is this teaching true?
a man i used to talk to said that the once saved always saved teaching is baloney
The question is not can a true Christian walk away from Jesus. The real question is, can Jesus lose a true Christian?
The answer to this question depends on whether you think salvation is man centered or God centered. IF you view salvation as God's work for His own glory, and you believe that God always keeps his promises, then it will be impossible for you to conclude that Jesus can lose a Christian, because God promises to keep us until the end. The Bible says that God is working salvation in us, unto completion. Can God fail to do that? The answer is no. God cannot fail.
There are times when professing (key word) Christians fall away from the faith. But when this happens, it isn't that a true Christian fell from Christ, it's that he was never a true Christian to begin with, as John says:
1Jn 2:19 They went out from us, but they were not of us; for if they had been of us, they would have continued with us. But they went out, that it might become plain that they all are not of us.
This matches what Jesus in several places. One place is the parable of the sower. He said some people are "stony ground" or "bad soil" and when the seed is planted, it springs up temporarily, but eventually it withers away and dies. Also, Jesus taught that there are tares among the wheat
So there are people who claim to be Christians, that really aren't. They always fall away from the faith. But they aren't losing their salvation - they never had salvation to begin with.
The truly saved Christians will always believe in Christ until their death, and thus, will never lose their salvation.