The point at which the stock bracket mounts is about 1.368 inches in diameter which equates to about 34.75 mm. I have a custom machined bracket on my TX 200. I'll try to attach a couple of pictures.
You ordered a new one from Chambers? There must be a story how the old one broke. We'd love to hear it rather than speculate.
... have learned in the airgun game, if you have spares the originals will never break....
It is always good to have spare.1. Complete factory rebuild kit.2. Two sets of breech seals.3. Two front stock brackets w/stock screws.4. Two cocking shoes.The originals will never break, now..