D45 breech seal question

I’m almost embarrassed to ask this question but I’m going to anyway.
I am fortunate to own 2 D54’s , one in .177 and the other in 22. Both of them have been through the hands of Hector Medina so you know how well they shoot. Unfortunately I’ve had some breech seal issues with my .177 which is the earlier model. While looking to order back up breech seals for both Airkings,I’ve noticed that they come in different thicknesses but no mention the caliber? I’ve never taken the .22 apart but I have the .177 several times. The .177 and .22 can’t be the same diameter are they? Maybe they are ? I’ve looked at a parts diagram . It just says breech seal but no calibre?
I ordered and received from TW Chambers, a Vortek PG 4 tune kit for the .22. They included a breech which I didn’t order .It would fit the .177 but don’t see how it would fit .22? Just can’t seem to figure this out in my head.
Any help would be greatly appreciate it.
Thanks for taking time to reading my post,
Al