Originally Posted by Boxerglocker
You could safely start at about 4.0 to for testing purposes to make your requirements. I know several using Solo with 9mm 124 RN and depending on the bullet are all loading 4.2 or greater with OAL of 1.130 or greater (limited by driving band).
I'm one of the several running the 4.2gr 125gr LRN in a G19/26. Runs great. I've used this for IDPA as well.
3.8gr won't cycle my G26 consitently. 4.0gr seems to just barely. So, I just run the 4.2gr.
Just started to run some CCI SSP mag primers I got cheap, too. Dropped to 4.0gr, no issue. Then, 4.1gr. Both were fine.
I was running a 147gr LTC load that sucked. I think it really needed to be bumped to 3.8gr or more, but I used up my small stash before realizing that.
Solo 1000 is an excellent single-base powder. I like it. Keeps the gun very "cool" compared to Titegroup. Smoke can be hit-and-missed basd on bullet lube, but it seems better overall than double-base powders I've used with lead.