Ive got an older model 7 18.5in barrel not sure on the twist rate. Chambered in 223. Im wondering if anyone knows if this rifle will be able to stabilize a 70gr bullet.
You need to do more research but it looks like 1 in 12.
A 70 grain bullet might stabilize but I would not load more than 2 or 3 to test it out. A 1 in 14.5 twist will not stabilize much more than 60 grains so a 70 should be okay.