As stated, send the question to CVA. There is a BP that can use #11 and Musket caps (with a nipple change) for the FireBolt/HunterBolt line of rifles, some guns came with both BP's. When you contact CVA, ask them about it. I recently asked about using the Optima style BP in my Bolt gun and they sent me one free of charge to try out to see if it had less fouling in the action. I recieved it 8 days after my first email to them so I thought it was pretty quick service. They sometimes do get backed up but so far I have always gotten quick responses from them.
Good luck and keep us posted.