SB 308 die overworks brass?

[timelinex]

I used a SB 308 redding die to size all my AR 308 brass, since it was military 1x fired. Everything runs great. Now it is coming time to size the brass again to reload and I am wondering if I can use the SB die again or is it not recommended? I know theoretically the less the brass is touched, the longer it lasts. But I want to know if realistically it will be make a difference in the end. I use a light load of 43.6gr behind 168smk and I won't lose too much sleep if I only get 9 reloads instead of 10 (but only getting 5 instead of 10 would be a big deal)

The reason I want to use it again is so that I don't have to buy another die or change the position of my other 308 FL die.

 

[ChrisGarrett]

Don't use SB dies if you don't need them, is my suggestion.

I've loaded all manner of mixed stamp .mil surplus brass for 556/762 and I've never had an issue with getting that brass to chamber in any of my commercial chambers and .mil style toys because the brass was too fat. Sure, I had some hard ones to size, but they all sized up using standard sizing dies. And we're talking boxes of M-240 7.62 brass that looked like an inflated rubber.

I picked up a SB 223 Redding body die here off the Hide a few years back, for cheap and loaded up a box of 50 rounds utilizing my Dillon 'sizing toolhead' (body die #3, bushing neck step-down #4, bushing neck final/deprime #1) setup for the first time.

I get out to the range and start popping things off like it's the 4th and when I go to police my brass, there's freakin' soot all the way down the case bodies--each and every one of them.

I was getting major blow back and the only thing that changed over the 16 years of reloading up until that point, was that I used a small base sizing die--in this case a body die for shoulder bumps.

I went to the Redding group buy section and bought a standard 223 body die and things are peachy.

Chris

 

[dauntedfuture]

There are some FL dies that size down as much as a SB die will. The SB die will size the body of the case a little smaller, in theory, than a regular die will. If you are using range pick up or MG brass a SB die is not a bad idea to make sure everything gets down to spec. You can control how far you push the shoulder back with your SB die. You want to make sure that you are sizing the shoulders back .002-.003 after a case has been fired in your rifle. The potential with the SB die is that you work the body of the cases too much; you need to measure a sized and fired-from-your rifle-case and see how much real reduction there is. If the measurements are extreme then you might consider another FL die. I think your primer pockets will wear out or your necks will start to split before excessive body sizing impacts your brass; what will you will see is that you will need to trim a little more often then you otherwise might need to do. Neck reduction and expansion is another matter all together.

 

[Mad_Charlie]

While I have not had exactly the same experience as Mr. Garret, I fully agree with him. I have never needed SB dies, and I too have run into some really "balloony" looking cases.

I would just snag up a regular FL die of your choice and use that and save the SB for when you really need it.

 

[918v]

Your auto loader will do more harm to the brass than the SB die could ever dream of doing.

 

[918v]

While I have not had exactly the same experience as Mr. Garret, I fully agree with him. I have never needed SB dies, and I too have run into some really "balloony" looking cases.

Have you ever reloaded a case more than 5 times?

They work harden at the base. A standard FL die sometimes cannot size the base enough due to spring back. So you have to use a SB die.

 

[DrewC]

It's always an argument on small base vs standard full size dies and I don't understand why you wouldn't want to size the brass back to "virgin"spec, especially if it's for auto loaders. I know people that just bump this and size that then have a bunch of rounds marked for certain rifles only - drives me nuts! In my experience I toss brass due to the primer pockets getting too loose and never lost any due to brass being over worked by sizing. I was talking to one guy that insisted to only use standard full length dies and small base is terrible (over works your brass dude he'd say getting all worked up) and the look on his face when I told him his Dillon sizing die is a small base... Yeah...

 

[ChrisGarrett]

It's always an argument on small base vs standard full size dies and I don't understand why you wouldn't want to size the brass back to "virgin"spec, especially if it's for auto loaders. I know people that just bump this and size that then have a bunch of rounds marked for certain rifles only - drives me nuts! In my experience I toss brass due to the primer pockets getting too loose and never lost any due to brass being over worked by sizing. I was talking to one guy that insisted to only use standard full length dies and small base is terrible (over works your brass dude he'd say getting all worked up) and the look on his face when I told him his Dillon sizing die is a small base... Yeah...

I don't worry about it over working my brass in the least bit. I worry that it squeezes my case bodies in so far, that gas blows all the way towards the head of the case.

That's gas that's not pushing the bullet down the bore, in my estimation.

I'll be the first to say that I'm not a 'small base die' reloading expert, but the one time that I used one, I had a lot of soot in places that I should not have had soot.


