Do I need FL sizing die?

[Trickymissfit]

FL sizing is a choice, but not a single choice.
The choices leading to FL sizing, or successful avoidance of it:
-Cartridge design
-Chamber body clearances
-Load pressure
-Amount of barrel steel around a chamber

CARTRIDGE DESIGN: large capacity cases with high body taper and low shoulder angles (like a 30-06) will have to be FL sized.
CHAMBER BODY CLEARANCES: On firing, cases hit and follow expanding chambers walls. Once pressure drops, the case and chamber walls spring back. With big clearances from 'new' case dimensions, firing will expand the brass to the point of yielding. These now larger cases are thinner by as much. Thinner cases spring back less, while the chamber springs back fully(it better), potentially leaving an interference fit.
High LOAD PRESSURE and insufficient BARREL STEEL AROUND CHAMBER go hand in hand at this point to do the same as excess clearances, even without excess clearances.
These conditions are chronic, and they are choices today.

Shoulder bumping is another subject, but similar in cause/effect and commonly needed. An added cause/choice directly contributing to this, is excess head spacing.

I don't and never will FL size, as this is among my choices.

if you use a neck only die (and I do a lot of the time) you will eventually have to set the shoulder back. There's no way out of it. You can buy a bump die and push the shoulder back three or four thousandths and start all over again. But if you have a full length die your already doing this (if you have it setup right). Now the part about neck sizing only really partains to a custom chamber as there is little benifit gained from neck sizing a factory chamber. Many of us still do this in factory chambers to reduce bullet runout by turning necks, but other than that there is very little to be gained. By chance that you were lucky enough to get a chamber cut on the minimum spec, then there is something to be gained of course.

Now if you happen to be shooting belted cases you will eventually get to the point where the area just above the belt will get tight. A standard full length die won't get you there most of the time (if any at all will). Then you need a die to also resize that part of the case. I see that with my .450 and my .270 mag after four or five high pressure loads. They'll still chamber, but they are a little tight.

I agree with you about the barrel/bridge expansion and the brass meeting it's yield strength and beyond. I know of no one that goes thru life entirely with a neck die, but also know lots and lots of folks that neck size a lot of the time.
gary

 

[Bullet bumper]

I'm in agreement with Bullet Bumper, and follow his route.

Once my cases are fully fireformed(via partial NS only with 3-4 firings), I measure & cull by H20 capacity. Within a couple firings it'll be time to bump ~30deg shoulders 1thou(higher angles = less often, if ever). My bump is with Redding body dies, or if chamber/die mismatch, I go to JLC Precision custom body dies. I partial NS using Wilson & nitrided bushings. Some of my Wilsons were blanks cut with my reamers.

I have never had to replace a piece of brass. With my loads, dies, chambers, & this sizing, it lasts forever. Given this, I don't lose any sleep keeping ~120 perfect cases per 1,000 measured, and further culling out ~20-30 from ~120 due to H20 capacity departures. I get 80 or so cases that match in capacity,, will always match, and they will not grow in loaded runout.
I also never need to re-trim(which is one reason my cases remain matching in capacity).

For those who think FL sizing is a shortcut; it's not always. Not in the long run.
Here I'm talkin about actual FL sizing(not body/bushing sizing) and not FL sizing with a custom die(which could be excellent). Just off the shelf FL dies, which lead to continual trimming.
These, I will never use.

And running extreme pressure loads?
Everything comes with a price, and I chose to stay away from this.
I know these loads work around other tough issues, and if I were a PB BR competitor, I'd go this route also.
But with larger cartridges the price returns more pain than gain.

Nice to see a switched on reloader well done.

 

[sceeder]

Stick with Redding or RCBS dies. I've had most all of them and those two dies never gave me any trouble, the others did.

 

[DocB]

Mikecr, thanks for sharing your techniques very much.

But after studying a bit deeper what you wrote I have a couple of questions if you don't mind...

1. When do you (if you do) anneal?

2. Do you load your final preferred load only after you have fire-formed your cases? In other words you don't work up loads on non-fire formed cases?

3. Regarding H2O capacity, do you develop a 'reference' capacity for your fire formed brass only? Seems to me that the H2O capacity would be greater on fire formed cases as compared to the same lot of unfired cases.

Am I on track or confusing myself and wandering off into minutia?

I truly appreciate all your time, patience and expertise sharing.

Doc

 

[g0rd0]

I dont know how mikecr develops h2o case capacity (cc). but here is how I do it.
fire 10 rnds, deprime and neck sise then clean the brass
trim to lenght and put your bullet on top and seat it by chambering in your rifle
weigh the 10 then divide by 10 to get the average weight of an empty rnd
now useing a hypodermic needle fill each one with water through the flash hole (use a q tip to wipe water out of the primer pocket)
again weigh and divide by 10 subtract the average low from the high and that is your case capacity
every time you change bullet stlye or weight the cc changes


another note, at the same time as you chamber your dummy rnds put a rod down the barrel measure the distance from the muzzle to the tip and add the lenght of the bullet this will give you your true barrel length and the cc and barrel lenght =expansion ratio (er)

 

[Mikecr]

1. When do you (if you do) anneal?

I lead dip anneal to the depth where brass will yield in fireforming. I do this during preps, and as needed with necks to keep neck tension consistent(not very often from my sizing).

