best expander die

[buckbeans]

I am loading with a single stage setup for straight wall pistol brass and was wondering which expander die most folks preferred. I am using a lee and thought the effort to expand brass was a bit more than my lyman. Is this my imagination?

[dromia]

For cast boolits for me the the best off the shelf expander die is the Lyman "M " die, If they don't do the size spud I want then I get one of our member machinists to cut me one to size on the lyman design and to fit the Lyman.

[FergusonTO35]

No, its not you're imagination. My Lee expander in 9mm shakes the workbench to death when the case is pulled out of it. Fortunately the Lee Universal expanding die works great, better than any I've ever tried.

Looks like my post showed up after yours and it looked like I was giving you a hard time. Sorry 'bout that!!

[geargnasher]

The Lee Universal Expanding die isn't an expanding die at all, it's a bellmouth die.

For true, straight, accurate, deep enough expansion for cast boolits plus just the amount of bellmouth you want, RCBS cannot be beat with their dedicated expander-only dies for pistol or rifle (different die bodies for pistol and rifle dies). The expander plugs can be had in a variety of special sizes, including a full lineup of "cowboy" expanders for cast boolits in the pistol and some rifle calibers.

I'm slowly replacing of all my Lyman "M" dies in favor of the RCBS.

Gear

[Reverend Recoil]

Redding also makes good expanding dies.

[Kevin Rohrer]

There is no "best" of anything. What I prefer is what comes with the die set I am using, and I don't use dies whose name begins with L-E-E.

[462]

"The Lee Universal Expanding die isn't an expanding die at all, it's a bellmouth die."

I'm sure Lee has made a small fortune by calling their "belling" or "flaring" die an "expanding" die. While some members find that it suits their particular needs just fine, it does not function the same as a Lyman M-die, nor is the end result the same.

On more than one occasion, Gear has spoken very highly of RCBS's new "expanding" dies -- reckon I need to look into them.

[UNIQUEDOT]

On more than one occasion, Gear has spoken very highly of RCBS's new "expanding" dies -- reckon I need to look into them.

Why bother? it can't possibly be an improvement over an (M) die could it? I don't see how anyone could improve something that's already perfected.


There is no "best" of anything.

Yes there is and when it comes to expanders the best is the Lyman (M) die.

[Longwood]

Why bother? it can't possibly be an improvement over an (M) die could it? I don't see how anyone could improve something that's already perfected.



Yes there is and when it comes to expanders the best is the Lyman (M) die.

Track of the Wolf sells expander plugs in some of the cast bullet sizes.

[462]

"Why bother? it can't possibly be an improvement over an (M) die could it?"

We all have our preferred ways of determining that which best suits our particular wants and needs. In the case of an "expanding" die, I've found the Lyman die to be an excellent tool, while the Lee die, by design, lacks the same functionality. Unless I experiment with the RCBS die, I'll never know if the Lyman actually is the best tool for me.

[Le Loup Solitaire]

The Lee universal is a flaring die. The Lyman M die is an expanding die. The "powder through" dies also made by Lee are primarily flare dies as they are not meant to do what an M die does; they flare slightly and deliver the powder into the case. I have not yet had any experience with the RCBS die. As to what is the best...its the one that is doing exactly what you need and doing it well. LLS

[UNIQUEDOT]

Track of the Wolf sells expander plugs in some of the cast bullet sizes.

Are you talking about the expanders for the Lee dies? are they supposed to do the same thing an m die does?


Unless I experiment with the RCBS die, I'll never know if the Lyman actually is the best tool for me.

I suppose so, but isn't it just a copy of perfection?

[Marvin S]

For me the LEE expanded is good in that I just make my own two step expander to replace the original.

[rbuck351]

I have an old Rcbs 38spl expander die body that I use with home made "M" type dies to fit my cast boolits. That die body is so old it's made of aluminum. It works very well and I can cut the plugs to what ever size I want.

[geargnasher]

Why bother? it can't possibly be an improvement over an (M) die could it? I don't see how anyone could improve something that's already perfected.



Yes there is and when it comes to expanders the best is the Lyman (M) die.

I can't tell if that is sarcasm directed at all of those who think the M-die is god's own gift to cast boolit handloaders, or if you really believe it.

If it's sarcasm, don't go telling me Lee makes the best expanders. John Lee wouldn't know what a real expander was if he ate a bowl of them for breakfast.

If you're serious, all I can say is good luck with your lovely Lyman M dies and have a nice day, because it's obvious you know it all and there's nothing anyone can do to help you.

