No experience with commercial pc'd bullets. I have been experimenting with my own cast/coated bullets.
Home cast/home coated/home made gas checks
A link to alloys and the pressures they are used for.
Cast bullet reference on lead alloy's, min / max pressure, lube, shrinkage,
There are 2 main coating being used right now:
Commercial ='s hi-tech/polyurathane
Home ='s dry powdercoat powder/polyester
Bullet size/design:
Anything under pressure will go to the least point of resistance. Add to that the fact that your asking a lead bullet to be under pressure, have the front 1/2 (nose) of the bullet start twisting in the riflings. While the back 1/2 is still being pushed/bumped up/enlarged in the ball throat of the chamber.
You want the size of the bullet to be the size of the ball throat. Too big and the bullet will get swaged down as it goes thru the ball throat being swaged to the size/dimension of the ball throat. As with anything under pressure, it will go to the least point of resistance. Too small and the same thing happens, side to side play movement and the bullet is bumped up to the ball throat's diameter.
You want a cast bullet that doesn't have a long pointy nose to it. When driven hard the nose will "slump" and accuracy will be destroyed. Bore riding nosed bullets can only be pushed so hard (pressure)/fast (rifling & twist). You will know real fast when you exceeded your bbl/bore riding nosed bullets stability/fit.
The lyman 311466 is a proven hv design.
lyman 311466 mold - Bing
A couple of guys got together and designed this bullet and neo makes the molds. They have gotten 3000+fps/2-moa with this bullet.
310-165-FN 30XCB, NOE Bullet Moulds
Myself I decided to use/test this lee bullet.
7.62 X 39 .312 Diameter 160 Grain 6 Cavity Mold CTL312-160-2R by Lee
As you can see all the bullets pictured above have a common theme. Namely, a short rounded/pointed nose (no nose slump) multiple shallow lube grooves, no wiper groove and they are not bore riding nose designs.
Wiper grooves are old/outdated. They were used back when lubes were well, iffy at best. Same goes for the large/deep lube grooves. Both of them are nothing more than a weak link in the body (chain) of the bullet.
I know you asked about 8mm bullets, I'm just putting out there what I've learned about cast/lead bullets when they are being used with high pressure/high velocity (jacketed bullet load data) loads.
If you don't use/choose a bullet with a strong body design that can take 40,000+psi and a nose design that can take 120,000+rpm. Then your just spitting in the wind.