How critical is case capacity?

pickpick

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I just loaded some 243win with 39.5 and 40.0 of varget behind 90gr nosler bt. I'm reloading for my dpms 20" upper 1-10 twist. I noticed that the case wasn't as full as I'm used to seeing when loading other calibers. Is case "fullness" a critical point in reloading? Thanks.
 

Victor N TN

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Re: How critical is case capacity?

Most gun writers say that 80% or better fill is a good thing. Keeping the powder against the flash hole will help the powder collumn burn better. But the right powder is the key. Pay more attention to the target and what kind of groups you're shooting. Adjust your powder charge accordingly. You'll get it there.
 

Fuzzball

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Re: How critical is case capacity?

"Is case "fullness" a critical point in reloading?"


What you're speaking of is "loading densisity", relating to how full the case is to the base of the seated bullet. No, withing rational limits, it isn't "critical". But, if there is a LOT of empty space it has been reported to end up with a KABOOM due to several factors. Just keep it at 80% or more and you'll be fine, at least IF your chosen powder has the proper burn rate.
 

Fuzzball

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Re: How critical is case capacity?

"Is case "fullness" a critical point in reloading?"


What you're speaking of is "loading density", relating to how full the case is to the base of the seated bullet.

No, withing rational limits, it isn't "critical". But, if there's a LOT of empty space it has been reported to end up with a KABOOM due to several possible factors. Make it simple, just keep loading density at 80% or more and you'll be fine, at least IF your chosen powder has the proper burn rate for the case and bullet weight.
 

Grump

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Re: How critical is case capacity?

It's important enough that if your favorite charge weight is coming up further to the shoulder or the neck of some different batch of cases, that load might not be safe any more.

That depends most on how close to max you are in the first place, and to a lesser degree on what powder and bullet you are using. It's all more or less in general, but quite reliably in the direction of less case capacity = higher pressure. Lose enough case capacity, and you won't be able to match top safe velocities you might have been getting from a more spacious case. That's why we have Magnums with bigger cases, instead of just upping the pressure until we get the desired higher velocity.
 

Clark

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Re: How critical is case capacity?

Not everything in load books is wrong, but mostly.

Blue Dot powder in .223 for shooting ground squirrels allows 100 shots per hour without the barrel heating or fouling.

The BIG problem with Blue Dot in 223 is that it sometimes hangs in the powder measure AND the desired charge does not fill the case.
13 gr is 60% fill ratio
15 gr is 70% fill ratio

This means that sometimes there could be light charge on one round and a heavy charge on the next.

This requires some diligence to avoid. The charged cases must all be checked to have approximately the correct fill.

18 gr of Blue Dot in a .223 is 84% and anything more than that can make the primer pocket double in diameter.

What does it all mean?
Loading cases with low fill ratio loads with powder than can stick is advanced reloading, so don't let your kids do it.
 

BobinNC

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pickpick</div><div class="ubbcode-body">I just loaded some 243win with 39.5 and 40.0 of varget behind 90gr nosler bt. I'm reloading for my dpms 20" upper 1-10 twist. I noticed that the case wasn't as full as I'm used to seeing when loading other calibers. Is case "fullness" a critical point in reloading? Thanks. </div></div>

Your questions regarding case capacity and "fullness", seem to have been answered.

However, I have a question for you:

Are you aware that Hodgdon's max load of Varget for a 90 gr bullet is 36.5 grains?

I've gone over book max with loads before, but always from below. So I hope you've worked up to the 39.5 and 40.0 grain levels from below; just saying.........

Bob
 

pickpick

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BobinNC</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pickpick</div><div class="ubbcode-body">I just loaded some 243win with 39.5 and 40.0 of varget behind 90gr nosler bt. I'm reloading for my dpms 20" upper 1-10 twist. I noticed that the case wasn't as full as I'm used to seeing when loading other calibers. Is case "fullness" a critical point in reloading? Thanks. </div></div>

Your questions regarding case capacity and "fullness", seem to have been answered.

