Don't know if Jarvis does, but several manufacturers do.
To get back to the initial question asked on this thread, I had a .357 SIG pistol (a Glock 33) way back in the mid/late-'90s when they first came out. I shot about 2200 rounds ($ouch$) through it before trading it off a year or two later.
Here are some things that I noticed:
The .357 SIG (like all bottlenecked pistol rounds) feeds like a dream. You're shoving a 9mm pole into a 10mm hole - my gun
never had feeding issues.
The .357 SIG initially had problems with the bullets setting back into the neck of the case. The first cartridges did not have cannellures to hold the bullets where they should be, and I had to constantly eyeball rounds that I'd cycled through because they
did shorten - which could have been ugly given the edge-of-the-envelope pressures the cartridge operates at in the first place. I don't know whether this has been remedied (I see more mfgrs are cannelluring their rounds, but I don't know if it's solved the problem), but it
is a common problem with bottlenecked semiauto rounds - just look at the major crimp the Sovs put on the 7.62x25s. (I actually have a thread on Glock Talk asking about whether this has been fixed, because I've been thinking about getting into another .357 SIG pistol . . . .)
When I'd fire the microGlock in .357 SIG, people would always gather behind me to see what I was shooting. The concussion was like that of a .357 magnum full-bore round - it'd pound you on the chest. The actual
recoil of the gun was sharp, but not difficult to manage, even from such a small platform. I will say that it took me about 500 rounds to overcome the flinch I would soon develop as a result of the G33's concussion. My wife just flat-out refused to shoot it - it's not a novice's gun (but we're on the Rohrbaugh Forum, so it's fine for anyone here
).
The rounds aren't cheap. They've gotten better, but they're still not cheap. They're also not as easy to find as .38/.357/.44s.
The rounds were accurate, or at least just fine. My group sizes were the same from the G33 as they are from my G26.
Anyway, hope this was of interest and use.