2. Do you load your final preferred load only after you have fire-formed your cases? In other words you don't work up loads on non-fire formed cases?

Working up powder loads with new brass is a waste of time, even if you intend to use only new brass. I only test for optimum seating during fireforming.

3. Regarding H2O capacity, do you develop a 'reference' capacity for your fire formed brass only? Seems to me that the H2O capacity would be greater on fire formed cases as compared to the same lot of unfired cases.

You're correct that capacity increases with fireforming, even with FL sized brass.
I measure capacity only when the cases have stabilized in all dimensions, which is 3-4 firings with no body sizing. Trim lengths reconfirmed and touched up if needed.
With FL sizing, capacity will vary, and over time, with every bit springing back from it. No getting around this.

 

[sceeder]

I know nothing about fire forming. I do know that RCBS in Redding dies a great.

 

[DocB]

Mikecr, g0rd0

Thanks very much for you sharing and your advice. It's very much appreciated

Doc

 

[bigbads10]

Thanks guys that was a good read and learned lots. Good to see other guys out there helping others.

 

[BountyHunter]

Caution on the details of Mikecrs technique and its non applicability to the majority of LR hunting cartridges.

It works great IF you limit your reloads to 53,000 PSI as Mike has stated he does. Most LR cartridges have Max pressures of 60,000-65,000 and most are shot there. Plus the largest cartridge case he reloads for is a 6.5 WSSM(WSM). Both of these are not normal LR hunting cartridge parameters or even SR BR pressures.

So if you are loading to Max end pressures as most here are you can dang well bet FL (body and neck) will be required or throw the brass away after 4-5 reloads. Now custom matched FL dies are your best bet to minimize sizing as he stated.

 

[Mikecr]

But then loading to max pressures IS a choice. Right?
I suggest there is no particular reason to do so, or assume so, with hunting cartridges.

Lately I've reloaded for 6br, 6xc, 223, and 26wssm. I've managed well at ~55kpsi for these, except my best load for the 26wssm(IMP) is running 64Kpsi(SAAMI max for it).

The load for the 26wssm:
47.4grIMR4350 @ 3020fps. 139LAP - 1.985OgvOAL, BR2, 28" barrel.
This plays with any 260AI(same capacity), or 6.5x284, and would suffice for LR hunting.
I mention this because it is my highest pressure load, but nowhere near where I've had it in testing(+3200fps).
I'm on my second barrel with it, and some of the original ~80 cases I've prepped/culled must have 30 or 40 reloads on them by now. And given that they still exactly match my reference fireformed case, I'm certain they will last forever as they have.

Now if I went with a faster load/powder(H4350), higher pressures, I could reach a node that would flat out pass most 6.5x284s. It might also shoot as well faster I don't know. But with this, I would have to FL size, and my cases would no longer be matching, and my primer pockets would open before long.
Doesn't make sense to do this. Not with a milder 3020fps node at hand.

Nothing about my 26wssm turned out by accident. I drew up the chamber reamer with brass/bullets in-hand, to produce desired capacity and case angles. I drew up the sizing reamer based on what I knew the cases would go to(for custom dies). I had already worked out the best load potential with QL. I went with a magnum diameter BAT action to get enough barrel steel around the chamber.
And when it was all completed and tested, every number hit right on the money.
I did not just neck up wssm brass and waste it in undersize actions, at ever dumber pressures(like most who've failed with this cartridge).

You make good points that most of my loads are lower in pressure than SAAMI max, and that my cartridges are relatively smaller than many hunting cartridges.
But it's all a matter of choices, and that's my point.
If you choose a 30-06, you're choosing FL sizing. If you choose a 30SAUM, or 30WSM & set it up right, well then there are other choices about sizing, that can be made right up front.

 

[Bart B]

Will these issues of full length versus any other way ever end?????? Prolly not.

Sierra Bullets has been full length sizing their fired cases used to shoot their bullets for quality control since the 1950's. I doubt anyone shoots 'em any more accurate than they do. Nowadays, they use Redding full bushing dies for cases they're made for, standard Redding dies for all the rest.

Benchresters pretty much moved from neck only to full length sizing with bushing dies not too many years ago. Their smallest groups didn't get any tinier but their largest ones did; by quite a bit, too. So the average group size got smaller.

High power match rifle shooters have been full length sizing their cases for as long as Sierra has. Many tests with these normally shoulder fired rifles clamped in machine rests have produced groups smaller than current bench rest records.

Minimal fired case sizing helps. Don't reduce the fired case body diameter nor set its shoulder back more than 1 or 2 thousandths inch. Use neck bushing dies sized about 2 thousandths smaller than a loaded round's neck diameter.

Choose the tools and procedures your feel most comfortable with. Note that if one doesn't use any set of tools and techniques correctly, it'll not produce acceptable results. Learn how cases exactly fit the chamber when they're fired with and fired case sizing method; that'll help you decide what's best to meet your objectives. Regarding objectives, list them in order remembering if you move a lower placed one up the list, some higher ones above it have to come down.