However, I have a question for you:

Are you aware that Hodgdon's max load of Varget for a 90 gr bullet is 36.5 grains?

I've gone over book max with loads before, but always from below. So I hope you've worked up to the 39.5 and 40.0 grain levels from below; just saying.........

Bob </div></div>

I started at 39.5grains.
http://www.snipershide.com/forum/ubbthre...276#Post1859276
 

arborpro

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Re: How critical is case capacity?

l also use the 85% solution (using the water capacity method) for loading in conjunction with a loading manual. I look for a powder that yields the best velocity that is closest to my 85% figure. not just any powder that will fill 85% of the case. remember some manuals will list pressure and some show max velocity. that is because the velocity that is listed is at max safe pressure.

Arborpro
 

jrob300

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pickpick</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BobinNC</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pickpick</div><div class="ubbcode-body">I just loaded some 243win with 39.5 and 40.0 of varget behind 90gr nosler bt. I'm reloading for my dpms 20" upper 1-10 twist. I noticed that the case wasn't as full as I'm used to seeing when loading other calibers. Is case "fullness" a critical point in reloading? Thanks. </div></div>

Your questions regarding case capacity and "fullness", seem to have been answered.

However, I have a question for you:

Are you aware that Hodgdon's max load of Varget for a 90 gr bullet is 36.5 grains?

I've gone over book max with loads before, but always from below. So I hope you've worked up to the 39.5 and 40.0 grain levels from below; just saying.........

Bob </div></div>

I started at 39.5grains.
http://www.snipershide.com/forum/ubbthre...276#Post1859276
</div></div>

So... you haven't fired these loads yet?

I wouldn't, but that's just me. Starting almost 3 grains over book max. (assuming Bob is correct.. and he usually is) is inviting DISASTER, I don't care who else is running the load.

Disciplined and responsible reloading mandates that you learn YOUR weapon, and that means starting under book and then work up til you see pressure signs and back off to the last accuracy node (one method).

I've had weapons that were able to load 2 gr over max. but I understood WHY.

If you've been reloading for thirty years and you have a buddy that has a rifle just like yours, built with exactly the same components and chambered with the same reamer by the same gunsmith, you *might* be able to justify some shortcuts.

But barring that, you really have no good logical basis to predict that load will not put the bolt through your cheekbone.

Perhaps I'm being melodramatic, or maybe I like to live and have gotten conservative with age.

Do yourself a favor, do it the long way, write everything down and prove me wrong. But you'll have some good data and may have dodged a bullet (no pun intended).

John
 

Clark

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrob300</div><div class="ubbcode-body">

I wouldn't, but that's just me. Starting almost 3 grains over book max. (assuming Bob is correct.. and he usually is) is inviting DISASTER, I don't care who else is running the load.

</div></div>

Hodgdon data is shit.
I have not found any exceptions to that, and I load over 60 different cartridges.
They re-sell some great powders, but their data is shit.

Crappy Hodgdon Data for 243, Varget, and 90 gr bullet:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">36.5 3106 50,400 CUP </div></div>

When I put 40 gr Varget and 90 gr Nosler into Quickload, I get less than 60 kpsi.

That would be a good starting point to work up from in a 243.

The 243 uses the 1889 7.65x53mm Mauser case head design built with a Large Boxer primer pocket.
Such case heads are good for ~65kpsi [Quickload predicted] long brass life, no matter what capricious pressure was registered with SAAMI for any cartridge with that case head.
 

BobinNC

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrob300</div><div class="ubbcode-body">

I wouldn't, but that's just me. Starting almost 3 grains over book max. (assuming Bob is correct.. and he usually is) is inviting DISASTER, I don't care who else is running the load.

</div></div>

Hodgdon data is shit.
I have not found any exceptions to that, and I load over 60 different cartridges.
They re-sell some great powders, but their data is shit.

