stancrist said:

All I'm saying is that if the Army were to change its opinion on 9x19, there would be signs of dissatisfaction with the caliber well in advance of an announced decision to change.

Yes.
But this dissatisfaction could come once there is the comparision to something better. As you mention 9x19 is servicable. I agree on that. Especially if you want to use large numbers of handguns and not use an additional ammo type using 9x19 for handguns, SMGs and PDWs makes some sense. 9x19 is like .50 cal in this regard. It worked 100 years ago. It works now. Its the traditional, low risk, high inertia solution.
IF a SCHV PDW would be prooven to be superiour, which ironically can really only happen by fielding it in large numbers as standard issue preferable to be used in anger, there quickly could be dissatisfaction with 9x19 because there is something better around now. I think it would be the same with .50 cal. If something proven to be better would appear there quickly would be dissatisfaction and a move to replace it. Since this has not happened yet its the best thing proven to work.

Farmplinker said:

I suspect what holds back our 30SC service pistol is 1. "Hey, it's 9mm recoil and energy, so why change"? 2. "Who cares about pistol capacity"? 3. An attitude that any big improvement in military handguns isn't worth the effort.

In addition there is the lobbying of the established defense industry.
A lot of inovative equipment gets rejected or shot down during testing and evaluation because the large "go to" companies have no stakes in it and undermine such things.

Furthermore there often are legal troubles. Hasn't the APC9K been adopted because B&T has been one of the few companies who managed to fill out and deliver all the required documentation in time as well as having specs that are closest to the written down requirements?
If i recall correct on of the major problem holding things like the 6.5 Grendel back has been patent and IP rights. It was not "open source" so it has never been intresting for a large company to actually push this.

Then there is the administrative sind. A lot of the decision makers who have the last say are not experts. At least not for small arms, weapons or even things technical. They are lawyers and administrators. The proverbial bean counters. Of course these will make decisious that outright alienate engineers and soldiers.

schnuersi said:

...the transition from full length M16 rifle to M4 carbines as standard issue happend around 2005. The Marine corps switched even later. So at this point in time the official opinion obviously has been that even less effective range then that of the 20" M16 rifle is all that is required.

Requirements change.  At that point in time, what was required was a short, light weapon more suitable for CQB and use in vehicles.

Marine grunts react to switch from the M16 to the M4 (marinecorpstimes.com)

gatnerd said:

And the US had been aware of the 9mm and 13 shot 9mm Browning Highpower for decades before, but stuck with their 7 shot .45's, further supporting the argument that 30SC is a wayyyys off.

Indeed.  Although, in regard to the .45 to 9mm switch, by chance I came across this interesting historical tidbit:

"Army officials decided to switch from a .45-caliber sidearm to the 9mm in 1954..."  Infantry, Jan-Feb 2005, p. 5

And ISTR reading (a very long time ago) about the US Army testing the Colt Lightweight Commander in 9mm. 

--------------------------------------------------------

FYI:

YouTube

From the Vault: U.S. Army C.I.C. Colt 1911 Commander

Brownells Gun Tech™ Keith Ford shows us his early-production Colt Commander from 1951. In 1949, the U.S. Army issued requirements for a pistol to replace the...

schnuersi said:

If i recall correct on of the major problem holding things like the 6.5 Grendel back has been patent and IP rights. It was not "open source" so it has never been intresting for a large company to actually push this.

There are other, perhaps more critical, issues that held back 6.5 Grendel.  For example:

   - Excessive bolt breakage

   - Reduced magazine capacity

   - Inadequate magazine reliability

   - Lack of machine gun links

schnuersi said:

...this dissatisfaction could come once there is the comparision to something better.

IF a SCHV PDW would be prooven to be superiour, which ironically can really only happen by fielding it in large numbers as standard issue preferable to be used in anger, there quickly could be dissatisfaction with 9x19 because there is something better around now.

I think you're right.  The trouble is, it means that dissatisfaction cannot -- and will not -- occur because it depends upon first getting a SCHV PDW fielded in large numbers.  And that is not going to happen as long as everyone is satisfied with the 9x19 caliber.

6.5grendel is less of an issue for AK platform or any non ar15 platform and if county just happens to manufacture most of worlds 6.5grendel ammo..............

http://forums.delphiforums.com/autogun/messages/7504/1

stancrist said:

Requirements change. At that point in time, what was required was a short, light weapon more suitable for CQB and use in vehicles.

Exactly that is my point. Requirements change. They changed then, they changed after that and will change again at some point in the future.
This will happen to 9x19 as well at some point.

stancrist said:

There are other, perhaps more critical, issues that held back 6.5 Grendel.
For example:
- Excessive bolt breakage
- Reduced magazine capacity
- Inadequate magazine reliability
- Lack of machine gun links

All of these certainly could have been solved if there would have been an incentive to invest resources. But if someone holds a tight grip on patend rights nobody else is goint to do that.

stancrist said:

I think you're right. The trouble is, it means that dissatisfaction cannot -- and will not -- occur because it depends upon first getting a SCHV PDW fielded in large numbers. And that is not going to happen as long as everyone is satisfied with the 9x19 caliber.

Fully agree.
Unless someone does the first step the inertia will keep everybody at the "good enough" status quo.
This is not only true for the PDW topic but for quite a lot of pieces of military equipment.