small base die brass life

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dyl

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Happy Easter!

Anyone have any anecdotes about how long their brass lasts using small base dies versus regular resizing dies? I understand the theory that the more you work / work harden the brass the fewer firings you'll get out of it. This is in regards to a 300 blackout AR pistol. I only have a small base resizing die. I don't want to get into annealing, and would also like to avoid buying another die if it's only going to make a difference in a couple firings.
 
In my experience

work hardening affects the neck and shoulder far more than the web of the case.
The small base die will have no appreciable effect on case life.
 
Small base dies typically size the case web (pressure ring) near its base more than necks and shoulders. That's why it's called a small base die. And they shorten case life.

Excessive sizing rarely, if ever, weakens the neck and shoulder area.

I've got over 40 reloads per 308 case full length sizing them without any annealing. Others over 50.
 
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The answer will depend on the case. If it is harder brass to start with, like LC, the life-shortening will be more pronounced. I can't give you a number because that depends on your chamber dimensions as compared to the die dimensions and how smooth the chamber finish is and it depends on how warm your loads are. My advice would be not to buy a second die at this point in time, but rather to segregate out a small number of cases and shoot them until they show incipient head separation or a detectable dip on the inside near the head when you probe them with a paperclip hook. That will tell you how many loads your are getting and you can decide whether it is too few or not.
 
In my experience

work hardening affects the neck and shoulder far more than the web of the case.
The small base die will have no appreciable effect on case life.
 
Thanks fellas,

When I searched around on the internet, I was surprised to find that there wasn't a lot of hard data, probably because of the variables that UncleNick mentioned.

My advice would be not to buy a second die at this point in time, but rather to segregate out a small number of cases and shoot them until they show incipient head separation or a detectable dip on the inside near the head when you probe them with a paperclip hook. That will tell you how many loads your are getting and you can decide whether it is too few or not.
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I actually have that condition currently- I only have about 40 or so 300 blackout cases, having only bought 1 factory ammo box and the rest of the cases were (painfully) converted using a dremel or pipe cutter, then the lee cutter/case holder which is slow and unsteady. I'm still in the load development phase so I don't shoot large quantity yet. Since it was a pain to create these cases, I feel a loss every time I can't find one at the range.

So here's what I'll probably do. Buy some cases or buy a Harbor Freight mini chop saw. But I'll keep using the batch I have (I'm on the the 4th-5th firing) and keep an eye on them until they show too much wear and tear. If I get more than 10 firings, I think I could be happy. Okay maybe 15 and I'll be happy.

I've got over 40 reloads per 308 case full length sizing them without any annealing. Others over 50.
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Wow. I never would have thought that possible.
 
Hmmm ...

Bart B. said:
Small base dies typically size the case web (pressure ring) near its base more than necks and shoulders. That's why it's called a small base die. And they shorten case life.

Excessive sizing rarely, if ever, weakens the neck and shoulder area.
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vs.

jcj54 said:
work hardening affects the neck and shoulder far more than the web of the case.
The small base die will have no appreciable effect on case life.
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This may be the first Internet discussion I've ever subscribed to.
 
There's been many instances of 7.62 NATO M118 match ammo fired in 30-06 M1 rifles. After seeing fired no-neck/shoulder cases from them on the ground, I've told the shooter to cease fire and unload the round he just loaded from his Garand then give that round to me.

The 7.62 round had scrape marks back from the shoulder a bit where it got squeezed down by the 30-06 chamber body. The 7.62 round was wedged in tight enough to hold the case so the extractor claw would slide over the case rim to pull the fired case out of the chamber. It's possible the chambered 7.62 round would be driven a few thousandths deeper into the chamber by the firing pin forces before the round fired.

Post #30 in this thread has a picture of one. The scratch marks on its body behind the shoulder are seen.

https://thefiringline.com/forums/showthread.php?t=478820&page=2

Read post #32 in that link.
 
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Aguila Blanca said:
Hmmm ...

This may be the first Internet discussion I've ever subscribed to.
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It may well be the same as challenging members of The Flat Earth Society that the earth is round, not flat.

There are a few such "societies" in the shooting sports.
 
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Read the USN report on chambering 7.62 NATO ammo in 30-06 Garand chambers. There's a .008" interference fit at the case body where the shoulder tapers down to the neck.
 
OP I agree with Unclenick that you should just use what you have and monitor closely but may I ask . Do you even need a small base die ? Many times you just need to use them once to get the case base back small enough to chamber in your rifle . You then should be able to use a standard die .

I shoot once fire LC brass in both 308 and 5.56 . I also have small base dies for both and load for many different rifle in both calibers . To date and several thousand cases in both calibers I've only needed the small base die once . OK 500 times but that was one lot of brass 500ct that had the case bodies blown out from being fired in a full auto NATO chambered rifle . My standard die works fine with those cases now .

Bart B said:
Excessive sizing rarely, if ever, weakens the neck and shoulder area.
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First may I ask what's your definition is of weakens as it relates to firearm cartridge brass ? Does "weaken" mean softer or does it mean harder or does it mean does not effect the strength enough in any way to cause failures ?

