I received my new YHM 2 piece handguard today, thank you BrightFlashlights, and I am trying to install it on my M4 upper.  I have removed other handguards before, I do have the tool that holds the delta ring back, but I cannot get these to budge.  Are the M4 sytle any different from normal A2s?  Is there anything other I need to do then have the delta ring back and pull the guards back out of the front ring?  

Thanks for the help.  

Sounds like you are on track.

Make sure you pull the back end up first.

Also, try sqeezing the handguards in the middle real hard incase the two halves are somewhat stuck together.

Some times they are just a beast to get on an off.  I was checking out one of mine the other night and had to fight to get my handguard off, now I get the thing back on!

It certainly doesn't give me bragging rights, but it lets you know you aren't alone!!