diff --git a/.npmignore b/.npmignore
index 590ff67..2f8261c 100644
--- a/.npmignore
+++ b/.npmignore
@@ -13,3 +13,4 @@ circle.yml
 npm-debug.log
 .compiled
 ISSUE_TEMPLATE.md
+*.tgz
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb57fe6..1b89139 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 6.4.2
+
+* Fixed some issues with MockNgRedux and the select dectorators. See https://github.com/angular-redux/store/issues/413 for details.
+
 # 6.4.1
 
 * Fixed a memory leak with `@select`, `@select$`. See https://github.com/angular-redux/example-app/issues/34 for details.
diff --git a/package.json b/package.json
index 10a596e..f3db402 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@angular-redux/store",
-  "version": "6.4.1",
+  "version": "6.4.2",
   "description": "Angular 2 bindings for Redux",
   "main": "./lib/src/index.js",
   "scripts": {
diff --git a/src/components/ng-redux.ts b/src/components/ng-redux.ts
index 8e7e8ec..79aecfa 100644
--- a/src/components/ng-redux.ts
+++ b/src/components/ng-redux.ts
@@ -18,11 +18,11 @@ import 'rxjs/add/operator/map';
 import 'rxjs/add/operator/filter';
 import 'rxjs/add/operator/distinctUntilChanged';
 import 'rxjs/add/operator/switchMap';
-import { Selector, PathSelector, resolveToFunctionSelector } from './selectors';
+import { Selector, PathSelector, Comparator, resolveToFunctionSelector } from './selectors';
 import { assert } from '../utils/assert';
 import { SubStore } from './sub-store';
 import { enableFractalReducers } from './fractal-reducer-map';
-import { ObservableStore, Comparator } from './observable-store';
+import { ObservableStore } from './observable-store';
 
 export class NgRedux<RootState> implements ObservableStore<RootState> {
   /** @hidden */
diff --git a/src/components/observable-store.ts b/src/components/observable-store.ts
index 193785b..394fa04 100644
--- a/src/components/observable-store.ts
+++ b/src/components/observable-store.ts
@@ -1,8 +1,6 @@
 import { Store, Reducer } from 'redux';
 import { Observable } from 'rxjs/Observable';
-import { Selector, PathSelector } from './selectors';
-
-export type Comparator = (x: any, y: any) => boolean;
+import { Selector, PathSelector, Comparator } from './selectors';
 
 /**
  * This interface represents the glue that connects the
diff --git a/src/components/selectors.ts b/src/components/selectors.ts
index d198a20..249606c 100644
--- a/src/components/selectors.ts
+++ b/src/components/selectors.ts
@@ -1,5 +1,8 @@
 import { getIn } from '../utils/get-in';
+import { Observable } from 'rxjs/Observable';
 
+export type Comparator = (x: any, y: any) => boolean;
+export type Transformer<RootState, V> = (store$: Observable<RootState>) => Observable<V>
 export type PropertySelector = string | number | symbol;
 export type PathSelector = (string | number)[];
 export type FunctionSelector<RootState, S> = ((s: RootState) => S);
diff --git a/src/components/sub-store.ts b/src/components/sub-store.ts
index c85b206..c0fbbae 100644
--- a/src/components/sub-store.ts
+++ b/src/components/sub-store.ts
@@ -7,10 +7,11 @@ import {
   Selector,
   PropertySelector,
   FunctionSelector,
+  Comparator,
   resolveToFunctionSelector,
 } from './selectors';
 import { NgRedux } from './ng-redux';
-import { ObservableStore, Comparator } from './observable-store';
+import { ObservableStore, } from './observable-store';
 import { registerFractalReducer, replaceLocalReducer } from './fractal-reducer-map';
 
 /** @hidden */
diff --git a/src/decorators/select.spec.ts b/src/decorators/select.spec.ts
index 251b70c..950409e 100644
--- a/src/decorators/select.spec.ts
+++ b/src/decorators/select.spec.ts
@@ -7,6 +7,7 @@ import 'rxjs/add/operator/take';
 
 import { NgRedux } from '../components/ng-redux';
 import { select, select$ } from './select';
+import { selectionMap } from '../utils/selection-map';
 
 class MockNgZone { run = fn => fn() }
 
@@ -24,6 +25,7 @@ describe('Select decorators', () => {
 
   beforeEach(() => {
     targetObj = {};
+    selectionMap.reset();
     ngRedux = new NgRedux(mockNgZone);
     ngRedux.configureStore(rootReducer, defaultState);
   });
diff --git a/src/decorators/select.ts b/src/decorators/select.ts
index 6be0ca7..ad2a9e2 100644
--- a/src/decorators/select.ts
+++ b/src/decorators/select.ts
@@ -1,8 +1,8 @@
 import { Observable } from 'rxjs/Observable';
 import 'rxjs/add/operator/let'
 import { NgRedux } from '../components/ng-redux';
-import { Selector } from '../components/selectors';
-import { Comparator } from '../components/observable-store';
+import { Selector, Comparator, Transformer } from '../components/selectors';
+import { selectionMap } from '../utils/selection-map';
 
