Rifling chatter

[hogpatrol]

Got my Lyman borecam and decided to check out an aftermarket barrel that wouldn't shoot well consistently. Photos show what was found. It looks like cutter hook chatter to me. Anyone else have an opinion.

 

[Dusty Stevens]

Hows it shoot?

 

[Ggmac]

Reamer marks after drilling , not unusual at all . How does it shoot , clean and how does it shoot dirty . We're you actually getting it clean before you got the Borescope ?

 

[hogpatrol]

Hows it shoot?

Not very well. I thought it was a good one when I first started shooting it but after 300 rounds of different loads, bullets, primers, powder, brass, seating depths, neck tension, etc., etc., could never get it to shoot two good groups in a row. I have several custom barrel rifles and none have given me the fits like this has. Needless to say, it's in my "tomato stake" category.

 

[hogpatrol]

Reamer marks after drilling , not unusual at all . How does it shoot , clean and how does it shoot dirty . We're you actually getting it clean before you got the Borescope ?

The chatter is in the grooves so that counts out the reamer. Once that chatter starts, it can be difficult to get it to cut smooth.
It shoots the same dirty or clean, inconsistent. A couple spots about halfway down the bore are loaded with copper.
Didn't check it for spotless cleanliness before getting the borecam so can't honestly answer that question.

 

[savagedasher]

The top picture looks like it needs a good cleaning. Larry

 

[Dusty Stevens]

Some just wont shoot. Best not to waste components. I have just as many if not more that wont shoot to my expectations.
One other thing to consider- one time about 10yrs ago hawkeye came out with a cheaper borescope. It came in a box less the $200 case. For about 2 years we had a rash of bad barrels. I admit i made my fair share of money off that. And with this new lyman bore cam its happening all over again.

 

[hogpatrol]

Thanks for the comments. Am wondering if the chatter would affect accuracy. After checking it more, I found some areas looked good, some ugly. I'm going to assume that the manufacturing process on this particular barrel was defective.

 

[Dusty Stevens]

The main thing chatter will do is hold copper

 

[spclark]

Am wondering if the chatter would affect accuracy.

My guess is: yes!

Ever drive fast down a washboarded gravel road then briefly take your hands off the wheel?

Think about the gas pressure behind each bullet as it passes down that bore. If the irregularities you see as 'chatter' left from rifling tooling is causing the bullet to chatter too, that vibration's got to contribute to weird ballistics once it leaves the muzzle. Maybe even irregular gas leakage from the variations in surface-to-surface dimensions.

 

[hogpatrol]

My guess is: yes!

Ever drive fast down a washboarded gravel road then briefly take your hands off the wheel?

Think about the gas pressure behind each bullet as it passes down that bore. If the irregularities you see as 'chatter' left from rifling tooling is causing the bullet to chatter too, that vibration's got to contribute to weird ballistics once it leaves the muzzle. Maybe even irregular gas leakage from the variations in surface-to-surface dimensions.

Good analogy on the washboard and inconsistent chrono numbers were the norm.

 

[Ggmac]

Hog patrol , read my post again , reamer marks after drilling , not rifling . A quality stainless barrel would be hand lapped to remove most . All barrels are drilled , lapped ,rifled , than maybe lapped .
Green mountain , ERShaw , are similar to production barrels and have reamer marks from drilling , not the reamer for chambering . I have no experience with hammer forged barrels but I would expect those to be drilled also

 

[hogpatrol]

Hog patrol , read my post again , reamer marks after drilling , not rifling . A quality stainless barrel would be hand lapped to remove most . All barrels are drilled , lapped ,rifled , than maybe lapped .
Green mountain , ERShaw , are similar to production barrels and have reamer marks from drilling , not the reamer for chambering . I have no experience with hammer forged barrels but I would expect those to be drilled also

The chatter marks are in the grooves so they wouldn't be cause by reaming. Check the first photo. The land is in the middle and the grooves top and bottom.

 

[Ggmac]

Again reamer Marks , after drilling . I understand what your saying , I had a hard time understanding the process . I've been using and rebarrel ing rifle for over 35 yrs and have retired , I've had many bore scopes over those years and have examined every kind of barrel Manufact process . A button barrel could have drilling reamer marks in in both , the button irons in the rifling , although you can usually see the marks once ironed in , they aren't usually a problem , the lands will of course see more wear , from cleaning , shooting etc.
With yours it's absolutly normal . A barrel with the marks like yours although confusing could shoot very good , unfortunately yours doesn't . A beautifully smooth barrel could shoot the same as yours .
It has not been asked but what make barrel , how many rounds thru it , have you ever used a bore lapping procedure ( shooting bullets with grit )
I'm not trying to be argumentative but your first look in to the bore is normal. If you were able to visit I have many new , used and worn out barrels I use to use to show clients the diff in stainless , CM , cut ,buttoned , hammer forged .
Check a few rifles that have an ERShaw or green mountain barrel .

 

[jsthntn247]

I have a Thompson Center Icon with chatter marks in the lands so bad you can easily see them with the naked eye, looks like rail road tracks. It copper fouls horribly but shoots as good as any factory gun I've ever had. Go figure.

 

[X Ring Accuracy]

FWIW, we have a bore scope. Use it occasionally. I have seen barrels that look like 5 miles of gravel road and shoot 1/4 MOA all day long. Seen match grade , lapped, air gauged barells that look great and shoot like sh&t. My point is, sometimes you get a turd. As some have said a bad chamber, that can be fixed but for barrels, it happens. Not so much anymore as everyone has good equipment, and few bad barrels come out anymore for the most part. Proof is always on the paper.

 

[watercam]

When in doubt, lap the barrel and see how it shoots. Patch on a slightly undersized bronze brush and 400 grit lapping compound works for me. Perhaps twenty passes to start and take a look. Many's the barrel I performed this method on and have had good success with more than half of them. You may not eliminate the chatter but you can certainly smooth it out.