I can’t think of any ammunition designed specifically for SMGs except for the Italian M38, and that was because the Italian military did not, at that time, use a 9x19mm pistol designed for the 9mm Parabellum cartridge, only the lower power 9mm Glisenti. Even then, the M38 ammunition seems to be well within the pressure range of the majority of 9mm Luger/Parabellum pistols. A LOT of 9M38 Italian ammunition from WWI and after has been sold as shooting ammunition in the US and I have never heard of a complaint.
The Winchester 9mm ammo bought by the British initially, was originally developed for the Finnish and was patterned after the Finnish made ammo from the late 1930s. The Finns provided Winchester with two Soumi M31 machine pistols and boxes of the current/recent production ammunition. This Finnish ammunition was loaded with a 115gr bullet which was initially designed specifically for the M31. In 1931, 9x19mm ball ammunition was, as far as I can tell, all modeled after the standard German ball load with a 124gr bullet. The Finn’s seem to have been the first to introduce the 115gr bullet in 9x19mm specifically for the MP application, to provide higher velocity for a flatter trajectory and longer range than provided by the 124gr bullet. The Finns were using this load by 1934. It is probable that the Finns developed their 115gr bullet from the 9mm Steyr bullet which was developed before WWI and was 115gr, the only 9mm 115gr bullet I know of from that time-frame.
The Finnish cartridge may have been another case where the cartridge was designed specifically for the M31 MP, the Finnish military pistol in 1931 was, I believe, the 7.65mm Luger. The Lahti pistol is designated the M35 so it was likely designed to handle the Finnish 9x19mm round designed for the M31. Like the M38 loads, very large quantities of Finnish 9mm from WWII have been sold in the US commercial market with no apparent problems.
The Italians adopted the 115gr bullet by 1938 for their M38 machine pistol. I can find no written record of how they settled on that bullet weight, but it is likely that, during the development of the M38 concept, they tested other 9mm machine pistols, and the Finnish M31 probably figured significantly in these tests.
Winchester records indicated that they produced 115gr, 9x19mm ammunition twice for special orders other than the Finnish order. The first time was in 1934, for an unnamed South American country, probably in conjunction with the Chaco War. The M31 is listed among the weapons used during that war. The second production of 115gr ammunition was for Mexico in 1939 as I remember.
The ammunition from the Finnish contract was never shipped. It was still in storage in the US when the British came looking desperately for 9mm ammunition and it was the first British WWII buy of Winchester 9mm ammunition. I have found no evidence in the Winchester records that the British initiated any changes to the basic Finnish design (except to use their standard chopped cordite powder in place of the Winchester powder). The first British design drawing of the 9x19mm cartridge was submitted to the Design department in June 1941 and appears to be basically the same as the Winchester round, but using a different powder. This makes sense since the design of the Sten began in the Fall of 1940 and production began in June 1941 so the Sten must have been developed using Winchester ammunition. Subsequent to the British adoption of the 115gr bullet, and post-WWII, the 9mm 115gr bullet became essentially the standard bullet for machine pistols worldwide.
I think that many, probably most of the military production of 9x19mm ammunition is intended for use in machine pistols, but it makes sense logistically to constrain the load so that it will function safely in military 9mm handguns, and that was a major consideration in the NATO STANAG that defined the 9mm NATO cartridge.
I’d have a hard time identifying any 9x19mm round specifically intended exclusively for use in machine pistols. Even the L7A1 rounds carry the NATO mark indicating they were intended for use in both modern military pistols and machine pistols. The fact that they are not appropriate some pistols, and likely in some “modern military” pistols is an error in it’s design, not because it was designed for use only in machine pistols, unless the NATO marking was applied incorrectly.
As has been stated by others early in this thread, there are quite a few rounds specifically designed for use in pistols and so identified, but I know of no 9x19mm standard military ball cartridges off the tip of my head appropriate only for use in machine pistols.
DK mentioned earlier there are quite a few specific loads designed for use only in specific machine pistols like the MP5 frangibles and there are also a number of subsonic loads. The most common “machine pistol only” load I know of is the Swedish training round with the black plastic bullet and the steel ball in the tip. The companion blank with the red plastic bullet also qualifies since I know of no applications where the muzzle cone used for these loads was issued with pistols. There are similar examples out there.
PS: Doc, I know the Mk1Z was considered weak, due to the use of chopped cordite power, but I have not heard that the Winchester 115gr rounds were considered weak. Lots of arguments between Winchester and the British inspectors on bullet pull tests and waterproofing and other issues, but no indication of low velocity. I understand the Winchester 9mm was the same velocity as the Finnish ammunition.