diff --git a/capnp/capnp.pyx b/capnp/capnp.pyx
index b738f57..805eed0 100644
--- a/capnp/capnp.pyx
+++ b/capnp/capnp.pyx
@@ -37,6 +37,10 @@ ctypedef fused _DynamicStructReaderOrBuilder:
     _DynamicStructReader
     _DynamicStructBuilder
 
+ctypedef fused _DynamicSetterClasses:
+    C_DynamicList.Builder
+    C_DynamicStruct.Builder
+
 def _make_enum(enum_name, *sequential, **named):
     enums = dict(zip(sequential, range(len(sequential))), **named)
     reverse = dict((value, key) for key, value in enums.iteritems())
@@ -259,43 +263,6 @@ cdef class _DynamicListBuilder:
         index = index % size
         return self._get(index)
 
-    cdef _setitemInt(self, index, value):
-        cdef C_DynamicValue.Reader temp
-        if value < 0:
-            temp = C_DynamicValue.Reader(<long long>value)
-        else:
-            temp = C_DynamicValue.Reader(<unsigned long long>value)
-        self.thisptr.set(index, temp)
-
-    cdef _setitemDouble(self, index, value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(<double>value)
-        self.thisptr.set(index, temp)
-
-    cdef _setitemBool(self, index, value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(<cbool>value)
-        self.thisptr.set(index, temp)
-
-    cdef _setitemString(self, index, value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(<char*>value)
-        self.thisptr.set(index, temp)
-
-    cdef _setitemVoid(self, index):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(VOID)
-        self.thisptr.set(index, temp)
-
-    cdef _setitemList(self, index, value):
-        builder = toPython(self.thisptr.init(index, len(value)), self._parent)
-        for (i, v) in enumerate(value):
-            builder[i] = v
-
-    cdef _setitemDynamicStructBuilder(self, index, _DynamicStructBuilder value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(value.thisptr.asReader())
-        self.thisptr.set(index, temp)
-
-    cdef _setitemDynamicStructReader(self, index, _DynamicStructReader value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(value.thisptr)
-        self.thisptr.set(index, temp)
-
     def __setitem__(self, index, value):
         # TODO: share code with _DynamicStructBuilder.__setattr__
         
@@ -303,26 +270,7 @@ cdef class _DynamicListBuilder:
         if index >= size:
             raise IndexError('Out of bounds')
         index = index % size
-        value_type = type(value)
-
-        if value_type is int or value_type is long:
-            self._setitemInt(index, value)
-        elif value_type is float:
-            self._setitemDouble(index, value)
-        elif value_type is bool:
-            self._setitemBool(index, value)
-        elif value_type is str:
-            self._setitemString(index, value)
-        elif value_type is list:
-            self._setitemList(index, value)
-        elif value is None:
-            self._setitemVoid(index)
-        elif value_type is _DynamicStructBuilder:
-            self._setattrDynamicStructBuilder(index, value)
-        elif value_type is _DynamicStructReader:
-            self._setattrDynamicStructReader(index, value)
-        else:
-            raise ValueError("Non primitive type")
+        _setDynamicField(self.thisptr, index, value, self._parent)
 
     def __len__(self):
         return self.thisptr.size()
@@ -447,6 +395,45 @@ cdef toPython(C_DynamicValue.Builder self, object parent):
     else:
         raise ValueError("Cannot convert type to Python. Type is unhandled by capnproto library")
 
+cdef C_DynamicValue.Reader _extractDynamicStructBuilder(_DynamicStructBuilder value):
+    return C_DynamicValue.Reader(value.thisptr.asReader())
+
+cdef C_DynamicValue.Reader _extractDynamicStructReader(_DynamicStructReader value):
+    return C_DynamicValue.Reader(value.thisptr)
+
+cdef _setDynamicField(_DynamicSetterClasses thisptr, field, value, parent):
+    cdef C_DynamicValue.Reader temp
+    value_type = type(value)
+
+    if value_type is int or value_type is long:
+        if value < 0:
+           temp = C_DynamicValue.Reader(<long long>value)
+        else:
+           temp = C_DynamicValue.Reader(<unsigned long long>value)
+        thisptr.set(field, temp)
+    elif value_type is float:
+        temp = C_DynamicValue.Reader(<double>value)
+        thisptr.set(field, temp)
+    elif value_type is bool:
+        temp = C_DynamicValue.Reader(<cbool>value)
+        thisptr.set(field, temp)
+    elif value_type is str:
+        temp = C_DynamicValue.Reader(<char*>value)
+        thisptr.set(field, temp)
+    elif value_type is list:
+        builder = toPython(thisptr.init(field, len(value)), parent)
+        for (i, v) in enumerate(value):
+            builder[i] = v
+    elif value is None:
+        temp = C_DynamicValue.Reader(VOID)
+        thisptr.set(field, temp)
+    elif value_type is _DynamicStructBuilder:
+        thisptr.set(field, _extractDynamicStructBuilder(value))
+    elif value_type is _DynamicStructReader:
+        thisptr.set(field, _extractDynamicStructReader(value))
+    else:
+        raise ValueError("Non primitive type")
+
 cdef class _DynamicStructReader:
     """Reads Cap'n Proto structs
 
