Let's make a better expanding die

[Ian]

I've had it with crooked rifle case necks. It seems the one process for loading cast bullets that has no straight-line die option is expanding case necks, and I'd like to fix that.

Using bushing neck sizing dies or modified full-length dies minimizes the over-sizing typical of standard rifle dies intended for jacketed bullet use, but still I prefer to expand up at least a thousandth or two before seating because tests have proven to me it gives more uniform neck tension compared to simply turning the necks uniform and relying on the neck bushing to final-size the inside diameter to achieve the correct neck tension. Time for a better mousetrap.

What I had in mind is to use off-the-shelf, standard, inexpensive die bodies and make a sliding-sleeve insert similar to Forster's in-line seating dies, except instead of a bullet seating punch, have an expanding spud that aligns inside the sleeve at the top and has the necessary shape to do the job and put a minimal flare on the case mouth.

A Forster seating die itself would be a great place to start, but expensive. The sliding sleeve could be bored out slightly at the top for a larger-diameter spud than the seating stem, in order to make room for the slight bellmouth. The neck would be essentially un-supported, but the spud would be held snugly on-center by the sliding sleeve and thus the neck forced to be in the center of the case body.

The other option that springs to mind is the Lee Rifle Charging die, which costs $10-12 and has a step at the bottom that would keep the sleeve from falling out. A sliding sleeve, reamed with a chamber reamer, then bored at the top to slide over a precisely-fitted expanding plug, plus a spring, would be all that's necessary to add to the die. The aluminum cap could even be used to adjust the expansion depth.

I know, make one and show us Well, I thought I'd better check with the hive mind to see if there are any better ideas first. The biggest problem for me is boring a straight hole through a 2" steel rod and turning the OD exactly concentric. I guess I could just drill it through and then turn between centers with a faceplate and dog, just do half and swap ends. Ideas?

 

[Brad]

Could we make a sleeve like the Wilson case holders for their trimmers?
Let that hold the case firmly on center while pushing onto the spud. No need for the neck to be in the sleeve at all.

 

[freebullet]

Been using the Lee uni expanding die, with the noe plugs brad come up with, seems to work well.

I prefer expanding dies that don't give so much bell. In 45acp & 380 for example I run a Lee size die instead of the hornady because they open right without so much edge roll or belling.

Will be interesting..

 

[Ian]

Could we make a sleeve like the Wilson case holders for their trimmers?
Let that hold the case firmly on center while pushing onto the spud. No need for the neck to be in the sleeve at all.

That would sure help if we make it small enough to fit inside a 7/8x14 die body. Also, if the sliding sleeve doesn't pilot on some part of the expanding spud shank, alignment will depend entirely on the fit of the sliding sleeve in the die body and the spud being held on center from the top of the die. Do you think it would be better to have the spud and sleeve guide on each other, or am I over-engineering the concept?

 

[fiver]

something like this.

 

[Rcmaveric]

Just modify a Lee bullet seating die. Could you removed the bullet seating stem and then bore to accept an NOE expander? It would support and center the case on the up struck and then expand. It may take some fiddling to set the die up, but then it would be set for ever.

Most often when i crush a neck is because the case mouth nicks the expander.

 

[Ian]

Pretty much, Fiver, I should have figured you'd pull P/W on us! I think that's exactly the principle Brad had in mind. Might be easier to mod one of those for an expander (make just ONE part instead of two difficult ones) instead of my idea.

@Rcmaveric , the problem is precision. Lee stuff would work but only if sliding, precision-mating guts are used. Due to the taper of rifle cases, the case cannot be held perfectly in line with the expanding stem at the beginning of expansion. Only at the end of the expanding stroke can things come together, and only if you have the inside of the die bored to chamber shape, which the Lee seating dies sorta kinda are, ish. If the chamber-shaped support sleeve is made to slide inside the die body, it can fit the case closely (as in cut with a chamber reamer) for the whole trip and bring it in-line with the expanding spud, particularly if the body of the spud also slides down inside the sleeve from the top like a piston.

