Before you buy anything, check the stem that comes with the set. Turn the stem hole up, set a bullet into it.
- If it squares up, doesn't wobble, stands up straight, use it.
- View attachment 351468
- If it hits the bullet point, drill it deeper or buy a deeper stem.
- If it doesn't hit the point but wobbles, buy a different stem, bed the stem, or lap the stem.
- http://bulletin.accurateshooter.com/2020/04/tech-tip-lapping-the-inside-of-seating-stems/
If your stem doesn't work with the VLDs (it probably won't to be honest) and you need to buy a new one - IMO skip the M or X and get the A-Tip stem for that caliber. It's deeper and should fit better even without lapping.
These seating stems are designed to fit Hornady® Custom Grade™ Dies and are machined to fit the profile of the A-MAX®, A-Tip®, ELD® Match, ELD-X®, FTX® and MonoFlex® bullets to seat them as precisely as possible without damaging bullets. (Not compatible with other manufacturers’ dies.)
www.hornady.com
I have a bunch of stems, .308 cal and maybe 6mm, plus some VLDs and A-Tips, if you want to see differences let me know and I'll try to take some pics tonight.
Pic source:
When loading a Very Low Drag (VLD) bullet or a hybrid bullet, we recommend that you use a VLD seating stem to ensure load consistency.
bergerbullets.com