...hmm wasn't aware of that. Need to speak with someone in the group then. Maybe I was given misinformation then because SASS is listed among the books permitted in the current Missions FAQ.
The Missions rules on legality are as follows:
1. If the supplement will be pdf only, it becomes legal 30 days after release, unless it is entirely optional (Bullets & Bandages) or the Missions FAQ forbids it.
2. Some pdfs are mostly illegal (Assassin's Primer), since most of it is optional (Codes of Honor), with a few items that are legal (SVD sniper rifle).
3. Supplements that will have a pdf
and hardcopy become Missions legal 30 days from the announced street date of the physical book. Optional rules in those books are generally illegal, as well as anything Missions specifically doesn't all from that book (certain qualities, etc.).
Normally this wouldn't be an issue, but Personalized Grip is a special case. It was in a pdf only supplement near the start of 5th Edition, and was listed again in Hard Targets. Since it was already Missions legal from the pdf only supplement, it remains that way. Hopefully that makes more sense.