 

[Rcmaveric]

A spring behind the spud would make it self centering. The pressure would align everything with out damaging the case with the spud. Makes me want to go put spring in my universal sizer. I have never had a crooked neck though, only a crushed edges.

Using a neck sizer bushing would limit expansion. Not a bad idea then you could choose a size that matches the chamber (IE a .280 for my .270 Win) and don't have to worry about over belling. Case neck thickness would be important. I just tried it and neck sizer bushing fits inside the bullet seating die. You would just need to bore it open to allow the neck to slide through. The bushing would slide with no sleeve needed. Neck sizer bushing fall right through the Lee Universal expander.

Could also be universal aslong as the case diameter matched. Just change out the bushing and expander plug and do the next caliber.

 

[freebullet]

Starting with the le'cheapo uni die....
Expanding on the expander idea (Brad like pun intended)...

Turn the inside down a bit further(blue line), & make a sliding alignment sleeve (red part)...



Could use another bushing between expander & alignment bushing for proper spacing...or maybe a second spring between them .

 

[freebullet]

Problem being the spacing could jam it all together...

If the alignment plug held the datum point(like the bushings in a wft trimmer) on the shoulder instead of the neck itself, it wouldn't jam up & the neck opening size could be large enough to not jam.

 

[M3845708Bama]

something like this.

Look at the old headers. Or C&H seating dies. The seating stem could be replaced with expander and if sliding plug had a carbide sizing ring added would be similar to what you are looking for. I use the dies modified to align bore rider bullets which only require the case mouth to be champ

 

[M3845708Bama]

Champhered. Case is not flared as long as neck tension is maintained around 2 thousands. It also takes almost all the run out out. Just have to match case shoulder angle. Some of the old school guys were a lot smarter than they were given credit for. That is reason we must look at history of craft.

 

[Ian]

The old Lee "whack-a-mole" loaders were pretty good at seating bullets straight, too. Not as good as the benchrest hand-seating dies, but close.

One of the problems I have with runout is the case head moving around in the shell holder. I like to use Lee turret presses and they are not the best at keeping anything square or in-line. The Forster seating dies eliminate mis-alignment of the case at the bottom, and I want to achieve the same effect with the expanding die. Just supporting the shoulder on center won't keep the cartridge 100% straight with the expanding spud, and I can't see any purpose to a neck bushing doing the job because it has to have room for neck expansion. The neck itself doesn't need outside support if the case body is held straight, and exactly on-center, with the expanding spud.

 

[fiver]

I was kind of thinking that if AL's bushings could be used in the die body a stem is all you'd have to make.
further making the project easier.
you can't neck size down and expand up at the same time, physics won't allow that.
but if you held the shoulder from rocking and went over a longer tapered expander you could take a lot of the wobble out for sure.

the best way to do this might be to press the case in a solid rest and then come down with the expander into the neck.
for that you'd want the die to screw down on a C shaped piece with a mandrel that come down a tunnel kind of like a bullet puller collet only with a longer handle.

 

[Barn]

Same principal as my never disclosed gas check seating die.

 

[VZerone]

Just take the Forster seater die and drill out the bullet guide hole larger down into the shoulder just enough so that the slightly flared case mouth can pass through without collapsing it again. Change the bullet seater plug to an expander plug remember the size of the hole you openned the bullet guide hole to so they both work together. This brings up the one thing the Forster seater dies doesn't have and thats a crimping ability. If you need a crimp you're forced to buy a profile or taper crimper. Now I can't state that positively as I've never owned, for example, a Forster 30-30 seating die. Back to my idea you are stuck to buying a caliber dedicated inner sleeve for each of your expanders.

The slop in the shell holder is non critical especially when sizing as the sizer die has control of the case and the slop in the shellholder gives it wiggle room to prevent binding.

You guys shooting benchrest match competition with cast bullets or what needing such a precision expander die? Just saying.