@@ -567,65 +554,8 @@ cdef class _DynamicStructBuilder:
     def __getattr__(self, field):
         return self._get(field)
 
-    cdef _setattrInt(self, field, value):
-        cdef C_DynamicValue.Reader temp
-        if value < 0:
-           temp = C_DynamicValue.Reader(<long long>value)
-        else:
-           temp = C_DynamicValue.Reader(<unsigned long long>value)
-        self.thisptr.set(field, temp)
-
-    cdef _setattrDouble(self, field, value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(<double>value)
-        self.thisptr.set(field, temp)
-
-    cdef _setattrBool(self, field, value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(<cbool>value)
-        self.thisptr.set(field, temp)
-
-    cdef _setattrString(self, field, value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(<char*>value)
-        self.thisptr.set(field, temp)
-
-    cdef _setattrVoid(self, field):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(VOID)
-        self.thisptr.set(field, temp)
-
-    cdef _setattrList(self, field, value):
-        builder = toPython(self.thisptr.init(field, len(value)), self._parent)
-        for (i, v) in enumerate(value):
-            builder[i] = v
-
-    cdef _setattrDynamicStructBuilder(self, field, _DynamicStructBuilder value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(value.thisptr.asReader())
-        self.thisptr.set(field, temp)
-
-    cdef _setattrDynamicStructReader(self, field, _DynamicStructReader value):
-        cdef C_DynamicValue.Reader temp = C_DynamicValue.Reader(value.thisptr)
-        self.thisptr.set(field, temp)
-
     def __setattr__(self, field, value):
-        # TODO: share code with _DynamicListBuilder.__setitem__
-        value_type = type(value)
-
-        if value_type is int or value_type is long:
-            self._setattrInt(field, value)
-        elif value_type is float:
-            self._setattrDouble(field, value)
-        elif value_type is bool:
-            self._setattrBool(field, value)
-        elif value_type is str:
-            self._setattrString(field, value)
-        elif value_type is list:
-            self._setattrList(field, value)
-        elif value is None:
-            self._setattrVoid(field)
-        elif value_type is _DynamicStructBuilder:
-            self._setattrDynamicStructBuilder(field, value)
-        elif value_type is _DynamicStructReader:
-            self._setattrDynamicStructReader(field, value)
-        else:
-            raise ValueError("Non primitive type")
+        _setDynamicField(self.thisptr, field, value, self._parent)
 
     def _has(self, field):
         return self.thisptr.has(field)
diff --git a/capnp/capnp_cpp.pxd b/capnp/capnp_cpp.pxd
index f00f2c6..38e2e89 100644
--- a/capnp/capnp_cpp.pxd
+++ b/capnp/capnp_cpp.pxd
@@ -103,7 +103,7 @@ cdef extern from "capnp/dynamic.h" namespace " ::capnp":
             Builder(Builder &)
             DynamicValueForward.Builder get(char *)
             bint has(char *) except +ValueError
-            void set(char *, DynamicValueForward.Reader&) except +ValueError
+            void set(char *, DynamicValueForward.Reader) except +ValueError
             DynamicValueForward.Builder init(char *, uint size)
             DynamicValueForward.Builder init(char *)
             StructSchema getSchema()
@@ -130,7 +130,7 @@ cdef extern from "capnp/dynamic.h" namespace " ::capnp":
             Builder(Builder &)
             DynamicValueForward.Builder operator[](uint)
             uint size()
-            void set(uint index, DynamicValueForward.Reader& value) except +ValueError
+            void set(uint index, DynamicValueForward.Reader value) except +ValueError
             DynamicValueForward.Builder init(uint index, uint size) except +ValueError
             void adopt(uint, DynamicOrphan)
             DynamicOrphan disown(uint)