Gear

[taminsong]

I too have a problem with the Lee expander die. Even with the Hornady PTX dies.
Serious problems occurs at 9mm, 40SW and 38Super.

The dies won't expand the brass much that it swages down the cast bullet resulting to keyholing. Best solution that I found was a homemade expander that suits my needs!

I just wish somebody will make a Hornady PTX dies that is like a Lyman M die, somewhat a hybrid of the two design.

[hornady]

Like many things in reloading and casting what works for me may not for another.

The Redding G-RX die is a good example. I shoot a Glock 22, and reload with Lyman dies. The set I have will not size any bulge on 40 cases. I have a friend that ran the problematic case threw his Dillion dies with no problem. So all my 40 Brass now goes threw the G-RX Die.

Back to the Lyman M-die. I cast for four different Rifle caliber’s and use M-dies on each.
I also cast 7 different pistol rounds, but have never seen the need for the M-die or Lee Universal expander Die with my Lyman standard straight wall pistol dies. I have also used Lee dies. I do not like the floating inside expander in Lee Dies, but they two have always had the ability, to go deep enough to insert cast bullets without any shaving of Lead, and they seem too seat well.

So what is the advantage of the M-Die with Straight wall Pistol cases. Granted all my cast pistol bullets are only sized .01 over jacketed caliber. Is there a difference with bullets sized larger, I have run long un trimmed 357 cases threw the standard Lyman expander die, and they cam out with a pretty good flare on them.

[UNIQUEDOT]

I can't tell if that is sarcasm directed at all of those who think the M-die is god's own gift to cast boolit handloaders, or if you really believe it.

If it's sarcasm, don't go telling me Lee makes the best expanders. John Lee wouldn't know what a real expander was if he ate a bowl of them for breakfast.

If you're serious, all I can say is good luck with your lovely Lyman M dies and have a nice day, because it's obvious you know it all and there's nothing anyone can do to help you.

Gear

No sarcasm intended and yes the lee expander is no good for cast bullets. If there is any possible way for anyone to make a better expander plug than an (M) plug please explain the process to me as i just don't see any way to improve on it as it has three steps when it comes to loading cast or you use the two step adjustment for jacketed. I've seen the opinions, but no one has said why they like what they like.

[FergusonTO35]

A forum buddy made me an expander plug for the Lee 9X19 flaring die. haven't had the time to try it on a full box of ammo yet but it works great on the few cases I've tried so far. It resembles the factory expander but with a longer spud. It seems to do a pretty good job of removing the taper so you can install a .358 boolit. I really like my Lee dies but the factory expander plug is pretty useless. It shakes the workbench to death when you pull the case out of it and it doesn't open up the case nearly enough for boolits. I have had excellent success with the universal flaring die, of course it adds an extra step if you're charging with a die.

[Longwood]

Are you talking about the expanders for the Lee dies? are they supposed to do the same thing an m die does?



Right,,,
I bought three different sizes plus a compression plug for less than a 'M' die..
Cheap enough to modify if needed.
So I did,,, my flaring dies is a convenient, powder thru die.

[geargnasher]

No sarcasm intended and yes the lee expander is no good for cast bullets. If there is any possible way for anyone to make a better expander plug than an (M) plug please explain the process to me as i just don't see any way to improve on it as it has three steps when it comes to loading cast or you use the two step adjustment for jacketed. I've seen the opinions, but no one has said why they like what they like.

The goofy steps on the M die is the problem for cast. They work great for jacketed bullets.

To load truly accurate rifle ammo, case neck tension is rather critical, as is not deforming the boolit or the case neck during seating. This is the whole issue with the M expander, it doesn't facilitate either of these things because the design is flawed. I'll explain:

If you use the boolit to stretch the case, you are messing things up, and the M die requires the boolit itself to do the expanding of the neck below the first step in the mandrel. Cast boolits tend to get squished slightly and bent when this happens, and the necks can get bent or deformed too. Only slighly, you can't see the difference, but it's there and it's usually enough to get the boolit started crooked.

