Whidden seating die; seating stem for Berger 105 grain Hybrid - jolt on release

[Dusty Stevens]

Looking at the Redding site - "Though the stem is heat treated to make it strong as possible it will not endure excess seating pressure of compressed charges". Why would Redding and other die makers heat treat seating stems? My guess is to prevent distortion and make them wear resistant. The advisory also uses the word, "hone" for die parts- this implies a grinding operation vs. a machine cutting type operation. Then consider making stems with a cylinder shaped recess for use with a soft epoxy liner - a cheap way to manufacture the item but it is not done. My guess is such an epoxy lined seating stem would quickly wear out or break. My original comment regarded the hardness of seating stems, they are not "plain ole SS". My experience has shown that applying a common, new, hardened steel twist drill to a heat treated seating stem will only make the drill dull and not make the seating stem deeper.

Possibly the die makers coat bullets with abrasives for some lapping operation to achieve a good ogive fit with the insides of a seating stem. Not seeing or discussing this procedure with Redding or others, my thoughts are that the lapping process be best done prior to heat treating the stem when the steel is softer then heat treating the stem. Should the dimensions of the ogive require removing even a small amount of material from a hard heat treated seating stem such a lapping operation would be an aggravation and take a long time. Attempting to perform this with "crocus cloth" would just unevenly polish the insides of the stem. Bullet ogives of the same bullet could be expected to vary somewhat, especially from lot to lot. The die makers probably compensate for that by only providing adequate stem depth and some well placed contact area between stem and bullet ogive to provide good straight bullet seating yet allow for minor changes in bullet ogives between bullet lots. I would not be surprised to hear that some manufacturing details are regarded as "proprietary" by the die makers and not open to discussion.

The OP said he could lift a cartridge by just using the seating stem. He also claimed that rounds "stuck" upon lowering the press ram. Rings were observed on seated bullets. The seating stem appeared to not be deep enough for the bullet. All this suggests a defective seating stem and it being likely this stem is heat treated like all the other seating stems I have seen, no amount of amateur drilling or lapping is going to fix it.

My suggestion to the OP remains unchanged - put the stem and a sample bullet in a padded envelope and send the both to Whidden. The OP probably paid $20 for some seating die stem that is inadequate for his intended use.

I would still like to see some actual hardness measurements for the Whidden seating stem as compared to the hardness of available twist drills.

Im just going by experience. I can assure you a whidden stem is non hardened SS. Doesnt matter what redding’s website says either, ive never had an issue with drilling their stems either. Seating dies are not usually hardened at all- sizing dies are a different story

 

[JMayo]

Seating force also matters. If it's too much then the copper jacket can't take it & deforms.
My vld slightly marks the bullet at the same point the op's pic shows.
On compacted loads it'll mark then more.

 

[SGK]

So I decided to contact Whidden. They suggested that it was likely that inadvertently I had been sent the seating stem for the Berger 105 VLD and not the Hybrid. They popped another stem in the post and told me to keep the one I had. It arrived today. While I have not seated any bullets with it yet, a Hybrid bullet extends much further into this stem than the other one and I can no longer lift a loaded round out of the box simply by pushing the stem onto it. Problem solved and excellent customer service from Whidden!!