#No

As I understand it, your goal is to make an explosive shell that survives firing and explodes after impact (or just before impact, in the very best case). That is not easy with metal shells and cannon, doing it with stone shells will be ever so much harder.

• You need predictable fuses. Firing a muzzle-loader is a lengthy affair. If your fuse train is, say, 2 to 20 seconds, you have a high probability that it will blow in the barrel. High enough that you won't get any experienced artillerymen because they die first.
• Non-solid shells will be quite likely to shatter.
• Even if the shell survives, the fuse will affect ballistics. It might be blown free from the shell, it might be bashed in, etc.

But building an explosive shell that will survive a catapult launch is probably feasible.

No

As I understand it, your goal is to make an explosive shell that survives firing and explodes after impact (or just before impact, in the very best case). That is not easy with metal shells and cannon, doing it with stone shells will be ever so much harder.

• You need predictable fuses. Firing a muzzle-loader is a lengthy affair. If your fuse train is, say, 2 to 20 seconds, you have a high probability that it will blow in the barrel. High enough that you won't get any experienced artillerymen because they die first.
• Non-solid shells will be quite likely to shatter.
• Even if the shell survives, the fuse will affect ballistics. It might be blown free from the shell, it might be bashed in, etc.

But building an explosive shell that will survive a catapult launch is probably feasible.