diff --git a/lib/lock_jar/domain/gem_dsl.rb b/lib/lock_jar/domain/gem_dsl.rb
index <HASH>..<HASH> 100644
--- a/lib/lock_jar/domain/gem_dsl.rb
+++ b/lib/lock_jar/domain/gem_dsl.rb
@@ -30,7 +30,7 @@ module LockJar
           builder.gem_dir = spec.gem_dir
           
           jarfile = File.join( spec.gem_dir, jarfile )
-          builder.file_path = "gem:#{spec.name}:#{jarfile.gsub( "#{spec.base_dir}/", "" )}"
+          builder.file_path = "gem:#{spec.name}:#{jarfile.gsub( "#{spec.base_dir}/", "" )}.lock"
           
           evaluate(builder, jarfile)
         end
track Jarfile.lock in lockfile merged