If I wanted to swap out a 5.56 barrel for a 6.5 Grendel, is it as simple as pulling the one barrel and installing the new one? I get I'll need a 6.5 bolt and magazine but other than that everything is interchangeable? So I could utilize the current hand rail, gas system, etc?

The only snag you might have is whether or not the gas block is the same inside diameter as your new barrel. Also, you may need a new gas tube (I always replace them). Your hand rail should fit.

Have you decided on the replacement barrel? If so, let us know what it is and what you currently have. That would make the advice a bit more exact.

Looking at an Anderson barrel, not sure about the current barrel. It's an American Tactical AR.

Your current barrel nut will work just fine. If your new barrel is the same OD for the gas block, it will work also. A word of advise here ...... I always purchase a new gas block and also a new gas tube. Unless you get fancy with 4-sided rails on the gas block you can replace them for under $50. Why? Because you can leave your old gas block on your old barrel and it will be there if you ever decide to use it again. Get a clamp-on gas block. They are much easier to deal with. I always replace the gas tube because it is $5 and I have seen them gummed up after being shot a lot and not cleaned well. As for the hand guard, unless the new gas block prevents it from fitting it should be no problem. I'm assuming it is a free float tube?

Unless you are going from one gas systen to another ... that is, from a carbine to a mid-length or vice verse you should be good to go.

Do you have an armorer's wrench, a torque wrench, and a vise clamp for the upper receiver? If not, you will need those things also.

If you can, post a pic of what you have now and a link to the barrel you are going to get.

Thanks Creedmoor, they'll both be carbine but I hear about getting a new one. I knew I'd need a wrench and clamp but not worried about those either.

Anything I do I always seek out as much info as I can gather. Of course, replacing an AR barrel isn't rocket science, but you might want to search youtube for a video on the conversion. There are numerous ones out there. It may remind you of something you have overlooked or bring to light something you haven't thought of.

Prepare properly and take your time. I may be doing the same thing very soon.

Warning, once you've danced with the Grendel you'll lose interest in your other ARs

Alexander Arms hard use bolt is hard to beat for a Grendel. Also make sure you get a bolt that matches your barrel, there are 2 depths used for the Grendel, one from the 7.62X39 and the deeper one for the Grendel SAAMI Spec barrels.

Also I like the Elander mags from Alexander Arms as well. For me they seem to work a little better than the C-Products mags from everyone else.