https://imgur.com/a/CD6Ignm
Cleaning my rifle tonight. The cleaning  brush( old gi cleaning kit) came loose and stuck in there.I tried to push it out with the unattached  cleaning rod. I wonder if I scratch the barrel with rod. I notice there is a  small horizontal scratch at the front section of the barrel. Did I mess up the barrel? Will it affect the accuracy?

Was your cleaning rod Brass, Aluminum, or Stainless Steel? Brass and Aluminum is softer, and most likely will not scratch. Steel can and will.

Get rid of that carbon steel hard as fuck GI cleaning kit. Stop using brushes at all, there's never a good reason to use them. Patches and chemical solvents with plastic/aluminum/brass jags and a ceramic coated 1-piece cleaning rod like a Dewey rod with a bore guide and then a chamber brush. A scratch probably won't hurt unless it's all the way at the muzzle but it's definitely not going to help anything.

Always and only use brass or aluminum rods for cleaning gun barrels..

If you have a local Walmart that sells gun equipment/supplies find a bore snake or an air gun cable system for 22 caliber. Either of these work great and are less prone to do any bore damage.

GI steel rod kits are not gun friendly. They work, but remember that they weren't good for the gun, only good for the government and what it wants.

One piece carbon fiber Tipton cleaning rods are all that I use.  Been using these for years....no issues

This.  And bronze brushes will NOT harm a barrel, not even a stainless match barrel.  Nylon brushes are for use with copper (ammonia-based) solvents, as ammonia chemically reacts with bronze and destroy the bristles.  The resultant green discoloration also produces a false indicator of copper buildup in the bore.

https://riflebarrels.com/support/centerfire-maintenance/

Do use a bore guide.  Always.

OP, from the photo, it looks like you have a basic government profile mass produced barrel.  Chances are that you will not see a change in accuracy, but ditch the GI kit.

That horizontal scratch is the gas port.

+1 on it being the gas port.   I never recommend aluminum rods though.  They strip out from brushes and jags, and are more prone to bending in the barrel.

Bore snakes, never an issue.

Shoot it OP and check your groupings.  FWIW I have been using USGI cleaning kits on my sticks ever since I cut my teeth on the M16/AR platform in the Marine Corps and have never had an issue because if you use them properly they work and work well.

wait, people are cleaning the bore?

In the future, it's probably good to keep in mind that you can re-attach a cleaning rod to a brush or jag that is stuck in the bore.  You don't have to poke the thing out.

https://www.boretech.com/products/proof-positive-bore-stix-223-cal-cf

Put a few hundred rounds of ball ammo through it. If you somehow managed to create a defect in the barrel (which I doubt) it'll lap it down

This, I have the USGI ones if they fit in the buttstock, but I use boresnakes on all mine, always.

William

First off, as others have mentioned, ditch the GI kit.  Get a 1-piece rod, ideally a coated one like a Dewey (all I use).  A one-time purchase you'll have for many years, and will almost make cleaning enjoyable (a lie).  In 15 years I've come to learn that cleaning less often is better.  You lessen your chances of things like this, and you gain little, unless you notice a drop in accuracy or reliability.  AR-15's take a good amount of fouling for that to occur.  Just keep it oiled during each outing.  I'm anal with cleanliness in general, but I've gotten much more enjoyment out of my rifles cleaning them every 500-1,000 rds or so.

That being said, your barrel is probably fine, and a good chance that's the gas port.  I guess I'm just hear to type out what everyone else already said: Go shoot it, if it shoots like it did yesterday, then carry on.

Oh, and a +1 for the bore guide.  Another item that's relatively inexpensive, will last you many years, and will make your life easier.