Triple 7 should be an easy powder to ignite. So, there are 3 main areas to look at:
1) Powder: Is it fresh or old, could it have absorbed moisture?
2) primers: If the musket caps are going off, they should have enough power to ignite 777.
3) Breechplug OR new gun.
I would doubt it is the size of the hole in the breechplug. Yes it is very small, but that is by design. However, they usually ship new guns with some residual oil in the barrel? Did you clean the gun thoroughly and pop off some caps before loading up for the first time. If not, I would break it down and clean the entire rifle and plug and give it another go.
Also, are you swabbing between each shot? 777 is a dirty powder and I run a spit patch (both sides) followed by 1-2 dry patches between each shot.
I have never shot a CVA, and don't really know their breechplug set up, so maybe someone who has will chime in. It is probably an easy fix. But I would not start out by trying to drill a bigger flash hole. That is the last thing I would try if nothing else works.
txhunter58
venor, ergo sum (I hunt, therefore I am)