In looking at the web sight, the diameter is listed at .355. Doesn't this aspect bother anyone? I I was hoping to see .356 or choices.
Does it bother me? No. The standard diameter for 9mm jacketed rounds is .355. That's the way it is. Standard for lead is .356. That's the way it is.
It's much more important to get the size right with lead than with jacketed. When the rifling lands start engraving the bearing surface and start turning the bullet, there's a lot of lateral force being applied against the walls of the shallow grooves being carved into the bearing surface. Because lead is so soft, the lands need to bite deeply into the bearing surface to avoid deforming and smearing away that wall enough that the bullet can "jump" lands. The result of jumping lands is horrid accuracy, possibly tumbling.
A copper jacket, on the other hand, is not nearly as soft as lead, and the lands don't need to bite as deeply for the bullet and rifling to function properly.
So we have jacketed bullets standard at .355 and lead standard at .356.
That said, while those standard diameters usually ensure proper function, there still may be an accuracy advantage in shooting .001 or .002 over standard. This is easy with lead because many manufacturers of cast bullets offer sizing as an option when you order.
With jacketed, choice of over-sized bullets is extremely limited. In 9mm, the 115gr Hornady HAP is advertised at .355, but it's .356. Hornady advertises 125gr HAP at .356, which it is. Other examples include Precision Delta and Zero bullets, both of which sell .356 jacketed bullets, but with both companies, they're marketed as 38 Super bullets.
For Precision Delta, you have exactly one option the 124gr FMJ-RN. They're the same price whether you buy them for 9mm or 38 Super.
With Zero, their 9mm and 38 Super. they have 115gr as their light JHP for 9mm and 121gr for 38 Super. The 121gr JHP sized .356 is actually a hair cheaper than the .355 9mm, but close enough to call it the same price, and they also have a 125gr JHP in both 9mm and 38 Super, and they're identically priced.
So no need to pay a premium for .356 jacketed unless you want to buy HAPs.
How they shoot is a better indicator.
^^^^^ THIS ^^^^^
It's the ONLY indicator that matters.
If you've slugged your barrel, throw the record away. It doesn't matter. Let the gun tell you which it prefers. I was talking to your gun the other day, and your gun told me that your calipers are unreliable and possibly alcoholics.
For the record, MY CZ-75 Shadowline shoots the Precision Delta 38 Super .356 FMJ-RN into smaller groups than it shoots the Precision Delta 124gr JHP. It's the same with standard sized lead vs over-sized lead. Over-sized lead produces smaller groups. My HK VP9 is the opposite and shoots best with standard sized bullets. I did not determine this with either of the guns by hammer a piece of metal into the bore. I did it by loading and shooting.
That's my two and a half cents.