Warren Muzzleloading in Arkansas offers .380 balls without the sprue. They appear to be swaged, like Speer or Hornady, but I've heard that they're cast and the sprue magically removed with Blackpowder Fairy Dust.
Anyway, they're very good balls. I bought 1,000 of them (10 boxes)for less than $70 a couple of years ago. I've found them very accurate and of high quality.
Send Speer and Hornady an email requesting that they bring out .380 inch balls. I've done so for some time. Perhaps if enough of us make the request, it will be done.
Your Uberti generally has deeper rifling than the other makes. However, I just got a little surprise today: When it comes to the 1860 Colt, Uberti and Pietta have identical groove depths of .006.
This is according to the 2003 Dixie Gun Works catalogue. I'm at work and can't check the 2004 catalogue at home.
Now, that's odd, especially since the Ubertis elsewhere in the catalogue generally have groove depths of .011 inch.
Why Uberti would make the 1860 Colt with shallower rifling is anyone's guess.
My Colt 2nd generation 1851 Navy, whose frame, barrel assembly and cylinder were roughly produced by Uberti for Colt, has rather deep rifling. Not sure what it measures but it's obviously deeper than most. It's a good shooter too, probably partly for that reason.
Uberti makes very good revolvers. In the past two or three years, Pietta has raised its quality as well and is on the tail of Uberti.
The Colt Signature Series should be avoided. Quality problems there. The earlier Colt 2nd generation (1970s to mid 1980s) is extremely well made and finished.
I'm told that Cimmaron Arms orders Ubertis, but has them finished to a higher quality than regular Ubertis. Not sure about that, perhaps someone else can attest or dispute that claim.
Armi San Marcos is poorly made. Don't bother.
The revolvers sold by Pietta are generally Pietta, but of a lower quality than the Piettas I've seen sold under the Traditions label.
Conversely, I've known people to get very good Piettas through Cabela's.
You pays your money and you takes your chances.