I have the same Mountaineer in the same color. You may need to do a fix on the bare primer ., at least I had a problem with the bare primer setup . Sucks dealing with Stuck primers when all you want to do is shoot. Hopefully you don’t have that issue but it’s a possibility.
You will definitely like the Mountaineer. I think you will find 500 yard accuracy is not a problem.
Post some pics when you get a chance