I suspect the Marines have realized even they have only so many supermen who can carry a CG and an M27. The little less weight of an M4 would be nice. And since M4 and M27 use the same mags, wouldn't  be too much of a problem using both weapons.

That seems logical.

And here is plan q

YouTube

Evolving the Cheek Pistol Concept: Calico M950

https://utreon.com/c/forgottenweapons/http://www.patreon.com/ForgottenWeaponshttp://www.floatplane.com/channel/ForgottenWeaponsCool Forgotten Weapons merch! ...

The SIG Rattler purchased by USSOCOM as ‘PDW system [which] will allow Operators to have maximum firepower in a concealable weapon.’

https://www.thefirearmblog.com/blog/2022/10/18/ussocom-sig-rattler-reduced-signature-assault-rifle/

I do not understand why both USSOCOM and the ADF are calling their MCX variants a "personal defense weapon".

It is clearly intended for use as a concealable offensive weapon.  Perhaps they just didn't like the "COW" acronym?  

YouTube

Sig Sauer MCX Rattler

Sign Sauer video

An article about  B&T USA's Universal Service Weapon chassis for the Glock small frame pistols (USW-G).  It is an aluminum chassis that provides a stock for Glock 17 and 19 pistols.  Although more bulky than the pistol itself, the folded system is reasonably compact and could be considered a "carry everywhere PDW".

The article is about it receiving a "national stock number".  

"The issuance of an NSN streamlines the product procurement process for all NATO members and partner countries, identifying all standardized material items of supply. The NSN number issued to the B&T USW-G is: 1005-12-420-1834."

https://www.thefirearmblog.com/blog/2022/10/21/bt-usa-usw-g-gets-national-stock-number-nsn/

Well, the stock number, if cited correctly, is a number assigned by the German (country code 12) logistics authority. Funny that nobody mentions this, in particular not the press release text.    

Somebody in the German logistics authority on the B&T payroll?  

In my opinion more likely the use of "navalized" Glocks by German special forces under the designation P9 (yes, a confusing designation considering the former use of HK P9 by police forces, among them GSG 9).

JPeelen said:

more likely the use of "navalized" Glocks by German special forces under the designation P9

Yes, that makes sense.  I did not know Glocks are used by any part of German armed forces.