Jim,
To tell you the truth I don't think you will find out at what velocity it will strip at. I've been shooting the 6.5 Swede, the 6.5 Grendel, the 6.5 Mannlicher Schoenaur, and my Colt HBAR and the twists on those are 7.8, 8.0, 8.0, and 7....I'm using 50/50 alloy that is WW/pure-lead both air cooled and water dropped and haven't stripped any at high velocity. So don't worry about that unless you start shooting pure lead which I don't think you will out of the Garand.
By the way 1900 fps is about the bracket I stay in with my 06's with various powders.