I have been beating it on with a 3 lb rubber mallet for about 30 min a day for 4 days and it is on only up to the second pin hole (closest to the receiver). Now it feels like it is stuck and it not moving at all.

I first heated the gas block up to 400 degrees to try and expand it, this and a few whacks got it on about a third of the way. – just past the first pin hole. Since then it has been going a micron at a time.

One idea I had was using a piece of PVC pipe just larger than the barrel. Then I could pound straight down on that.