Problem replacing the bolt probe o-ring on my Air Wolf

Is there a trick to get the o-ring on without it breaking? They have to stretch a lot to get over the step. The orings are the same size as the one that came off ( massive air blow by on the old one ) and I had a hard time getting it off and it ripped coming off.

How do you get the bolt out of the receiver? Having the bolt out would make it easier.
 
Apply a thin coating of silicone oil to the shoulder of the probe and a little on the o-ring. And then, patience, patience, patience. 

My brother grew weary of struggling with it, even with the silicone oil applied, so he drilled a small hole in a thin piece of hard wood, just large enough to fit over the probe. He then would use the hard wood to squarely force the o-ring on.

I'll keep that in mind. Thanks