I chalked up to being a poor chamber job.
Edit; this applies to bolt only not semiauto's
 

Spitpatch

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A serious misperception is expressed here,

: ...ending up with tight chambering and tough extraction."

and

"...or stuck bolts".

Huh? The fired case came out of your chamber. (I assume we are all on the same page here and speaking of ammunition fired in that gun previously.)

The fired case fits your chamber. The fired case came out of your chamber (the first, second or third time) just fine.

Now that you've neck sized only, firing it in the same chamber again will result in extraction being exactly what it was before. Because it fits your chamber just like it did before. Your brass cannot (given a proper load) "grow" any larger than your chamber. LIkewise you do not "gain" against the imaginary growth by "heading it off" through full length resizing. Even "oversized" (as done with "small base" dies) cases cannot prevent the case achieving the exact dimensions of the chamber upon firing.

"Tough extraction" and "stuck bolts" have NOTHING to do with neck sizing only.

Look elsewhere for that source of trouble and stay away from it.
 
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Having no experience (yet) with this I can only go by the majority of what I'm reading which has supported full length sizing over neck only both in benchrest shooters and for hunting applications...

I can only ask questions based on my understanding at this time, but my understanding is that neck sizing is an improvement over full length sizing when headspace isn't controlled, but doesn't control case runout which is an improvement over fireformed brass when headspace is controlled in the full length resizing.

Im open to all opinions but the good news is whatever I decide should yield an improvement over factory ammo so there might be an argument for simplicity, though my nature enjoys the technical details of things so I tend to favor whatever method will extract the most precision I can get for even just a hunting rifle.

 
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