diff --git a/lib/include/srslte/adt/move_callback.h b/lib/include/srslte/adt/move_callback.h
index f7335af83..a1b2f920c 100644
--- a/lib/include/srslte/adt/move_callback.h
+++ b/lib/include/srslte/adt/move_callback.h
@@ -172,7 +172,7 @@ public:
 
   R operator()(Args&&... args) const noexcept { return oper_ptr->call(&buffer, std::forward<Args>(args)...); }
 
-  bool is_empty() const { return oper_ptr == empty_table; }
+  bool is_empty() const { return oper_ptr == &empty_table; }
   bool is_in_small_buffer() const { return oper_ptr->is_in_small_buffer(); }
 
 private:
diff --git a/lib/include/srslte/common/timers.h b/lib/include/srslte/common/timers.h
index 4daf016fb..883604a37 100644
--- a/lib/include/srslte/common/timers.h
+++ b/lib/include/srslte/common/timers.h
@@ -20,6 +20,7 @@
 #ifndef SRSLTE_TIMERS_H
 #define SRSLTE_TIMERS_H
 
+#include "srslte/adt/move_callback.h"
 #include "srslte/phy/utils/debug.h"
 #include <algorithm>
 #include <functional>
@@ -45,11 +46,11 @@ class timer_handler
   constexpr static uint32_t MAX_TIMER_VALUE    = std::numeric_limits<uint32_t>::max() / 2;
 
   struct timer_impl {
-    timer_handler*                parent;
-    uint32_t                      duration = 0, timeout = 0;
-    bool                          running = false;
-    bool                          active  = false;
-    std::function<void(uint32_t)> callback;
+    timer_handler*                        parent;
+    uint32_t                              duration = 0, timeout = 0;
+    bool                                  running = false;
+    bool                                  active  = false;
+    srslte::move_callback<void(uint32_t)> callback;
 
     explicit timer_impl(timer_handler* parent_) : parent(parent_) {}
 
@@ -79,7 +80,7 @@ class timer_handler
       return true;
     }
 
-    bool set(uint32_t duration_, std::function<void(int)> callback_)
+    bool set(uint32_t duration_, srslte::move_callback<void(uint32_t)> callback_)
     {
       if (set(duration_)) {
         callback = std::move(callback_);
@@ -113,7 +114,7 @@ class timer_handler
       stop();
       duration = 0;
       active   = false;
-      callback = std::function<void(uint32_t)>();
+      callback = srslte::move_callback<void(uint32_t)>();
       // leave run_id unchanged. Since the timeout was changed, we shall not get spurious triggering
     }
 
@@ -121,7 +122,7 @@ class timer_handler
     {
       if (is_running()) {
         running = false;
-        if (callback) {
+        if (not callback.is_empty()) {
           callback(id());
         }
       }
@@ -164,7 +165,10 @@ public:
 
     bool is_valid() const { return parent != nullptr; }
 
-    void set(uint32_t duration_, const std::function<void(int)>& callback_) { impl()->set(duration_, callback_); }
+    void set(uint32_t duration_, move_callback<void(uint32_t)> callback_)
+    {
+      impl()->set(duration_, std::move(callback_));
+    }
 
     void set(uint32_t duration_) { impl()->set(duration_); }
 
@@ -270,8 +274,8 @@ public:
   template <typename F>
   void defer_callback(uint32_t duration, const F& func)
   {
-    uint32_t                      id = alloc_timer();
-    std::function<void(uint32_t)> c  = [func, this, id](uint32_t tid) {
+    uint32_t                              id = alloc_timer();
+    srslte::move_callback<void(uint32_t)> c  = [func, this, id](uint32_t tid) {
       func();
       // auto-deletes timer
       timer_list[id].clear();
diff --git a/lib/include/srslte/upper/pdcp_entity_lte.h b/lib/include/srslte/upper/pdcp_entity_lte.h
index bf982b7d6..13a017430 100644
--- a/lib/include/srslte/upper/pdcp_entity_lte.h
+++ b/lib/include/srslte/upper/pdcp_entity_lte.h
@@ -48,10 +48,10 @@ public:
   // Getter for the number of discard timers. Used for debugging.
   size_t nof_discard_timers() const;
 
-  bool add_sdu(uint32_t                             sn,
-               const srslte::unique_byte_buffer_t&  sdu,
-               uint32_t                             discard_timeout,
-               const std::function<void(uint32_t)>& callback);
+  bool add_sdu(uint32_t                              sn,
+               const srslte::unique_byte_buffer_t&   sdu,
+               uint32_t                              discard_timeout,
+               srslte::move_callback<void(uint32_t)> callback);
 
   unique_byte_buffer_t& operator[](uint32_t sn)
   {
diff --git a/lib/src/upper/pdcp_entity_lte.cc b/lib/src/upper/pdcp_entity_lte.cc
index b3dbefd00..c42740e2e 100644
--- a/lib/src/upper/pdcp_entity_lte.cc
+++ b/lib/src/upper/pdcp_entity_lte.cc
@@ -782,10 +782,10 @@ undelivered_sdus_queue::undelivered_sdus_queue(srslte::task_sched_handle task_sc
   }
 }
 
-bool undelivered_sdus_queue::add_sdu(uint32_t                             sn,
-                                     const srslte::unique_byte_buffer_t&  sdu,
-                                     uint32_t                             discard_timeout,
-                                     const std::function<void(uint32_t)>& callback)
+bool undelivered_sdus_queue::add_sdu(uint32_t                              sn,
+                                     const srslte::unique_byte_buffer_t&   sdu,
+                                     uint32_t                              discard_timeout,
+                                     srslte::move_callback<void(uint32_t)> callback)
 {
   assert(not has_sdu(sn) && "Cannot add repeated SNs");
 
@@ -824,7 +824,7 @@ bool undelivered_sdus_queue::add_sdu(uint32_t                             sn,
   sdus[sn].sdu->N_bytes    = sdu->N_bytes;
   memcpy(sdus[sn].sdu->msg, sdu->msg, sdu->N_bytes);
   if (discard_timeout > 0) {
-    sdus[sn].discard_timer.set(discard_timeout, callback);
+    sdus[sn].discard_timer.set(discard_timeout, std::move(callback));
     sdus[sn].discard_timer.run();
   }
   sdus[sn].sdu->set_timestamp(); // Metrics