Even and consistent case neck tension is the other bugaboo. Getting right at .0015" neck tension on .30-caliber cast boolits seems to work the best for me. One thing I've also noticed is that the brass has a tough time "changing directions" when stretched and compressed. You size the neck down (hopefully no more than needed), then reverse it and expand it back up. To change the shape/size fo the neck the brass must obviously be pushed beyond it's elastic limit. It takes considerable force to reverse the direction the metal moves and expand it, and you want to do this with a steel expander, not the boolit. Thing is, most rifle brass has about a .002-3" elastic limit depending on state of anneal, and the M dies have the "primary" step machined smaller than that. For example the .30 caliber one has a .307/.3105 mandrel and only expands a short part of the case to .3095 at the most after springback. If you're using a .310" boolit, it's having to stretch the .307" part out by forcing the gas check in there, and the brass is right at it's elastic limit. For some cases, it will be beyond the elastic limit, for others even in the same lot maybe not quite up to the elastic limit. Riding this ragged-edge makes for very inconsistent boolit tension, hence the reason I hate the steps. If you're going to make a stepped spud, which is a defective concept, at least make the step only about .0015" or so, so that the brass will be properly stretched and conditioned to function WITHIN its elastic limit when you seat the boolit.

The ideal expander spud for your particular gun and boolit size will work in conjunction with your sizing die. Size the neck down to where the ID is a couple thousandths below the diameter you want it before seating the boolit, then stretch the brass the other way with a good, parallel-sided expander that's the right size to give you about .0015" smaller than your sized boolit diameter after springback. The expander needs to be long enough to pass clear through the neck and expand the whole thing, and expand it straight in line with the rest of the case. It also needs to bell the mouth a bit so you can start the boolit, and this is an often overlooked thing with expanders: If the bell is part of the expander, it will open the mouth the same way all the way around. If you use a Lee Universal expander or one of the really short pistol PTE expanders, the flaring part isn't guided and centered in the neck by the expander mandrel and thus can stretch the mouth of the case more on one side than the other depending on the condition of the brass, which mind you is never as perfect as we'd like it to be. Having the bellmouth shank doing its thing while the expander spud is keeping it centered and piloted the full length of the neck is important. The M die does do this part, but in many calibers they don't bellmouth properly.

Now, "what about the parallel part starting the boolit straight?" you say? If the case neck is prepared to the correct dimension and tension, the boolit will go in there straight, because straight is the path of least resistance. If the boolit is having to stretch the brass past its elastic limit like is usually the case with M dies, it can push it any direction it wants because the resistance is the same, hence crooked cartridges with all sorts of runout and uneven cast neck tension on the boolit. The other thing I don't like about the M die is that after seating the boolit, you have lost fully a fourth of the holding surface of the case neck because you stretched it to the point it barely touches the boolit. If you think about it, that's sort of a dumb thing to do. If you use an RCBS or similar expander on your rifle case necks, they will grab the boolit with equal tension from the gas check to the base of the flare, and the flare takes much less length than the "starter" portion that the M die creates. I realize you don't necessarily have to push the second step very far down into the case, but the way they're designed, most of the time you have to to get the mouth open enough to start the boolit.

So there you go, it's all about proper neck tension, straight necks, and not deforming anything when you seat the boolit because the boolit is only springing the brass open a small amount and staying well within the elastic limit of the brass when seated. You obviously need to co-ordinate your sizing and expanding dies to work the brass a minimum amount, and often you must segregate your brass between rifles if you're really splitting hairs.

Many of you will argue with me on this and say "I've use and M die for 50 years and never had a problem". Well, fine. If you're happy with what you're doing, then it isn't a problem for you. But for some of us chasing accuracy and higher velocities, these things start to really show up, and the M die won't get you there most of the time.

Gear

[.30/30 Guy]

+1 for geargnasher's great post.

I have been slammed in the past for liking the RCBS expander dies.

[UNIQUEDOT]

Right,,,
I bought three different sizes plus a compression plug for less than a 'M' die..
Cheap enough to modify if needed.
So I did,,, my flaring dies is a convenient, powder thru die.

When i went to the sight and looked at them i thought they were way too inexpensive. Don't know how they can offer consistency for that price, but i think i might just try one or two.

[UNIQUEDOT]

Many of you will argue with me on this

Well your post certainly gives a lot of food for thought.

[dragon813gt]

Thank you Gear. That was a very well written and detailed post. I can honestly say I learned a lot and am now better equipped to choose the correct expanding die. I was fooling around with my Lee dies and some cast bullets that were given to me. I wanted to see just how much the bullets were sized down. Sure enough the .359 bullets were sized down to .357. I am still new to loading cast bullets so anything new I can learn is always welcome.


Brought to you by TapaTalk.

[Bullfrog]

No, its not you're imagination. My Lee expander in 9mm shakes the workbench to death when the case is pulled out of it. Fortunately the Lee Universal expanding die works great, better than any I've ever tried.

Looks like my post showed up after yours and it looked like I was giving you a hard time. Sorry 'bout that!!

