After measuring my Silhouette PCP I also got the same dimensions as Rezarf, however, the bolt holes for mounting the breech, and the length of the beach are exactly the same. So rather than buying an entire PRod, you could purchase just the breech and swap it out to have the ability to use both your single shot tray and magazines.
Casey
P.S. There's a reason we refer to most of the Crosman pistols especially as the Lego's of airguns because you can build anything you want from them. In this case, Crosman chose wisely to use the same dimensions for both their single-shot breech, as well as the PRod breech. Thus saving cost on their end and giving us the options when we look a bit closer to once again take a part from one and simply use it elsewhere.