Try just loading one round, and then removing the magazine. Use a bench rest. It's tedious, but it will answer the question of whether the issue is the weapon or the shooter far more quickly. Then have someone else shoot it and see if it's still happening.
If it's the weapon, the crown could be an issue. Easy fix. If not, the barrel may not have been installed correctly. Send it to Ghilliebear or someone similar to get that resolved. If it's you, take a class.