1+ on what Quick said.
When H&R/Rem repaired my 44mag, they inexplicably returned the barrel to me without the extractor. They said to send back and they would intall, or they could send extractor to me. I chose the latter to save time. I'm not very mechanical, and I was easily able to put it in, no problem. If you don't remember how the original came out, you can find schematics on the internet, I think maybe from H&R's website. That, and instructions in the FAQ's make installation very clear. Be aware that different extractor and ejector mechanisms have been used over the years, and you may have to get the schematics specific to your particular rifle.