R3m 25 breach Oring problem sealing

Ok, my stock breach Oring started leaking pretty quick (100 shots in or less) I didn’t have anything that would fit so I lived with it for a while. I got the closes I could and tried it but it didn’t seal. So, I got ahold of some 6×1.5mm orings and took everything apart and inspected everything. No issues with probe, breach bore, brass inset. Lubed up new Oring a title bit and put everything back together and I got hit in the face with a puff on the very first shot. I loaded another pellet, removed the mag, pushed the bolt back in and covered the probe /Oring area with grease so be sure that was was where the puff is coming from. I took a shot with my fave away form the spray and sure enough all the grease around the probe was blown away. So, anyone got any advice? Did I fail to alight something properly? I tightened down the breach bolts and receiver using a staged torque, criss cross pattern with the probe pushed all the way into the breach. I didn’t know if it had to be alighted or not, so I took every precaution. The Oring I used is a quality 70d automotive Oring that I think is a motorcycle drain plug or fuel injector Oring. Not sure, but its not some cheap harbor freight thing(not that those are bad either). I know a lot of people like to use higher durometer stuff, but that should only increase durability, not initial function.in fact, a softer matierial should actually seal better. It’s the resistance to wear and abrasivion that is makes the harder Orings popular, not a better seal potential. If ou don’t mind swapping them out more offten, an ever softer material would probably make things a little smoother.

P.s. if anyone has issues getting the brass inset out of the barrel, I found one of my old mechanic tricks works just great. Take a plastic tube or line or something that fits inside the insert snug to a little loose. Then find the right size Allen wrench that fits in the tube kind of tight and push it into the tube, then pull the whole thing out. I used a hollow eraser from a mechanical pencile I found laying right next to my work area. Fish tank line or thin vacuumed line may work well also. Mine would not come out(even with the sets crew removed.

P.s.s there is a hole in the receiver that lines up with the brass interest set screw. Looks like its there so you can remove the insert while the receiver is still in place. However, the valve body would be in the way. Anyone know what the purpos of this access passage is?

Thanks.