I have a 1/7 twist on my carbine. I have a mid length gas system...in case you care. I shoot 55 grain bullets all the time. They run great. No problem with spinning to fast. However when I run a 77 grain bullet through that gun I can shoot a three shot group at 100 yards with all the holes touching each other. That is less than 1/2 MOA. If you want to shoot heavy bullets for accuracy...you have the right barrel.
Some people even load heavier bullets than that. They load them so long that they must be fed one at a time because they wont fit in the mag. I haven't taken it to that extreme...yet.
Romans 1:16 I am not ashamed of the gospel, because it is the power of God for the salvation of everyone who believes: first for the Jew, then for the Gentile.