Оберните RecyclerView в RelativeLayout и применяйте LayoutParams к нему.
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<android.support.v7.widget.RecyclerView
android:id="@+id/images"
android:layout_width="wrap_content"
android:layout_height="360dp"
>
</android.support.v7.widget.RecyclerView>
</Relativelayout>
RelativeLayout.LayoutParams lp =
new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, 500);
recyclerView.setLayoutParams(lp);