Second where those cases you sized 40+ times sized with a custom die that was more less best fitted to the chamber the brass was to be fired in ? Or were the dies used standard factory die for use in a factory chamber/barrel . Meaning not a rifle picked out special from the armory that was best of the rest . Talking standard factory die with standard factory chamber

I ask the second because I have a factory Redding FL sizing die that sizes the inside of my case neck from .314 ( fired ) to .297 (before expander) then back to .306 after expander is pulled through . That's a whole lot of movement if you ask me . Are you saying that much movement will not effect the work hardening of my brass or just that it wont weaken it enough to cause failures no matter if I size it that way with that much movement over 40 times ?

I anneal after the 4th or 5th firing so I never get to the 40th firing to see what would happen . I can say It sure seems to effect bullet hold and seating force the more times I size the cases to include more spring back of the shoulder the more times the case is sized with out annealing . Maybe the case stops getting harder at the 10th , 15th , 20th, sizing ? I'm not sure I've never sized one case that many times with out annealing so I have no reference .
 
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When the 300 BO first came out, as I recall there was little to no commercial brass initially available so you had to trim and size 223/5.56 brass. That involved necking down of the trimmed case.
 
Metal god, answers to your questions.......

May I ask what's your definition is of weakens as it relates to firearm cartridge brass ? Does "weaken" mean softer or does it mean harder or does it mean does not effect the strength enough in any way to cause failures ?
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Weakens means work hardening making the brass brittle the same way it happens at the pressure ring near the extractor groove.

Second where those cases you sized 40+ times sized with a custom die that was more less best fitted to the chamber the brass was to be fired in ? Or were the dies used standard factory die for use in a factory chamber/barrel . Meaning not a rifle picked out special from the armory that was best of the rest . Talking standard factory die with standard factory chamber
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Standard RCBS full length sizing dies whose necks are honed out to about .002” less than a loaded round’s neck diameter. Hart barrel had a SAAMI spec standard chamber.

I ask the second because I have a factory Redding FL sizing die that sizes the inside of my case neck from .314 ( fired ) to .297 (before expander) then back to .306 after expander is pulled through . That's a whole lot of movement if you ask me . Are you saying that much movement will not effect the work hardening of my brass or just that it wont weaken it enough to cause failures no matter if I size it that way with that much movement over 40 times ?
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My dies have the decapping expanding stuff removed. Minimal working of the brass. Fired cases were decapped and cleaned before they were reloaded. All the case dimensional changes your stuff goes through is 2 to 3 times as much as mine.

I anneal after the 4th or 5th firing so I never get to the 40th firing to see what would happen . I can say It sure seems to effect bullet hold and seating force the more times I size the cases to include more spring back of the shoulder the more times the case is sized with out annealing . Maybe the case stops getting harder at the 10th , 15th , 20th, sizing ? I'm not sure I've never sized one case that many times with out annealing so I have no reference .
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I’ve never annealed a case neck. A friend used the die I honed out then shot 56 Sierra 168’a from his 308 match rifle clamped in a machine rest using one Federal case. Extreme spread group at 100 yards was 3/8 inch. No annealing.
 
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Full length sizing dies with bushings are not custom and commercially available. They do the same thing.
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No they don't , they have the potential to do the same thing but it's not universal . The fact my "factory" barrels blow out ( allow to expand ) my necks so much . My bushing dies actually force them into an hourglass shape if the expander is not used because they are sized down so much . This was confirmed to happen when sizing a neck down more then .006 in an email exchange with Redding

Not sure why my photos have been removed from this thread but hers one example
https://thefiringline.com/forums/showthread.php?t=567609
yoVIFC.jpg



Standard RCBS full length sizing dies whose necks are honed out to about .002” less than a loaded round’s neck diameter. Hart barrel had a SAAMI spec standard chamber.
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A die with any modification or custom made to match a chamber or case is not a standard die and IMHO can only be described as custom . The heart barrel is not standard unless you are saying Savage , Remington , CZ etc are now installing Heart barrels on there factory rifles . That is an after market part likely with it's chamber custom cut . Maybe with in SAAMI specs but none the less custom cut or cut to minimum SAAMI spec .

Of course my definition of factory and standard may be different then yours . When I say standard it means no different then any other factory mas produced product that manufacture makes and anyone can buy them in bulk in just about any store . With out specifying any difference then what the manufacture makes as there standard product .

Example

A standard shell holder has a deck height of .125" . The Redding competition shell holders although may be considered Reddings standard comp set they are not standard shell holders because each shell holder in the set has a different deck height .

Yes one could argue that a chamber cut with in SAAMI spec regardless of tightness or looseness is standard . I think we know that is misleading in the context in this thread . It's seems these days I'm seeing more and more factually accurate posts but way out of context of the question being asked . The OP is shooting a semi auto , likely AR platform . Are you really saying he should get "at least" 40 and maybe as many as 56 loadings with his brass or are your original comments out of context because you were talking about custom components that don't directly relate to the OP's firearm or reloading components ?
 
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I have one chamber neck area that is .009 larger then my loaded neck diameter which result in my neck being sized down with a standard die .014+ before being expanded . With my bushing die I can reduce that movement to about .008 to .009 but with out the expander being used I get those hourglass necks .

the craziest thing about those hourglass necks is the mouth area is sized to the same size as the bushing but some how the thinner center section is sized down smaller then the bushing used . This does not even seem possible but Redding confirmed this can and does happen .
 
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I had to go to small base in .223 as my Lee set was a TEENY bit wide for civilian chambers...I have not seen any appreciable difference in case life at all. However, I just started doing that a couple of years ago and I have a lot of brass to work through.
 
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