Majbg,
I have the 30-30AI in a 24" custom shop barrel and really like it. The velocities that I get run as follows:
125-135g. bullets can easily be pushed 2,800-2,900 fps.
150g. bullets can easily be launched at 2,700-2,800 fps.
I haven't tried any heavier bullets, since I use it for deer. The best group fired to date is the Nosler 125g Ballistic Tip which crowded 3 shots into .75" at 200 yds.
I don't think any larger .308 cartridge is neccessary for most deer. Case stretching has been practically non-existant. I picked up Lee's 30-30AI dies and have been happy with those.
I am very satisfied with it!
Buffalgun