Roger,
I am not a Cowboy action shooter, but the shooting of the steel targets with the rifles occurs at very close range, approximately 20 yards. Because of this, high powered rifles cannot be used, and I believe the calibers are limited to 44 mag, .357 mag, 45 long colt, 44-40, and other pistol type rounds. (Perhaps the real old rounds like the 32-30 would be OK too.)
Also, the ammunition used must be a special, low powered, solid lead bullet round, so that when they hit the steel target, they splatter.
Obviously, the 30-30 is way way too powerful. I once shot a heavy metal T post at 50 yards with a remington core lockt 170 grain softpoint, off of my back porch, and to my shock, the bullet cut a perfectly
clean hole through the T post.
You have a really nice rifle.
Big Paulie