Crappy Hodgdon Data for 243, Varget, and 90 gr bullet:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">36.5 3106 50,400 CUP </div></div>

When I put 40 gr Varget and 90 gr Nosler into Quickload, I get less than 60 kpsi.

That would be a good starting point to work up from in a 243.

The 243 uses the 1889 7.65x53mm Mauser case head design built with a Large Boxer primer pocket.
Such case heads are good for ~65kpsi [Quickload predicted] long brass life, no matter what capricious pressure was registered with SAAMI for any cartridge with that case head. </div></div>

Clark,

Your post is the irresponsible piece of bullshit I've ever seen posted. Do you realize how friggen many newbee reloaders read these posts?

There is not one reloading manual that lists 40 grains of Varget and a 90 grain bullet in a .243 as a safe load. Not Barnes, Nosler, Hornady, Speer, nor Hodgdon. The max I could find was Nosler at 39.5 grains, as a MAX load.

As far as Quickload goes, it is only a tool. A good tool yes, but just a tool, and no substitute for brains.

I've been reloading for forty years, I know what works, and what does not. There is not a thing wrong with going over book max with a load, IN YOUR OWN RIFLE. But always from below. Telling the pilgims to start @ 40 grains because your Quickload said it is alright is grossly irresponsible, and stupid.

Bob
 

Clark

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BobinNC</div><div class="ubbcode-body">
Clark,

Your post is the irresponsible piece of bullshit I've ever seen posted. Do you realize how friggen many newbee reloaders read these posts?

There is not one reloading manual that lists 40 grains of Varget and a 90 grain bullet in a .243 as a safe load. Not Barnes, Nosler, Hornady, Speer, nor Hodgdon. The max I could find was Nosler at 39.5 grains, as a MAX load.

As far as Quickload goes, it is only a tool. A good tool yes, but just a tool, and no substitute for brains.

I've been reloading for forty years, I know what works, and what does not. There is not a thing wrong with going over book max with a load, IN YOUR OWN RIFLE. But always from below. Telling the pilgims to start @ 40 grains because your Quickload said it is alright is grossly irresponsible, and stupid.

Bob

</div></div>

Just trying to get to the truth, Bob.
 

Talljess

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Re: How critical is case capacity?

So should just fill all my cases to the neck and ram the bullet in right..

I am running some decently hot loads. Quick load is great but there isnt anything that beats testing in a manometric barrel
 

kyreloader

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jrob300</div><div class="ubbcode-body">

I wouldn't, but that's just me. Starting almost 3 grains over book max. (assuming Bob is correct.. and he usually is) is inviting DISASTER, I don't care who else is running the load.

</div></div>

Hodgdon data is shit.
I have not found any exceptions to that, and I load over 60 different cartridges.
They re-sell some great powders, but their data is shit.

Crappy Hodgdon Data for 243, Varget, and 90 gr bullet:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">36.5 3106 50,400 CUP </div></div>

When I put 40 gr Varget and 90 gr Nosler into Quickload, I get less than 60 kpsi.

That would be a good starting point to work up from in a 243.

The 243 uses the 1889 7.65x53mm Mauser case head design built with a Large Boxer primer pocket.
Such case heads are good for ~65kpsi [Quickload predicted] long brass life, no matter what capricious pressure was registered with SAAMI for any cartridge with that case head. </div></div>

Complete irresponsible garbage!

Hodgdon lists 58.5g of H1000 as max load with 117g bullet in .25-06. I loaded starting at 55g with a 115g bullet. When I got to 58g in MY rifle, the first shot read 3246 fps on the chrony with a smoked primer; the second 3254 fps with a blown primer.

I guess Hodgdon data might not be shit afterall.

Very irresponsible to recommend starting at a over max load with any load irregardless of what you THINK you know.

Each rifle/chamber/barrel is different and needs to be treated as such.
 

jrob300

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Re: How critical is case capacity?



Clark,

Belittling your fellow posters is not the way to convince us of your wisdom.

