I think every seating die is designed wrong. Here's why.

[Hohn]

I've shared here and elsewhere my frustrations with my Forster seater die and the thin walls on the stem that inevitably lead to the stem flaring, which then leads to the stem OD scuffing the bore, then galling, and of course erratic seating depth.

The flaw in the Forster design is that they grab the bullet so low on the ogive that the stem walls are too thin.

The Redding seater grabs the bullet higher and in doing so allows a thicker stem wall. But it grabs the bullet higher-- and I think most of us would say this isn't desirable.

The design flaw they share with the popular Wilson hand die seater also. Namely that flaw is this: the use of a main bore that is precisely sized to near bullet diameter to "ensure straight seating." This forces the stem to either be too thin or grab the bullet too high.

But if you think about it, you'll realize why this is a flaw, and how wrong it is to believe that the center bore of the seater must be near bullet size. The bullet during seating has its position determined by the case neck and the stem. *EXCLUSIVELY*. It frankly doesn't matter if the clearance around the bullet between those two points is 0.0005" or if it's 0.5"-- the effect on seating concentricity is the same. Because that part of the bore isn't a functional part. It does NOTHING to ensure the bullet stays straight during seating. (and that's even if you hold to the idea that concentricity is determined by the die and not mostly by your brass-- an idea I think most of us now consider to be anachronistic.)

Indulging this myth that the bore contributes to straightness or concentricity isn't innocuous. It has a real cost in that the stem is needlessly fragile and very imprecise or it makes the bullet fit poorly.

And if you think about it-- shouldn't the stem grab the bullet using the same 1.5 degree throat taper your chamber probably has? A taper angle already used on many bullets to match that throat? (Sierra in particular).

Shouldn't a properly designed seating stem mimic the exact effect of soft seating a bullet in a chamber? Only do it in such a way that allows greater neck tension?

And that gives me an idea....

JH

 

[AckleymanII]

I have bored out seater stems, put a tad bit of bedding compound(after applying release agent on the bullet) in the seater stem, pushed in the bullet that I am using, perfect fit.

This leads to a seater stem for each type of bullet used, within reason.

 

[mikecr]

I agree with where you're going with this: to go with a thicker, larger diameter seating stem.
And that concentric seating would not be hurt by this action.

We do still need to contact the bullet low on bullet noses, to reduce wedging while seating under varying high forces. ~1.5deg will not work low on a nose,, it would cut a ring on mismatched angle.
Soft seating using a chamber throat does not work consistently, because ~1.5 is too low of a contact angle to press against with high force. It just wedges all over the place.

So an ideal stem would be strong enough to resist opening under forces, thicker, or harder steel to achieve it.
Bedding of the stem to specific bullet ogive also helps of course.

 

[Hohn]

I agree with where you're going with this: to go with a thicker, larger diameter seating stem.
And that concentric seating would not be hurt by this action.

We do still need to contact the bullet low on bullet noses, to reduce wedging while seating under varying high forces. ~1.5deg will not work low on a nose,, it would cut a ring on mismatched angle.
Soft seating using a chamber throat does not work consistently, because ~1.5 is too low of a contact angle to press against with high force. It just wedges all over the place.

So an ideal stem would be strong enough to resist opening under forces, thicker, or harder steel to achieve it.
Bedding of the stem to specific bullet ogive also helps of course.

I’ve floated the idea of using hard o-rings in deep cut glands in the ID of the stem. They would fully compress under seating force and *just* allow metal to metal contact.

This should allow a very low grab on the bullet without wedging, because the resilience of the o-ring should act a bit like an ejector for the bullet ogive.

This might allow a person to get away with “ring” contact on the bullet without damaging it, and thus make the stem essentially universal for ogive shape for a given caliber, preventing the need for bedding or for custom stems.

 

[mikecr]

The wedging issue in my context is about detriment to seating depth accuracy.
But it does also lead to a pulling at noses on press release.
There is always going to be some wedging on angled soft bullet jacket material, as stems currently function.

Your o-ring idea might develop into a great improvement, or fail in flames..
Go for it

 

[Dusty Stevens]

I say get a better quality die. Forster is not anywhere near top quality stuff

 

[drop_point]

I say get a better quality die. Forster is not anywhere near top quality stuff

What is your recommendation?

 

[Dusty Stevens]

What is your recommendation?

Whidden for off the shelf threaded die, wilsons work good for arbor presses

 

[acloco]

Whidden for off the shelf threaded die, wilsons work good for arbor presses

Bullet still has to fit the seating stem.

This became readily apparent when VLD styles of bullets entered the market.

 

[Clancy]

Bullet still has to fit the seating stem.

This became readily apparent when VLD styles of bullets entered the market.

Yes they do. Whidden has a lot of stems to choose from, or will even make a one off for you. Very, very good dies.

 

[mikecr]

Wilson seating stems and die fitment are as Hohn described. Are Whidden stems a different design from Wilson?

 

[Sniper338]

Wilson seating stems and die fitment are as Hohn described. Are Whidden stems a different design from Wilson?

Wilson makes different seating stems.

 

[NZ_Fclass]

Its all good thinking. I agree on the awful Forster stem - it took me a while to polish it to an angle that works for my bullets.
Perhaps replaceable seating rings, similar to sizing bushings could be designed with differing sizes/angles?

 

[Ledd Slinger]

I have bored out seater stems, put a tad bit of bedding compound(after applying release agent on the bullet) in the seater stem, pushed in the bullet that I am using, perfect fit.

This leads to a seater stem for each type of bullet used, within reason.

Same here. Did that with standard Redding seaters many years ago and it results in nearly perfect bullet bearing surface runout.

On another note, I don’t have any issues or reason to modify the ‘VLD’ stems in my Wilson seater dies. They work very well.

 

[209jones]

Thought popped into my head, that they may work better, if they were constructed more like a bushing die with a solid top on the bushing. Not sure how you'd overcome accumlative effect the upstroke impact to the plunger on the adjuster though if you left it loose off the plunger. Could still thread it to the bushing, die body might wind up a bit longer. Use an interchangeable head assy on a sizing die?

 

[Hohn]

Update:

I’ve added a few additional ideas to my concept of what an arbor seater should be.

1) it should use a counterbore that holds standard neck bushings to hold the neck in place. Go 0.001” larger than your common loaded round diameter. The bushing should be the tapered bore kind from Wilson or SAC, NOT a straight cylindrical bore like Redding or Hornady bushing (I believe).

2) the body of the case need not be fully supported in a seating due. Rather, it just needs a location ring right around the 0.200” line the reduce the potential for the case canting in the die. But it doesn’t need to be super tight— even 0.005” clearance would be plenty tight and reduce the risk of case sticking in the sizer as some folks report with Wilson dies.

 

[Hohn]

Wilson makes different seating stems.

To my knowledge they just have regular and vld stems like Redding.

 

[gunsandgunsmithing]

Just FYI here... A few years back, I tied a world record shooting a 220 Beggs, seating bullets with a 6ppc seating die. Think about that for just a second.

 

[Rat Rifle]

None of this makes any difference. In a 28” barrel, the bullet has 26” to get its sh*t together before it leaves the muzzle, or it never will.

JUST MY OPINION !!!

 

[Dusty Stevens]

None of this makes any difference. In a 28” barrel, the bullet has 26” to get its sh*t together before it leaves the muzzle, or it never will.

JUST MY OPINION !!!

So you dont think a bullet with severe runout makes a difference and it will just straighten itself out?