Another Build Question - Upper Receiver

So I am seeing some upper receivers that specify the caliber and some that don’t. I had assumed that the stripped upper was not caliber specific. Just want to double check so I get the right thing for the 6.5 Grendel.


For the most part, a stripped upper receiver is non caliber specific. The onlhy thing that needs to be different on the 6.5 grendal, other than the barrel, is the bolt.


Sometimes though they will make larger ejection port openings. This is for the larger cases being fired. Like the 6.8 SPC and others. Besides that, go will known top of the line brands. (This doesn’t mean expensive)


If your just buying a striped upper most will do the job. The one I have is a standard ar-15 upper, and has standard dimensions.
One good point to bring up, not to go down into a rabbit hole; is the development of the 6.5 Grendel chamber and the difference that makes in bolt selection. The two different bolts are type 1, and type 2. The one I built is a type 2 referring to the depth the bolt face is cut. Type 1 are cut to .125”, and type 2 bolts are cut to .136” it is important to have the correct bolt for your barrel otherwise you could have a really bad day. Measure twice cut once. If your unsure of the barrel spec call the barrel manufacturers and ask. The bolt is simple to figure out! Remove the extractor. There should be a stamp for the type 2 like this!

I hope this information helps people with their builds.
Here is a video on the topic.

Remember be safe, and have fun!


Yes! Really good point!!


I got the Faxon BCG since I got the Faxon barrel. It’s type 2, but it didn’t occur to me to check the barrel for compatibility. Thanks. I’ll check that out.