I had that problem with a die sticking too much and I dusted a little mica powder in it. The kind used on the neck for rifle cartridges. Did the trick.

[Longwood]

When i went to the sight and looked at them i thought they were way too inexpensive. Don't know how they can offer consistency for that price, but i think i might just try one or two.

A CNC lathe can make them automatically with very little operator input.
I have a lathe and could make them, but at the price they are asking, why bother.

[dromia]

I agree with Gears content absolutely on getting the correct tension without resizing the boolit when seating. However i fail to see where the design of the M die is at fault here so long as it is made to the correct dimensions for the cases and the boolit being used.

So is the difference 'tween the RCBS and the Lyman dies one of dimensions rather that design?

I have never see the RCBS die so cannot comment on the design difference between them and the Lyman. I get M die designed spuds cut to the dimensions for my particular boolit case combination and it does work well.

Does the RCBS die have some inbuilt flexibility to allow the diameter variation necessary?

[.22-10-45]

"The goofy steps on the M die..." As good as the Lyman M dies are..they are not perfect. When I was working with .22 cast, I had the grinder operator set up my expander plug in O.D. grinder, & grind step to a 1 to 2 deg. angle..this will bell mouth ever so slightly..can barely see it & eliminates excess working of case mouths. Worked so well, nearly all of my expanders have this.

[singleshot]

So given all this info, what dies would be best for shooting cast boolits in 32 S&W Long, 32 H&R and 327 Federal?

I had a set of dies (Champion, I think) that destroyed a 32 H&R case b/c it was designed for 32 S&W. After it demolished the case, I discovered it had a mouth flare on the sizing and decapping die that could not accomodate the longer brass. Also, the sizing die overworks the brass.

Anyway, the RCBS Cowboy set doesn't say it will do 32 H&R or 327 Fed, only 32 S&W. Will it handle the longer cases? What's a good die set for all 3, or should I buy 2 or 3 different sets?

One of the reviewers on Midwayusa.com said the RCBS die set couldn't deal with 32 H&R starline brass...said it was too thick. What do you guys use?

[1hole]

"..M die requires the boolit itself to do the expanding of the neck below the first step in the mandrel. Cast boolits tend to get squished slightly and bent when this happens, and the necks can get bent or deformed too. Only slighly, you can't see the difference, but it's there and it's usually enough to get the boolit started crooked."

I got my first M die in '65. Added several more since and have turned more since I got a good lathe; my experience has been exactly the opposite for both cast and jacketed bullets and I use them for both types. And others agree with me, last I looked both Redding and RCBS has copied it.

The first part of my M expanders are normal for caliber. The short second step is only a couple-three thousanths larger than proper size bullets to allow the critical heels to enter and start smoothly; it works too. 'Normal' flaring for cast is often much greater than what a properly used M expander does but if actual flaring IS needed it has a step for that too. What's not to love?

Any tiny 'excessive' working of the case mouth is greatly exceeded by the value of better bullet entry and accuracy. And that second step decreases - eliminates - the need to flare case mouths for most cast bullets. It also helps in seating flat based jacketed bullets without heel damage. All bullets can start straighter when the M is used because there is no excess resistance on one side during that first critical entry; it's quite easy for a die's seating throat to align a bullet when it's already a few thousanths inside the mouth.

[FergusonTO35]

geargnasher and others who like the RCBS: are you speaking of the standard expanding/flaring/whatever die that RCBS sells for handgun calibers? If not, which one are you speaking of? I'm looking for the best expander to use .358 boolits in 9X19.

[largom]

The goofy steps on the M die is the problem for cast. They work great for jacketed bullets.

To load truly accurate rifle ammo, case neck tension is rather critical, as is not deforming the boolit or the case neck during seating. This is the whole issue with the M expander, it doesn't facilitate either of these things because the design is flawed. I'll explain:

If you use the boolit to stretch the case, you are messing things up, and the M die requires the boolit itself to do the expanding of the neck below the first step in the mandrel. Cast boolits tend to get squished slightly and bent when this happens, and the necks can get bent or deformed too. Only slighly, you can't see the difference, but it's there and it's usually enough to get the boolit started crooked.

