Norm,
Thanks for the info on the 16# spring! I didn't address projectile weight in the information below, because the post was for the Mak forum where projectile weight isn't as critical as on a P64. Here are my measurements in a post I did elsewhere, but it's relevant here. I used my new Nesko caliper, which is just ok.
The AIM add has the actual boxes of the new Silver Bear pictured. I looked at the box and it says zinc coated. This leads me to believe it is RAM, but I'll get my ammo on Monday. My last box of old Silver Bear HP says nickel plated on it. My 9 month old boxes of RAM FMJ say zinc coated.
I was curious why some ammo feeds and some doesn't. Here is what I came up with so far. I took the extractor gap measurements differently because the actual gap is what is critical, I think. That seems to be the biggest factor.
Next is projectile shape and HP hole diameter if present. I didn't measure some parameters like weights, etc which obviously will affect things too. Mostly, I used just a single box of ammo and put the numbers to the nearest 0.1mm because there is so much variation cartridge to cartridge anyhow.
The cartridges I measured would all have a taper, but the projectile insertion bulges the casing. Only S&B and Wolf have a taper even with the projectile bulge. I think the center of the casing diameter is negligible because the projectile end of the casing is most critical for feeding. The web and projectile end together affect seating, I think.
Reeds ammo gave me slight casing bulges at one point on my CZ82. The reason appears to be because the casing is smaller and will expand more. Build up in the chamber for that range visit probably had an impact on bulging too. They use high quality starline brass as far as I know. Reeds didn't feed very well either. The chamber on my CZ82 is slightly larger than my Mak and P64.
RAM HP:
OAL=23.9mm
Casing length=18mm
Diameter at casing mouth=9.9mm
Diameter at extractor gap=9.9mm
HP hole diameter edge to sharp edge, exterior=7mm
Extractor Gap with Taper=2.4mm
Casing Taper web to mouth=No
Reeds Gold Dot:
OAL=23.9mm
Casing length=17.9mm
Diameter at casing mouth=9.8mm
Diameter at extractor gap=9.8mm
HP hole diameter edge to sharp edge, exterior=6.4mm
Extractor Gap with Taper=2.0mm
Casing Taper web to mouth=No
Silver Bear Old, 120g:
OAL=24.5mm
Casing length=18mm
Diameter at casing mouth=9.9mm
Diameter at extractor gap=9.9mm
HP hole diameter edge to sharp edge, exterior=6.4mm
Extractor Gap with Taper=2.4mm
Casing Taper web to mouth=No
S&B:
OAL=24.8mm
Casing length=18mm
Diameter at casing mouth=9.8mm
Diameter at extractor gap=9.9mm
Extractor Gap with Taper=2.5mm
Casing Taper web to mouth=Yes
RAM FMJ:
OAL=24.8mm
Casing length=18mm
Diameter at casing mouth=9.9mm
Diameter at extractor gap=9.9mm
Extractor Gap with Taper=2.4mm
Casing Taper web to mouth=No
MESKO FMJ:
OAL=24.9mm
Casing length=18mm
Diameter at casing mouth=9.9mm
Diameter at extractor gap=9.9mm
Extractor Gap with Taper=2.4mm
Casing Taper web to mouth=No
Wolf 100g FMJ cones:
OAL=24.8mm
Casing length=18mm
Diameter at casing mouth=9.80mm
Diameter at extractor gap=9.85mm
Extractor Gap with Taper=2.4mm
Casing Taper web to mouth=Yes
S&B feeds best on all of my 9x18's. The Wolf projectile shape is the biggest factor for feeding that ammo in my opinion. The portion of the Wolf projectile that extends out of the mouth of the shell, then drops off sharply as it starts to form the cone is probably the feature that affects some pistols differently.
I focused my comments and measurements on ammo that works well for me or doesn't work very well at all.
I got this picture with specifications, but I can't even remember where.