On the mention of someone being tired of bushing sizer dies that are matched to leaving the inside of the neck to the corrrect diameter for cast bullet seating, but having to turn that necks....that's simply not true you have to turn the necks unless you're running neck clearances in the tenths of thousandths. This is providing your bushing die has the correct size expander plug preferrably a tapered carbide one.

I occassionally spin my loaded cartridges in my lathe and I load some pretty straight stuff.

BTW those old LEE pound loader are among some of the most accurate longers out there for the price. They load better ammo then you can achieve on a RCBS Rockchucker with the run of the mill RCBS reloading dies.

 

[Ian]

Just take the Forster seater die and drill out the bullet guide hole larger down into the shoulder just enough so that the slightly flared case mouth can pass through without collapsing it again. Change the bullet seater plug to an expander plug remember the size of the hole you openned the bullet guide hole to so they both work together.

Well, yeah, that would sure work. Problem is if you're like me and don't like changing a whole bunch of parts around for each operation, we would need to buy a whole die for each operation. I'd rather buy a $10 die than a $55 die and have to make parts anyway, especially if I already have the chamber reamer the rifle was chambered with sitting in a drawer.... Forster will ream custom sleeves if you provide the reamer, or sell extra sleeves for modification if you feel like swapping die parts and re-adjusting it for every loading operation.

Buying and modifying a Forster seating die would probably be the cheapest option if you don't already have a chamber reamer or the skills to single-point an accurate chamber shape with a boring bar. I've matched barrel tapers very closely before by setting the compound (tramming with a dial indicator to verify dimensions rather than fiddling with degrees) so boring a chamber sleeve is doable.

 

[VZerone]

ell, yeah, that would sure work. Problem is if you're like me and don't like changing a whole bunch of parts around for each operation, we would need to buy a whole die for each operation. I'd rather buy a $10 die than a $55 die and have to make parts anyway, especially if I already have the chamber reamer the rifle was chambered with sitting in a drawer.... Forster will ream custom sleeves if you provide the reamer, or sell extra sleeves for modification if you feel like swapping die parts and re-adjusting it for every loading operation.

No you don't have to buy the whole die as you know you can buy the insert sleeve. Of course they have a couple lengths. You wouldn't expect a 222 sleeve to work with the longer 30-06 body.

I see what I mentioned as the easiest solution. Now if you were a gunsmith that had lots of chamber reamers you could make the sleeves yourself. As you mentioned you have the one reamer so you're set to go with that caliber providing you have a Forster body.

 

[VZerone]

Here's another option Ian, buy a Lee sizer die for the caliber you want and use that as a basis for making a sleeve. You would then size your case the way that you use for sizing, then put it in the modified LEE sizer die as mentioned and expand your neck. Can't get any tighter then that. Sorry about making the gears (puns intended) turn inside your head buddy!

 

[Ian]

You missed my point about wanting multiple dies. I use turret heads and a dedicated die at each station, so yes I would have to buy an additional complete die for each caliber. Same thing with progressive press tool heads. If you batch-load on a single-stage press, buying the internals from Forster to modify and swap back and forth within the same die body makes sense.

The Lee sizing dies are hard as coffin nails and are wholly unsuitable for machining on a hobby lathe, so I'd have to say that might be impractical, but still a good idea.

You did give me an idea, though.....rather than having to have a chamber reamer for each die....just wax a sized case and mould a rough-bored steel insert with JB Weld. This would allow a fire-formed, neck-only sized case to be used for exact fit, or a FL sized case that's loose in a chamber.

Here's what I had in mind:



See how the expanding spud and sliding case sleeve fit together? That interface would be close-tolerance to eliminate wiggle or lateral movement and force the neck to be in the center of the body. Making an arrangement where the sliding sleeve doesn't interface with the expander, but fits closely in the die body and has the plug securely held in the center of the die by large-diameter, close-fit threads, would also work but I think require more precision to make.