Having been an engineer for close to 25 years, and knowing how much design margin is built into most products and processes, and then gleefully exploiting them for my own gain, I understand that you may live life on the ragged edge (from others perspective) but feel quite comfortable.

Having said that, I agree that this is a very irresponsible and slapdash way for you to present your findings and could potentially cause this site liability issues. I'm a little surprised a mod hasn't stepped in on this, as there is a BIG warning in the reloading section (perhaps they feel this is enough CYA).

Every publication from credible sources encourages safe reloading practices, which involve starting low and working up. You may have a valid point about pressures, but the reason some factory loadings are soooo conservative, is because of some actions out there that are really old and not very strong. What happens when your advice intersects one of those actions? Granted .243 is probably not on that list, but are you willing to personally take responsibility for EVERY person who reads your post and then uses those numbers? Are you SURE that those numbers will be safe, IN EVERY ACTION UNDER EVERY VARIABLE, UNDER ALL CONDITIONS?

An engineer that worked for me and did such a thing would be strongly reprimanded, which you have been, or perhaps even fired.

John
 

FreshKills

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pickpick</div><div class="ubbcode-body">I just loaded some 243win with 39.5 and 40.0 of varget behind 90gr nosler bt. I'm reloading for my dpms 20" upper 1-10 twist. I noticed that the case wasn't as full as I'm used to seeing when loading other calibers. Is case "fullness" a critical point in reloading? Thanks. </div></div>

I typically like to eliminate airspace,as a means of consistent ignition/velocity.

The exception is typically Re-15,which I don't fret nearly as much as most.
 

Clark

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Re: How critical is case capacity?

Straightening out this thread has been a hassle for me.
I had lots of confidence in Quickload, none in Hodgdon data, but I had never opened my pound of Varget and verified that the characterization in the Quickload library was accurate.
Also, I am not a 243 person.


Mauser2431903TurkABF54barrel10pound.jpg


I had to pull rifle from storage. I started building this rifle for the daughter of a US soldier in Iraq in May 2008. While I had never met these people, it became evident through email that the girl could not handle an 11.5 pound rifle, so I built her an ultra light 243, and put this rifle in storage.
Yesterday, I had to deal with the chamber being .001" too short headspace and re cut the chamber and clean it out.
I had to deal with the Partner press would flex, and other presses and some dies did not want to push shoulder back. I used the Lee #3 shell holder, RCBS FL die with no stem, and way over toggled the Partner to get the die to touch the shell holder so the case would chamber.

1903 Turkish Mauser built at Oberndorf Germany between 1903 and 1905, 24" barrel
A&B F54 moly chrome barrel 243 short chambered large ring, I re-cut threads for small ring.
standard 243 reamer, chamber neck is a go with .277" pin gauge , which is minimum.
Bolt closes on headspace go gauge with slight increase in bolt handle force
With bullets seated at 2.71", chambering and ejecting cartridges, it looked like ~ .1" of lands marks on the bullets.
So I backed off on the seating length to ~ 2.6" so the bullet would be ~ ~ .010" off the lands

I fired (3) shots:
a) 42 gr Varget
.912" length 87 gr bullets
2.6" OAL, .405" extractor groove
Quickload predicts 66 kpsi
no egg (extractor groove growth)
spent primer hard to de cap

b) re used same case
43 gr Varget
.912" length 87 gr bullets
2.58" OAL, .405" extractor groove
Quickload predicts 72 kpsi
no egg (extractor groove growth)
spent primer hard to de cap

c) re used same case
44 gr Varget
.912" length 87 gr bullets
2.595" OAL, .405" extractor groove
Quickload predicts 77 kpsi
.001"egg (extractor groove growth)
spent primer easy to de cap

This was to compare to a hypothetical 90 gr Nosler 40 gr Varget 243 load:
OAL = 2.35" predicts 71kpsi
OAL = 2.71" predicts 60 kpsi

Hodgdon data 36.5 gr 2.65", they claim is 50,400 c.u.p, while Quickload predicts 47, 816 psi

