change randomness to less shifting vars

src/Main.sol

@@ -236,10 +236,11 @@ contract Main is Owned {
     function sendBombs(uint256 _amount) external missionNotCompleted {
         // Ensure _amount will not exceed wallet balance of bombs, Unaboomer supply, and active Unaboomers
         uint256 supply = unaboomersRadicalized();
-        require(_amount <= bombBalance(msg.sender), "not enough bombs");
+        uint256 bal = bombBalance(msg.sender);
+        require(_amount <= bal, "not enough bombs");
         for (uint256 i; i < _amount; i++) {
             // Pick a pseudo-random Unaboomer token - imperfectly derives token IDs so that repeats are probable
-            uint256 randomBoomer = (uint256(keccak256(abi.encodePacked(i, block.timestamp, msg.sender))) % supply) + 1;
+            uint256 randomBoomer = (uint256(keccak256(abi.encodePacked(i, supply, bal, msg.sender))) % supply) + 1;
             // Capture owner
             address _owner = unaboomer.ownerOf(randomBoomer);
             // Check if it was already killed