Inconsistent Rifling Affecting Accuracy?

[Sbokor]

So I have discovered something and wonder if it affects accuracy enough to worry about.

I got a new toy for Christmas (who didn't) which is a Teslong bore scope. After hooking it up to my laptop I grabbed a 300BO AR barrel that was sitting on the shelf. What I noticed was when looking at where the rifling starts is inconsistency. Now it is a gun show barrel that I have no idea of the manufacture but I suspected that it was low end so I am not worried about it as I have since replaced it. So since the rifling is inconsistent I can imagine the it affects accuracy, the question I have is would this be significant or minor. I suspect at close distance not much issue but at longer distance it would become more pronounced.

This first picture shows the rifling starting at the beginning of the bore

The second picture shows the second rifling starting at near the beginning of the bore but less pronounced

The last picture shows the third rifling starting much farther into the bore. The next two where similar.

 

[1moaoff]

Are you sure its rifling discrepancy or could it be chamber isn't aligned with bore

 

[b6graham]

how does it shoot

 

[Steel head]

Are you sure its rifling discrepancy or could it be chamber isn't aligned with bore

It’s probably this and I’m always shocked at how it can be worse than that and still stack shots.

how does it shoot

The $10,000 question.

 

[b6graham]

It’s probably this and I’m always shocked at how it can be worse than that and still stack shots.


The $10,000 question.

and the one every single person who gets a borescope for the first time should ask themselves when shoving it down the barrel

 

[Steel head]

and the one every single person who gets a borescope for the first time should ask themselves when shoving it down the barrel

So true.

 

[loveha]

It's a cleaning tool. Quit over thinking things.

 

[S197]

Just remember, bore scopes are a great tool but they can be very misleading.

 

[Sbokor]

Are you sure its rifling discrepancy or could it be chamber isn't aligned with bore

I am not sure and may never be given the measuring tools I have. The barrel gives me about 1 MOA with the right load. Not bad but not great which is why I posed the question

 

[clcustom1911]

I am not sure and may never be given the measuring tools I have. The barrel gives me about 1 MOA with the right load. Not bad but not great which is why I posed the question

So, to summarize:

Your rifle shoots 1moa with a good load, you discover whatever you discover in the barrel, then ask if it will still shoot good?

 

[smoothy8500]

It's a cleaning tool. Quit over thinking things.

Probably the only legitimate use for a borescope, other than searching for termites in the walls....

 

[lennyo3034]

An .300 BO AR barrel purchased at a gun show shoots 1 MOA? That’s a win right there regardless of what the rifleing looks like.

 

[b2lee]

A borescope has several legitimate uses.

1. Cleaning aide to make sure you got everything.
2. Look for a carbon ring.
3. Use on a barrel of a gun your are trying to buy and use it as a way to pick it apart and talk the dude down a few hundred bucks.
4. See how an empty piece of sized brass fits in the chamber...but from the muzzle end...very cool.
5. Record firing pin timing and see firing pin protrusion in real time.
6. To see that 300BO bullet stuck in your 5.56 barrel because you inserted the wrong mag.
7. As a gag gift to a friend that has OCD and you want to drive them bonkers.
8. To see the inside of your brass....looking for case head separation or flash hole burrs.

 

[__JR__]

Borescoping a barrel without the knowledge or training is likely about as reliable as self colonoscopy..Same tool.

 

[308pirate]

So I have discovered something and wonder if it affects accuracy enough to worry about.

I got a new toy for Christmas (who didn't) which is a Teslong bore scope. After hooking it up to my laptop I grabbed a 300BO AR barrel that was sitting on the shelf. What I noticed was when looking at where the rifling starts is inconsistency. Now it is a gun show barrel that I have no idea of the manufacture but I suspected that it was low end so I am not worried about it as I have since replaced it. So since the rifling is inconsistent I can imagine the it affects accuracy, the question I have is would this be significant or minor. I suspect at close distance not much issue but at longer distance it would become more pronounced.

This first picture shows the rifling starting at the beginning of the bore

View attachment 7514613

The second picture shows the second rifling starting at near the beginning of the bore but less pronounced
View attachment 7514620
The last picture shows the third rifling starting much farther into the bore. The next two where similar.
View attachment 7514622

Borescoping a barrel without the knowledge or training is likely about as reliable as self colonoscopy..Same tool.

OP your answer in the other post I quote here. You might want to look at user _JR_'s signature...............

 

[__JR__]

OP your answer in the other post I quote here. You might want to look at user _JR_'s signature...............

My point is you bought a barrel at a gun show, stuck an endoscope in it months later, then posted pictures of the throat in a public forum and asked if it will shoot. If you are concerned by what's in your 'I don't know' column to move to your 'I think I know because I googled it' column, next time bring your borescope to the gun show and pick your barrel from there. Otherwise, shove a pill in that pig and see where she takes you. 300BO not known for great target accuracy with FA, but range limit and application is often suitable enough that a $100 barrel from gun show may still be a great buy.

Later

 

[Sbokor]

Are you sure its rifling discrepancy or could it be chamber isn't aligned with bore

BTW thanks for the comment. I had not considered this possibility.

 

[clcustom1911]

BTW thanks for the comment. I had not considered this possibility.

And your barrel still shoots 1 MOA, so it doesn't matter.