Rod,
I originally sighted it in with CCI. Last week was shooting from the same batch. Was also shooting Remington. Both boxes are more than a few years old and both brands were showing the cracking problem.
I will deffinitly contact the company's.

Just had a side thought. I have been shooting 45-70 using the same frame. I'm hoping that hasn't compromised the frame itself as far as how other barrels lock up. When I close the .17 barrel everything seems to be tight.

Thanks,
Jeff