diff --git a/spec/grammars-spec.coffee b/spec/grammars-spec.coffee
index 82a29892a..a36a10170 100644
--- a/spec/grammars-spec.coffee
+++ b/spec/grammars-spec.coffee
@@ -142,9 +142,13 @@ describe "the `grammars` global", ->
         expect(atom.grammars.selectGrammar('Rakefile', '').scopeName).toBe 'source.coffee'
         expect(atom.grammars.selectGrammar('Cakefile', '').scopeName).toBe 'source.ruby'
 
-      it "favors grammars with matching first-line-regexps even if custom file types match the file", ->
+      it "favors user-defined file types over grammars with matching first-line-regexps", ->
         atom.config.set('core.customFileTypes', 'source.ruby': ['bootstrap'])
-        expect(atom.grammars.selectGrammar('bootstrap', '#!/usr/bin/env node').scopeName).toBe 'source.js'
+        expect(atom.grammars.selectGrammar('bootstrap', '#!/usr/bin/env node').scopeName).toBe 'source.ruby'
+
+  describe "when there is a grammar with a first line pattern, the file type of the file is known, but from a different grammar", ->
+    it "favors file type over the matching pattern", ->
+      expect(atom.grammars.selectGrammar('foo.rb', '#!/usr/bin/env node').scopeName).toBe 'source.ruby'
 
   describe ".removeGrammar(grammar)", ->
     it "removes the grammar, so it won't be returned by selectGrammar", ->
diff --git a/src/grammar-registry.coffee b/src/grammar-registry.coffee
index 4a5352275..383d4d776 100644
--- a/src/grammar-registry.coffee
+++ b/src/grammar-registry.coffee
@@ -36,21 +36,21 @@ class GrammarRegistry extends FirstMate.GrammarRegistry
       if score > highestScore or not bestMatch?
         bestMatch = grammar
         highestScore = score
-      else if score is highestScore and bestMatch?.bundledPackage
-        bestMatch = grammar unless grammar.bundledPackage
     bestMatch
 
   # Extended: Returns a {Number} representing how well the grammar matches the
   # `filePath` and `contents`.
   getGrammarScore: (grammar, filePath, contents) ->
+    return Infinity if @grammarOverrideForPath(filePath) is grammar.scopeName
+
     contents = fs.readFileSync(filePath, 'utf8') if not contents? and fs.isFileSync(filePath)
 
-    if @grammarOverrideForPath(filePath) is grammar.scopeName
-      2 + (filePath?.length ? 0)
-    else if @grammarMatchesContents(grammar, contents)
-      1 + (filePath?.length ? 0)
-    else
-      @getGrammarPathScore(grammar, filePath)
+    score = @getGrammarPathScore(grammar, filePath)
+    if score > 0 and not grammar.bundledPackage
+      score += 0.25
+    if @grammarMatchesContents(grammar, contents)
+      score += 0.125
+    score
 
   getGrammarPathScore: (grammar, filePath) ->
     return -1 unless filePath