Damage to Rifling!

[yote doctor]

AR15 with only 75 rounds out (with correct break-in) and noticed a nick in the rifling. After looking a little longer it turns out to be a small bur right on the edge of the rifling. Its pretty easy to notice just glancing down the tube. I first noticed after I had cleaned it and later my grouping went from .25 to 1.0 or worse!

I have never damage a rifle by cleaning but dont know what else could have caused this. Tried brushing it, but no luck. Off to the smith?

Any suggestions?

 

[Kevin Thomas]

Yote Doctor,

where, exactly is this burr? Not exactly uncommon to see something like this around the gas hole, and it may polish out. You mentioned groups going from .25" to 1", but you didn't say how many rounds are through the barrel, or how well established that previous .25" standard of accuracy was. Need a bit more information here.

 

[yote doctor]

Thanks for the reply.

I did mention above, there has been 75 rounds shot out of this rifle. And I think you are right. With further investigation it does appear to be at the gas hole. And as far as the grouping size, its been consistently shooting small groups with two different bullets/loads. 3 and 5 shot groups at no more than .5.

Took it out this weekend and It was all over the place. And 1" was the best group I could get. Few worse than that so I didnt even want to take a measurement.

Does that help?

 

[Kevin Thomas]

Yote Doc,

Still a lot of things that are possible here, but frankly, I'd suggest that after just 75 rounds through the gun you just don't have enough baseline data to say that the gun has opened up. Play with it a bit more and see what it does with one standard load, and then start changing things, one vaiable at a time.

What type of AR is this? A standard rifle, or some version of a match gun? Floated barrel, or standard handguards? It the barrel's not floated, that'd be the first thing I'd want to change if I wanted a real shooter. Of all the things you can do to make an AR shoot, the floating barrel is probably #1 on the list, closely followed by a really good barrel and a good trigger.