Beeman P1 seal

I have 2 (one .22 HW45STL, one Beeman P1 .177) since 2006 never had that happen...

put a little grease on the face but I have never had a problem and it's just an O-ring, measure it up and buy a bag

they will nice an aged by the time you need one

i'll have to measure one to see what they are

I left a recent review on PA in which I think your quoting. I’ve had all variations of Beeman P1’s and HW 45’s back in the day with no issues. I decided to get back into one and read about there being an issue with the breech seal after a certain serial number but brushed it off. In July I purchased one new from PA and the seal kept popping out after every shot, frustrating to have to check and reseat the seal after every shot + it’s an expensive piece and I never had that issue with the older models I owned. After a few shots a chunk of the the breech seal came off and rendered the seal unusable. I installed the replacement seal and greased it with something the techs at PA recommend but the same thing happened with the replacement seal. I set up an exchange with PA and received a new replacement P1 about two weeks ago, guess what? Same problem... I’m on my third seal after 100 shots. This one seems to be holding since I greased the seal a bit more than before. 

The only way for the breech seal to fall out is if the barrel isn’t pushed tight against the breech when closed . If this is a problem loosen the two screws holding the bridge over the barrel and the grub screw at the front of the upper holding the barrel . Use a wooden dowel to push the barrel tight and tighten the grub screw . Open the action and retighten the two rear screws . 

Now if the barrel was machined with the notch too far forward , it would have to be machined to fix it . I’ve had three older model HW45 in each caliber , never had any issues with any of them . 

I really like my HW45 (AKA Beeman P1). I once bought a replacement breech seal after shooting some crossman 7.9's in it. They were very hard and would not seat all the way in. I though they were dragging across the seal so I stopped using them. The JSB 8.4's are so much better seating and accuracy wise.

Anyways, I didn't need to replace the seal, but it is just an oring. It looks like it would just pop into place and stay there since only a little bit of it is above the breech. Since the HW45/P1's piston goes backwards the recoil is rather unique. It kind of jumps forward. They are also quite accurate. Velocity is very consistent around 527 fps, so 30 or 40 yard tin can shots are very doable. I usually research and buy carefully and this is one airgun I won't be parting with.