Just installed a new Faxon 6.5 Grendel barrel in my upper. I decided to run some oiled patches down the barrel before putting it in the safe.
Well, I put together my 3 piece aluminum cleaning rod and ran a patch through the barrel. Felt snug, but nothing that needed force. I looked over and realized I had used the 30 cal rod instead of the 22 cal rod. I used calipers and measured the 30 cal rod. It's roughly. 250" while the interior of the 6.5 is .260", not sure if I measured off the lands or grooves.
Did I ruin the barrel or am I over thinking?

No  Barrel's fine.  Steel is harder and stronger than aluminum.  you're good.

If you lived in my AO I'd come over and bore scope it with you.
But..  we're 1500 miles apart

I also think that you're fine, if a gunsmith in your area has a bore scope,
take it over, scope it, and see if you have any damage.

Like everyone else has said your barrel should be fine, but going forward you might want to ditch the 30 cal rod. I only own and use 22 cal cleaning rods for this reason.

Wasn't one of the site sponsors a bore scope vendor?  I recall, they had really reasonable bore scopes.  I don't see them listed above or below anymore.

Teslong, IIRC.

That was it.  Thanks, SB

^This

Shoot it and see. You'll know in short order.

You say you have a 3 piece aluminium rod. Did you PUSH it through the bore or PULLED it from the bore? My only advice is never PUSH a rod through a bore and always try to PULL from it. That means dropping it down the bore and pulling it out from the other end. It's for 1 a lot easier and second a lot more safer because the rod isn't bending. The way you do it is loosen the section a little so it's not tight, drop it down the bore, then pull from the opposite end. The joints will tighten in the bore and you wipe and loosen the joints before dropping it back down. If you push PUSH the rod through, then buy a 1 piece rod and a bore guide. The bore guide is not totally needed but usually 1piece rods will be coated so it bending would be fine.

But I wouldn't really stress it that much. I would just go shoot it and see how it shoots.

Try to follow this video...

One of these days I'll get a one price rod.
I start at the chamber, but after I push the rod forward, I pull it back......

I forgot to post after I shoot it. It tucked, I mean real bad groups. I reached out to Faxon and they suggested that I remove the barrel and reinstall it, that some times the first install didn't go well. Did have some cycling issues, so I'm wondering if this is the case. I just haven't had the time yet to do that. My plan is to in a few months and try it out again.

If you can hand push a cleaning rod through a barrel hard enough to wreck it, I want to hire you to open stuck pickle jars for my grandmother (we all know those require super human strength).

No, you don't want your cleaning rod dragging up and down your match grade, sub half MOA barrel. That said, while there are nearly endless alloys of each so nothing conclusive can be said, aluminum is generally softer than copper and certainly didn't harm the barrel.

People place a lot of unnecessary focus on cleaning rods. My personal experience was in the military arena. As a private and junior NCO, a lot of time was spent cleaning M16A2s and early M4s. Endless cleaning. We'd jam army issue steel cleaning rods down those barrels until patches came out white. Then, when weapons were spotless, we'd stick a rod in the barrel with nothing on the end and just push it in and pull it out to make it look like we were doing something.

I'd take that same rifle on range day, stack 3 rounds in 1 hole on a 25M composite zero target and shoot 30/30 as far as 300M. Now, that's not sub MOA per se but it was also using 3 MOA M855 ball.

Don't fall for the idea that your barrel is a gentle flower. It's an AR. Certainly take care of it and don't do what Army privates do, but don't worry that you've gone and destroyed it because you pushed a less than optimal aluminum rod through it.

You also forget the barrel in the military and elsewhere are considered disposable items. So cleaning it roughly, while not ideal, is expected and easily replaced by any armorer. I imagine for a personal owner though you don't want to potentially cause undue wearing. While it's doubtful you'll ruin it in one sitting, there's a good chance overtime it could wear out the barrel prematurely. Just by how much? I don't know or if it is even something that is measurable.

One thing that is for sure though is that you'll eventually wear the barrel out no matter what you do or how careful you are about cleaning it.

As far as rifles being delicate flowers, I disagree with you. I think people who treat their stuff like it's worth a million bucks and take care of it are better than the regular people you can find. In the end, it probably doesn't matter if they treat it like it was worth a million bucks or a 5 dollar cheap hooker because it'll eventually wear out.

From my own study with a bore scope, I did test a brass brush vs just using chemical alone. I found something rather interesting about it. At about round 500-1000, the brass brush would cause noticeable wearing on the throat area but the bore with just chemical, the throat would look pretty well intact with nothing noticable. At about round count 2000ish, both would appear nearly the same in terms of throat wear. I'm not entirely sure if that means anything at all but I do notice some more wearing in from the brash brush. I still use a brass brush though but I'm more careful about how many times I'm passing it through the barrel.

With today's world, I really think using a solid chemical product is much better than it was. I now use Boretech but I have used wipeout and found that both solutions would work fairly well in getting rid of just 90% of the stuff with just chemical alone and depending on how much time you let it soak, it can get up to 99% with the only areas it can't really touch is the gas port where it starts to wear.

I don't disagree with you in spirit or in practice. I do disagree with the premise that military armorers regularly and easily replace barrels. I was the unit armorer for a few years. I rarely sent M16 or M4s for rebarrel. Perhaps 3 or 4 times. It was exceedingly rare. The reason was usually external damage from being run over by a vehicle or something of the sort.

My real point was that for the OP, running this rod through his barrel, this time, didn't ruin it. Of course you should take care of your weapons. I'm definitely not advocating for neglectful treatment. I'm simply saying that people get really worried about bore guides and carbon fiber rods and destroying their barrels in a rifle that is so much more resilient than they give it credit for and, frankly, is not a Tikka or Bergara or Christensen, where even for their lower price you can expect to print dime sized groups. The tools used to clean an AR are rarely going to result in noticeable accuracy changes for the average shooter, as long as they're cleaning it properly and giving it appropriate lubrication.