BSA R10 O-ring question.

[69TransAm]

Good afternoon all, A family member has my old BSA R10 in .22 caliber and upon firing the bolt is being thrown open slightly. It appears to be back pressure doing this. There is an O-ring on the pellet probe that looks a little "choppy". This O-ring is clearly visible with the magazine removed and the bolt in the forward position right about where the center of the magazine would sit, as you close the bolt this O-ring then goes into and through the magazine. Can someone tell me what size this O-ring is and a source to get a couple. He really likes the gun and I want to keep his enthusiasm up with it being reliable. Thank You

Tim

 

[Rodeo]

.22 bolt probe O-ring is BSA part # 16-6560.
3mm id x 1.5mm cross section.
For convenience, you can purchase that size o-ring from Amazon but they may not be made from as durable material as original.

 

[Rodeo]

I'm on a 6 hour ride to Rhode Island....
Got a bit of time so I looked it up.

Viton or Buna-N seem to be the better materials. I read that Buna has slightly better abrasion resistance.
The replacements that I got for my R-10 came in a rebuild kit from UK.

 

[69TransAm]

Thank you very much for the information. I will try to source them locally. Much appreciated Rodeo.

Tim

 

[davecole]

This link is EXTREMELY helpful reinstalling the Oring. Speaking from experience here.
Minute twenty-five is the start time for reinstallation.

 

[69TransAm]

Thank You for sharing this video Dave, very informative. I will apply the techniques shown.

Tim