diff --git a/.gitignore b/.gitignore
index 01b9d96..f084773 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,7 @@ Testing/Temporary
 _codeql_build_dir
 _codeql_detected_source_root
 
+# CodeQL build artifacts
+_codeql_build_dir
+_codeql_detected_source_root
+
diff --git a/RingBuffer.hpp b/RingBuffer.hpp
index 3c92324..bcb4bdd 100644
--- a/RingBuffer.hpp
+++ b/RingBuffer.hpp
@@ -49,23 +49,27 @@ namespace buffers {
             ring_buffer_iterator& operator=(ring_buffer_iterator const& ) noexcept = default;
             template<bool Z = C, typename std::enable_if<(!Z), int>::type* = nullptr>
             [[nodiscard]] reference operator*() noexcept {
-                return (*source_)[index_ % N];
+                return (*source_)[index_];
             }
             template<bool Z = C, typename std::enable_if<(Z), int>::type* = nullptr>
             [[nodiscard]] const_reference operator*() const noexcept {
-                return (*source_)[index_ % N];
+                return (*source_)[index_];
             }
             template<bool Z = C, typename std::enable_if<(!Z), int>::type* = nullptr>
             [[nodiscard]] pointer operator->() noexcept {
-                return &((*source_)[index_ % N]);
+                return &((*source_)[index_]);
             }
             template<bool Z = C, typename std::enable_if<(Z), int>::type* = nullptr>
             [[nodiscard]] const_pointer operator->() const noexcept {
-                return &((*source_)[index_ % N]);
+                return &((*source_)[index_]);
             }
             self_type& operator++() noexcept {
-                ++index_;
                 ++count_;
+                if (count_ >= source_->size()) {
+                    index_ = N;  // Set to sentinel value (out of valid range [0, N-1]) when reaching end
+                } else {
+                    index_ = (index_ + 1) % N;
+                }
                 return *this;
             }
             self_type operator++(int) noexcept {
@@ -214,11 +218,11 @@ using std::bool_constant;
         // Iterator to oldest element.
         [[nodiscard]] iterator begin() noexcept { return iterator{this, tail_, 0};}
         // Iterator to one past newest element.
-        [[nodiscard]] iterator end() noexcept { return iterator{this, tail_ + size_, size_};}
+        [[nodiscard]] iterator end() noexcept { return iterator{this, N, size_};}
         // Const iterator to oldest element.
         [[nodiscard]] const_iterator cbegin() const noexcept { return const_iterator{this, tail_, 0};}
         // Const iterator to one past newest element.
-        [[nodiscard]] const_iterator cend() const noexcept { return const_iterator{this, tail_ + size_, size_};}
+        [[nodiscard]] const_iterator cend() const noexcept { return const_iterator{this, N, size_};}
         // Check if buffer has no elements.
         [[nodiscard]] bool empty() const noexcept { return size_ == 0; }
         // Check if buffer is at capacity.