What does it all mean?
a) It is typical for primer pockets to loosen when Quickload predicts the pressure to be in the 70~80 kpsi region for the large Boxer primed 1889 case heads used in 22-250, 243, 6mm Rem, 250 Savage, 257 Roberts, 25-06, 260 Rem, 6.5x55 [US brass], 270, 7mm-08, 7x57mm, 280, 300Sav, 308, 7.62x51mm, 30-06, 8x57mm, 338F, 358, and 35W.
I had previously verified that for powders like IMR4895 and H4350, but it is good to see it is true for Varget as well.
b) I verified that the subject 90 gr Nos 40 gr Varget load for 243 has safety margin between it and short brass life.
 

jrob300

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Re: How critical is case capacity?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">I verified that the subject 90 gr Nos 40 gr Varget load for <span style="color: #FF0000">one </span>243 has safety margin between it and short brass life.
</div></div>

John
 

HOGGHEAD

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Re: How critical is case capacity?

The two things I look for first when picking a powder is how close to a full case is the load I am expecting to be a good load. And also selecting a powder that is the least temperature sensitive of the best powders that yield close to or full case capacity.

IMO the key to an accurate load is the lowest standard deviation you can acquire for certain powder, charge and bullet. It is pretty much standard that the lowest S.D.'s are normally going to be your most accurate load. IMO this is the best use of a chronograph. I do not actually use the velocity from the chronograph to calculate my trajectory. I always shoot my rifles to determine the exact trajectory at each range. But I will also admit the my normal longest distances that I can shoot competently is 700 to 800 yards.

A lot of guys try to use a powder that yields the most velocity with the least amount of powder burned. They do this to save money on powder. Rarely have I seen a load like this to be the most accurate, and normally has the highest S.D.'s at the range. Tom.
 

Grump

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Re: How critical is case capacity?

Looks like many posts after 6/8/10 at whatever a.m. missed the following which pickpick linked to:

"Thanks folks. I loaded some 90gr nbt over 39.5 and 40.0 of varget with cci primers. It didn't group well at all. But, the case might have only been 60% or so full. I didnt have any signs of pressure, so I'll start 2 grain increment loads on up. Thanks for all the help."

He apparently hadn't yet fired the proposed test loads in the first post.

QuickLOAD is pretty good, but MUST IMNSHO be calibrated with the actual rifle's case capacity per the instructions, AS A MINIMUM. Nevertheless, mathematical modeling sometimes gets it wrong. Question and the critical element is by how much?

Clark makes a credible argument for having identified the 77KPSI or so brass flow point in one rifle. Doesn't always transfer to the next one. I knew of two S&W .357 Mag revolvers that shot something like 100 fps different, with corresponding differences in loads being okay in one showing trouble signs in the other. But what cheeses me in this thread is the irresponsibility of tossing about CUP and Piezo PSI numbers as if they are interchangeable. QuickLOAD to my knowledge reports ONLY piezo equivalent PSI. The best I can say is keep it caliber-specific for max loads only, compare the official specs for both methodologies before you start saying your QuickLOAD *predictions* are accurate.

I'm participating in this thread hijack because of the importance of the topic.

FWIW, in two .308 barrels, I've had only two powder/bullet combos EVER show higher velocity and pressure indications than "the book/books" said I should be getting. The rest of the time, they have been slower. The last time, both the Hodgdon data and the QuickLOAD predictions had me testing loads something like 2 grains less than max, which were shooting faster than the max loads predicted for that barrel* and which flattened primers enough to make me stop after the third shot.

I think the original poster is a big boy and knows the risks. He has also been advised. My advice to him is to ignore loading density with this round of testing, and STOP right away if his velocities are above what the books say should be max speed for that powder, that bullet, and that barrel length. I hesitate to even mention the 25 fps per inch rule of thumb, since there is another 50 fps difference between different barrels factor superimposed on this question.

*30-32-inch barrel performance out of a 22-inch!?!?!?!? It was NOT Hornady Superformance ammo!!! Scary!