 /**
  * Selects an observable from the store, and attaches it to the decorated
@@ -20,7 +20,6 @@ export function select<T>(
   comparator?: Comparator) {
 
   return function decorate(target: any, key: string): void {
-    let result;
     let bindingKey = selector;
     if (!selector) {
       bindingKey = (key.lastIndexOf('$') === key.length - 1) ?
@@ -29,10 +28,12 @@ export function select<T>(
     }
 
     function getter() {
-      if (NgRedux.instance && !result) {
-        result = NgRedux.instance.select(bindingKey, comparator);
+      let selection = selectionMap.get(bindingKey, null, comparator);
+      if (NgRedux.instance && !selection) {
+        selection = NgRedux.instance.select(bindingKey, comparator);
+        selectionMap.set(bindingKey, null, comparator, selection);
       }
-      return result;
+      return selection;
     }
 
     // Replace decorated property with a getter that returns the observable.
@@ -46,8 +47,6 @@ export function select<T>(
   };
 }
 
-export type Transformer<RootState, V> = (store$: Observable<RootState>) => Observable<V>
-
 /**
  * Selects an observable using the given path selector, and runs it through the given
  * transformer function. A transformer function takes the store observable as an input and
@@ -63,14 +62,15 @@ export function select$<T>(
   comparator?: Comparator) {
 
   return function decorate(target: any, key: string): void {
-    let result;
     function getter() {
-      if (NgRedux.instance && !result) {
-        result = NgRedux.instance.select(selector)
+      let selection = selectionMap.get(selector, transformer, comparator);
+      if (NgRedux.instance && !selection) {
+        selection = NgRedux.instance.select(selector)
           .let(transformer)
           .distinctUntilChanged(comparator);
+        selectionMap.set(selector, transformer, comparator, selection);
       }
-      return result;
+      return selection;
     }
 
     // Replace decorated property with a getter that returns the observable.
diff --git a/src/index.ts b/src/index.ts
index a4caac6..c778b26 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -4,12 +4,15 @@ import {
   PathSelector,
   PropertySelector,
   FunctionSelector,
+  Comparator,
+  Transformer,
 } from './components/selectors';
-import { ObservableStore, Comparator } from './components/observable-store';
+import { ObservableStore } from './components/observable-store';
 import { DevToolsExtension } from './components/dev-tools';
 import { select, select$ } from './decorators/select';
 import { dispatch } from './decorators/dispatch';
 import { NgReduxModule } from './ng-redux.module';
+import { selectionMap } from './utils/selection-map';
 
 // Warning: don't do this:
 //  export * from './foo'
@@ -22,10 +25,12 @@ export {
   PropertySelector,
   FunctionSelector,
   Comparator,
+  Transformer,
   NgReduxModule,
   DevToolsExtension,
   select,
   select$,
   dispatch,
   ObservableStore,
+  selectionMap,
 };
diff --git a/src/utils/selection-map.ts b/src/utils/selection-map.ts
new file mode 100644
index 0000000..319b6ff
--- /dev/null
+++ b/src/utils/selection-map.ts
@@ -0,0 +1,44 @@
+import { Observable } from 'rxjs/Observable';
+import { Selector, Comparator, Transformer } from '../components/selectors';
+
+const toKey = (val: Object | Array<any> | Function | String) =>
+  val ? val.toString() : '';
+
+const computeKey = (
+  selector: Selector<any, any>,
+  transformer: Transformer<any, any>,
+  comparator: Comparator) =>
+  `s:${toKey(selector)}:t:${toKey(transformer)}:c:${toKey(comparator)}`;
+
+/**
+ * Used to pool Observables created by @select and @select$. This
+ * avoids memory leaks and improves efficiency.
+ * @hidden
+ */
+export class SelectionMap {
+  private _map: { [id: string]: Observable<any> } = {};
+
+  set(
+    selector: Selector<any, any>,
+    transformer: Transformer<any, any>,
+    comparator: Comparator,
+    selection: Observable<any>): void {
+    const key = computeKey(selector, transformer, comparator);
+    this._map[key] = selection;
+  }
+
+  get(
+    selector: Selector<any, any>,
+    transformer: Transformer<any, any>,
+    comparator: Comparator): Observable<any> {
+    const key = computeKey(selector, transformer, comparator);
+    return this._map[key];
+  }
+
+  reset() {
+    this._map = {};
+  }
+}
+
+/** @hidden */
+export const selectionMap = new SelectionMap();
diff --git a/testing/ng-redux.mock.ts b/testing/ng-redux.mock.ts
index c53a4be..8b36abe 100644
--- a/testing/ng-redux.mock.ts
+++ b/testing/ng-redux.mock.ts
@@ -4,6 +4,7 @@ import {
   Comparator,
   ObservableStore,
   PathSelector,
+  selectionMap,
 } from '@angular-redux/store';
 import { Reducer, Action } from 'redux';
 import { Observable } from 'rxjs/Observable';
@@ -53,6 +54,7 @@ export class MockNgRedux<RootState> extends MockObservableStore<RootState> {
    */
   static reset(): void {
     MockNgRedux.mockInstance.reset();
+    selectionMap.reset();
   }
 
   /** @hidden */