I have tried using my hand reamers but it very difficult any body know an easier way of doing it??

You talking about the fighting butt split grip? I find the butt diameter, pick the closest-without-going-over Flexcoat pilot drill bit that I have to get the hold drilled half way, then follow up with the same size regular drill bit to finish the hole. I run the drill in reverse so it doesn't tear it up so bad.

Then, I chamfer the grip edge just a little, put a very small amount of rubber cement on the very end of the blank, then epoxy the rest of the way where the grip will go. Slip it on, clean it up, done.

That's what I did in the past. Now that I have a lathe, I will be using my lathe to center drill the butt. I've had issues with holes that weren't drilled straight even though I used the pilot bit first.

Jack, most people, myself included use regular drill bits (sharp ones) , increasing the size of the bit as you go to keep the hole centered till it can be installed . the winn grips can stretch a bit so aim for the smallest diameter of the section of the blank you are installing it on , that way you wont need to shim anything.
Good luck,
Tim

Ultimate Reamer. It will chew thru it no problem...and you hand too if you get it in the way.

put the reamer in a drill....no problem reaming

The best method for me was doing as Tim stated above using a set of drill bits. I mark the depth on the bit to make sure I don’t drill through. Find a bit that fits snuggly, turn until you reach the bottom, use the next size bit and repeat until you get the size hole you need. It only takes a few minutes and you get a perfectly centered hole. Fool proof.
Norm

Thanks all
I wound up doing different size drill bits to bring it up to size evenly and centered.
luckily I am a machinist and have access to sharp drills.