Chris

 

[Mad_Charlie]

Oh yeah, but only if they have mostly fired with moderate loads otherwise I loose pockets first

 

[dauntedfuture]

I cant measure a case at the moment, but the smallest a case if going to be is when its a virgin case. I don't think you're going to get it smaller even with a SB die. Reference gas blow back; that only happens if your powder is too slow for your bullets like 4895 with 125g in a .308, your cases will come out smokey but its only a little gas.

 

[918v]

I don't worry about it over working my brass in the least bit. I worry that it squeezes my case bodies in so far, that gas blows all the way towards the head of the case.

That's gas that's not pushing the bullet down the bore, in my estimation.

I'll be the first to say that I'm not a 'small base die' reloading expert, but the one time that I used one, I had a lot of soot in places that I should not have had soot.


Chris

That's cuz your pressure too low.

 

[sinister]

If once-fired .mil brass works in your rifle using just a full-length die I'd say you have no problems, period.

If you load once-fired .mil brass and you have a bitch of a time turning down a bolt handle, you can't chamber a round without pushing hard, you get a slam-fire, or you have problems extracting and ejecting you may need to small-base size.

You may only need to small-base size for the first chambering and shooting in your rifle(s), then use a standard FL die forever after that.

First-fired surplus brass is a fantastic cost-cutting measure, but never sacrifice economy for safety.

 

[ChrisGarrett]

That's cuz your pressure too low.

No, it's not because my pressure was too low, it's because I shrank the case bodies down well below their ability to expand the distance needed to seal off the chamber. I've loaded low pressure rounds before and I know the signs.

This was a small base die squeezing the brass down too far for the pressure of my rounds, which weren't low pressure loads to begin with, IMO, but I'd have to search out that data to be sure.

Now...to your point, I might have loaded something hotter, that might have done a better job of stretching the brass beyond the point that this combo stretched it, or I could have shot the rounds out of a tighter match chamber (this was a BM 20" 1:7" .gov profile 556 chamber) and experienced a better job of sealing, but this has never happened to me, like this (45 out of 50?) ever before (and I have an HK-91 lol) and the only new variable was the small base body die.

Brass is elastic up until a point and then it ceases to be so. It's not as elastic as a rubber band, or the stuff your underwear uses.

I have no problem breaking out that small base die for brass that's really ballooned, but my point is is that IME, one doesn't generally need to use a small base die, even for .mil surplus brass, if they're not shooting a tight match chamber and/or that brass isn't fired out of a truly sloppy .mil chamber.

Chris

 

[4Quangs]

Chris: "No, it's not because my pressure was too low, it's because I shrank the case bodies down well below their ability to expand the distance needed to seal off the chamber."

The SB die differs from a standard FL die only in the lower 1/2 inch (the base) or so of the case. That is, the SB die is no different than an FL die in any other respect.

On all cases, the powder residue is seen on the outside of the neck, but not on the shoulder or case walls. It is the case shoulder and upper case walls that effectively seal off the gas, not the base of the case.

I would expect the case to fragment when the round is shot if wasn't supported by the chamber itself. The potential 50K PSI is just too much pressure for the case to handle on its own.

 

[ChrisGarrett]

Chris: "No, it's not because my pressure was too low, it's because I shrank the case bodies down well below their ability to expand the distance needed to seal off the chamber."

The SB die differs from a standard FL die only in the lower 1/2 inch (the base) or so of the case. That is, the SB die is no different than an FL die in any other respect.

On all cases, the powder residue is seen on the outside of the neck, but not on the shoulder or case walls. It is the case shoulder and upper case walls that effectively seal off the gas, not the base of the case.

I would expect the case to fragment when the round is shot if wasn't supported by the chamber itself. The potential 50K PSI is just too much pressure for the case to handle on its own.

Thanks for the reply. As I said, I'm no expert on small base dies, but I've never seen any specs in writing, mentioning only the bottom half inch being 'squeezed in' more than the rest of the case body proper.

My point was that in my one experience shooting brass out of a 'probably' generous 556 BM chamber, which was sized using a SB die, showed that gas was migrating down most of the case body proper. I didn't bother to photograph those cases so I could post them in a thread on the topic, but it was a one time experience and it's never happened before. I do have a lot of rounds down that barrel and I'm a reloader who plays with a lot of combinations for any weapon, so I would think that the problem would have manifested itself, somewhere down the road over the years and it hasn't.

I'm well aware how to mitigate gas blow-by on the necks, but letting them grow a bit longer, so I'm not a novice on that front.

As I've said, the sample size was small, but almost the entire box exhibited this phenomenon, so it wasn't like I had 5 out of 50 doing this.

Anyhow, there seems to be a tendency to recommend SB dies for any .mil surp brass and I don't think that SB dies are always warranted, is all.

Take care, Chris

 

[918v]

Your pressure was too low.

 

[M40_A1]

Your pressure was too low.