Even and consistent case neck tension is the other bugaboo. Getting right at .0015" neck tension on .30-caliber cast boolits seems to work the best for me. One thing I've also noticed is that the brass has a tough time "changing directions" when stretched and compressed. You size the neck down (hopefully no more than needed), then reverse it and expand it back up. To change the shape/size fo the neck the brass must obviously be pushed beyond it's elastic limit. It takes considerable force to reverse the direction the metal moves and expand it, and you want to do this with a steel expander, not the boolit. Thing is, most rifle brass has about a .002-3" elastic limit depending on state of anneal, and the M dies have the "primary" step machined smaller than that. For example the .30 caliber one has a .307/.3105 mandrel and only expands a short part of the case to .3095 at the most after springback. If you're using a .310" boolit, it's having to stretch the .307" part out by forcing the gas check in there, and the brass is right at it's elastic limit. For some cases, it will be beyond the elastic limit, for others even in the same lot maybe not quite up to the elastic limit. Riding this ragged-edge makes for very inconsistent boolit tension, hence the reason I hate the steps. If you're going to make a stepped spud, which is a defective concept, at least make the step only about .0015" or so, so that the brass will be properly stretched and conditioned to function WITHIN its elastic limit when you seat the boolit.

The ideal expander spud for your particular gun and boolit size will work in conjunction with your sizing die. Size the neck down to where the ID is a couple thousandths below the diameter you want it before seating the boolit, then stretch the brass the other way with a good, parallel-sided expander that's the right size to give you about .0015" smaller than your sized boolit diameter after springback. The expander needs to be long enough to pass clear through the neck and expand the whole thing, and expand it straight in line with the rest of the case. It also needs to bell the mouth a bit so you can start the boolit, and this is an often overlooked thing with expanders: If the bell is part of the expander, it will open the mouth the same way all the way around. If you use a Lee Universal expander or one of the really short pistol PTE expanders, the flaring part isn't guided and centered in the neck by the expander mandrel and thus can stretch the mouth of the case more on one side than the other depending on the condition of the brass, which mind you is never as perfect as we'd like it to be. Having the bellmouth shank doing its thing while the expander spud is keeping it centered and piloted the full length of the neck is important. The M die does do this part, but in many calibers they don't bellmouth properly.

Now, "what about the parallel part starting the boolit straight?" you say? If the case neck is prepared to the correct dimension and tension, the boolit will go in there straight, because straight is the path of least resistance. If the boolit is having to stretch the brass past its elastic limit like is usually the case with M dies, it can push it any direction it wants because the resistance is the same, hence crooked cartridges with all sorts of runout and uneven cast neck tension on the boolit. The other thing I don't like about the M die is that after seating the boolit, you have lost fully a fourth of the holding surface of the case neck because you stretched it to the point it barely touches the boolit. If you think about it, that's sort of a dumb thing to do. If you use an RCBS or similar expander on your rifle case necks, they will grab the boolit with equal tension from the gas check to the base of the flare, and the flare takes much less length than the "starter" portion that the M die creates. I realize you don't necessarily have to push the second step very far down into the case, but the way they're designed, most of the time you have to to get the mouth open enough to start the boolit.

So there you go, it's all about proper neck tension, straight necks, and not deforming anything when you seat the boolit because the boolit is only springing the brass open a small amount and staying well within the elastic limit of the brass when seated. You obviously need to co-ordinate your sizing and expanding dies to work the brass a minimum amount, and often you must segregate your brass between rifles if you're really splitting hairs.

Many of you will argue with me on this and say "I've use and M die for 50 years and never had a problem". Well, fine. If you're happy with what you're doing, then it isn't a problem for you. But for some of us chasing accuracy and higher velocities, these things start to really show up, and the M die won't get you there most of the time.

Gear



I will add only one thing to Gear's great post. That is neck thickness. If the case neck is thicker on one side the thin side will expand more than the thick side and produce an off-center neck. The only way to correct this is to turn the case necks to a uniform thickness with a neck turning tool. After turning the case necks to a uniform thickness you may find that your sizing die will not size the necks enough to give the desired tension which will then require die's that utilize a sizing bushing such as the Redding bushing neck die

I fully realize that these steps are not required for hunting or practice ammo but for the person looking for one hole groups every little bit can help. Neck turning does not apply to straight wall cases as used in most handgun ammo.



Larry

[1hole]

"Gear has spoken very highly of RCBS's new "expanding" dies -- reckon I need to look into them. ---- Why bother? it can't possibly be an improvement over an (M) die could it? "

No, it can't be. But they can be, and are, copies of Lyman's "M" expanders, ditto Redding's copies of the same design. Redding and RCBS didn't do that without valid reasons.

[r1kk1]

Another company who makes all types of expanders for all die sizes.

http://www.ch4d.com/catalog/dies/expanding

I use tapered expanders for some case work for wildcats.

Take care,

r1kk1