burr in barrel
Just had a rifle in the shop this afternoon. About 3 to 4 inches in front of the chamber throat, one of the rifleing lands appears to be lifted up. This is visible to the the naked eye. It appears as a black spot on the land, and is visible frome the breech end or the muzzle. This barrel has had only 85 round through it. Any input would be welcome. Thanks
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What kind of rifle? What caliber? Do you think maybe it was cleaned from the muzzle using a stainless rod? How high is the swell (and long) and does it look as though it is shaped like a ramp; gradual rise to a flat drop off? If so I would point to the stainless steel rod without a good same diameter brass jag screwed in place. I guess it could be a defect in the metallurgy but if it is a decent quality rifle from a well known manufacturer I would rather tend to doubt it. Did the customer not really check the barrel out before shooting it to insure his break-in was going to be done correctly; if not that was likely a pretty serious omission in standard practice. I always try to check this out so I have a good base line of visual data to avoid doing harm to the barrel life right out of the box. Please repost with an answere to some of these questions so I might be able to provide a little more help.
"When I cease learning...I'm dead"
"Power corrupts...Absolute power corrupts absolutely"
"History is written by winners"0 -
And what did the shop tell you?
If it is a new rifle of any quality at all and not cleaning damage contact the mfg. as it may be a warranty issue that could be voided if you or non-authorized shop try and correct.
If it is an older rifle, or not covered by a warranty for some other reason then you have the choice of shop or self, and you may want to try and take care of it. If so my suggestion is to take a worn brush, wrap it with a cleaning patch and coat that patch with valve polishing compound (not valve grinding) and give the bore 10-12 strokes ... change patches and repeat, then run cleaning patch through and check the bore to see if the situation persists, if it does but is improving, repeat the polishing process until you've smoothed the area out.
Don't confine your polishing to just the area of the "spot" run the compound coated patch the full length is a smooth steady stroke.
Also you may want to use a nylon or brass brush in your cleaning step as this will help remove anything down in the rifling grooves.
Valve polishing compound should be available at any autoparts store and sells for $3-4 a tube. Again polishing NOT grinding compound.
If you only have time to do two things so-so, or one thing well ... do the one thing!0 -
Hi. The caliber is 22-250 AI. barrel stainless steel, from a well know barrel maker. I did the barrel job on a short montana rifleman action. Cleaned barrel from breech end. Test fired to check the chamber. Everything looked OK. The ouner is an experianced rifleman/shooter, and handloader. The spot looks like a dark spot in the rifleing land, visible from breech and muzzle. Does not appear to be raised and I canno't feel it with a tight patch, or bore gage. It is a puzzle to me. I have never in 30 some years of riflesmithing seen anything like this. 0 -
Try the maker. During the rifling operation the rifling button may have seized and galled the stainless barrel in a spot due to a momentary lack of lubrication. The galled area would be rough and may have picked up copper from the bullets. A borescope would give a good view of the site.
If you're lucky the defect can be improved by lapping.
Try to lean on the manufacturer to make good on the barrel before spending any money on it.
I assume you have tried strong copper removing cleaners.0 -
Thanks, I will contact the barrel maker, and also ask the ouner if he tried copper out. Thanks again 0 -
V35 has a great point. Also,..you may wish to continue on a break-in proceedure and see what developes. Most throats are tapered and will often look dark,..even when only fired a few times. This si what is reffered to as the verticle prcession of the rifling/throat into the bore. Even the BEST match grade barrels,..when fist chambered will need quite a few rounds fired to "round off" of the rfiling at the throat. This is simply wearing the sharp edges of the throat off in the first 20-40rnds. Yoy may be only witnessing the stripping of copper from the jacket of the bullet as the new throat is being smoothed out. I would wait ~60 rnds (while adhearing to a strict 1 shot clean then 3 shot clean method) and then take a look at the bore/throat again. Aftermarket reamers are far tighter and sharper than factory reamers. That leads to the rifling being at a very sharp opposing angle to the chamber. This will most often wear down in around the first 30-40rnds. You may very well have an exceptionally well cut barrel. I have had barrels take over 100rnds to settle in and stop stripping copper from the bullets.
why chase the game when the bullet can get em from here?....
Got Balistics?0 -
V35 has a great point. Also,..you may wish to continue on a break-in proceedure and see what developes. Most throats are tapered and will often look dark,..even when only fired a few times. This si what is reffered to as the verticle prcession of the rifling/throat into the bore. Even the BEST match grade barrels,..when fist chambered will need quite a few rounds fired to "round off" of the rfiling at the throat. This is simply wearing the sharp edges of the throat off in the first 20-40rnds. Yoy may be only witnessing the stripping of copper from the jacket of the bullet as the new throat is being smoothed out. I would wait ~60 rnds (while adhearing to a strict 1 shot clean then 3 shot clean method) and then take a look at the bore/throat again. Aftermarket reamers are far tighter and sharper than factory reamers. That leads to the rifling being at a very sharp opposing angle to the chamber. This will most often wear down in around the first 30-40rnds. You may very well have an exceptionally well cut barrel. I have had barrels take over 100rnds to settle in and stop stripping copper from the bullets.
why chase the game when the bullet can get em from here?....
Got Balistics?0 -
Seems to me these gentlemen are on the right tack here but failing all the good advice I am beginning to think poor chrstaline structure in that spot in the rifling...this is really not too likely especially with a good stainless barrel but I cannot help but wonder? Spot copper build-up that near the troat is a likely thing but one would think with todays concentricity in barrel manufacture and rifling that it would build on all the lands at least a bit, not just the one. The one gentleman has a really good point in that I think I would lean on the barrel maker a bit to see if they weren't willing to either come up with an answere or make good on the barrel with a new one. I'm sure your customer is a bit bent with the whole deal so good luck and hang in there as there has to be a logical answere here!
"When I cease learning...I'm dead"
"Power corrupts...Absolute power corrupts absolutely"
"History is written by winners"0
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