Sent him an email.just get a 4" bag works well.
Why reinvent the wheel.
Alex Wheeler has 4" bags or ask edgewood or protekter to make one for you.
what thud said, a 4inch bag will work fine. he did make some wider tops but you dont need one for a 4" bag. its what I use on mine. when you get one you'll love it!!! great rest!! and dont forget to check the oil!!!! LOLDoes anyone have such? Know anyone who could build one?
Up front, I will say I don not own a JJ rest but interested. Just need to be able to get my four 4" BR stocks to work with the bag.