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So what do you think about the inside of my my SK-19 barrel

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biohazardman

biohazardman

Member
Jul 3, 2019
5,451
260
Herriman, UT United States
Barrel was replaced several months back. I did not clean it as good as I thought? ;^) Pellets are spiraling bad. This is the leade the rest is clean.

Pellets don't appear to be damaged when I push them through with a cleaning rod. Is it enough to spiral all pellets at all speeds? I got the better part of the lead out although about ten percent of it is very stubborn and I am still werqing on it..

https://youtu.be/DLAD1JofW84

Dirty

https://youtu.be/kkNizstQQSI

Clean


 
I'm far from an expert and I can only tell you what I see in comparison to what I see in my barrels. To me the barrel looks pretty darned good. I see some lead but is it enough to cause any trouble? (I have no clue). What I do notice is some tooling marks in the barrel right at the end of the video which I assume is the chamber (or what would amount to a chamber). Do you think there is a diameter discrepency between the barrel and the pellet. I guess you could tell by how the pellet slides down the bore???
 
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For a comparison.

I just bought a real "target" pistol. Yeah, not at all inexpensive...but the barrel bore is like a mirror. Not a mark that I could find.

I know that this doesn't matter, but, I thought I was doing well with a couple of my other pistols. Standing at the same distance (30ft.) as my other pistol shooting, same stance, elbow steadied on the side of my arm, five rounds fully under a dime. Wow..!
 
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Pellets seem to slide in easy get a little tighter when they first engage the rifling then are quite easy to push through until they reach the choke. I thought the leade/chamber area looked a bit rough but was not sure. The rest of the barrel has no tooling marks to speak of.
Click to expand...

Yep and I have no clue as to what to expect or what's ideal.. Hopefully more people with more experience and knowledge will chime in. Im sure that there are barrels out there that look pretty average and shoot great and then there would be the opposite. Be nice if a fellow could tell by looking that's for sure. Some say you want a coating of lead. Now to me that just doesn't seem to make good sense. I;d think the cleaner and slicker the barrel was the better

Seems like with what you are experiencing some thing would be noticeable wrong. Hope you find it. 
 
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That "chamber" looks pretty rough! Either the edges of the reamer were dull and/or chipped the reamer was allowed to pack and chips were dragged over the edges. Not sure it would have much impact on accuracy though. I suspect the 'real' problem might have been "smearing" of the lands, in which case between your shooting and your cleaning it looks like any burrs that may have been present at the start of the rifling are now gone. I expect you to see better performance - looking forward to your range report!

GsT
 
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Bio,

You should try to get a replacement before anymore work. But any leading eventually causes more lead to solder itself up the bore, Dont be afraid to use WD40 and a bronze brush to help get all the lead you can (if the factory won’t give you a new tube.. Then use tight patches with JB borepaste to try to smooth those rough circular toolmarks some. Frankly that barrel shoould not have left the factory.
 
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GeneT

Yes I thought it looked pretty bad as well. There was so much lead build up I could not see if there were any burrs or not but with that kind of leading I would suspect there were. I can't get out to test it till Fri so I will post the results.



Therealld

This is the third barrel for the gun. Here is the first.



The second got trashed in shipment somehow. This one would not go on the gun so I sent it to AOA and they put it on. I thought it was shooting OK with exception of the all to regular fliers until I caught the spiraling one day. I did have to use the bronze brushes on it. Started with a well worn one but it did not get it all out so had to use a new tight fitting brush and it did pretty good. Thought about polishing it up with some 600grit sandpaper in the drill but haven't decided on that yet.



I will check and see how it shoots first and then if needed I will do another warranty replacement on it.
 
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Yeah that bore looks pretty rough. No wonder it’s leading up the barrel so easily.Them tooling marks are going to collect lead a lot quicker than the rest of the barrel. I would guess that was your problem all along.If it was Mine, I would polish that barrel but put more attention To the chamber area. Because without Smoothing them tooling marks down some, it’s just gonna keep on leading up real fast.
 
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Sir, that leaden has serious problems, Do you have a dremel type tool? Rubber fine abrasive bullet points for polishing do wonders for the leade, and the top of the lands are needing a good polish as well. Jason can tell all the ways to do it. I use fire lapping first, follow by soft structured 3m abrasives followed by jb bore paste and finally flitz polish. 

Good luck Sir!! 

Here is a pic o f a barrel ion a gun I am working of for the actual company that produces it. I found a barrel very similar to yours. Only much worse. Here ia a pic at 50 yards on the same target paper showing the before and after using my methods. 

It is still not a premium barrel by any stretch of the imagination, but much improved. It is only 50 yards. 20 shots each time. both from a clean barrel before leading in. It is now more accurate now that it has broken in. It will still hold an inch at 80 yards with cheap crosman hp's. Who would have thought. ( I don't usually shoot pellets, so it is all I had. 

Knife

DSC02730-1.1616667949.JPG

 
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Bio, don’t use 600 paper on flap-shaft in leade. I have had good luck with 0000 oiled steel wool wrapped around worn bronze brush but pushed in and out of the leade area to help eliminate circular tool marks ... I think its better to follow the boreline rather than spin the paper. That said, I do often use the flexible abrasive rods ground to slight taper and even 1000 grit wet or dry wrapped in a cone shape to do final polish but with barrel in lathe, spinning one way then the other for roughly equal times, checking often until most of a largish pellet can be pushed into the leade with one finger.

Then use the JB bore paste, first firelapping, then polish with patches on jag.
 
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Bio, don’t use 600 paper on flap-shaft in leade. I have had good luck with 0000 oiled steel wool wrapped around worn bronze brush but pushed in and out of the leade area to help eliminate circular tool marks ... I think its better to follow the boreline rather than spin the paper. That said, I do often use the flexible abrasive rods ground to slight taper and even 1000 grit wet or dry wrapped in a cone shape to do final polish but with barrel in lathe, spinning one way then the other for roughly equal times, checking often until most of a largish pellet can be pushed into the leade with one finger.

Then use the JB bore paste, first firelapping, then polish with patches on jag.
Click to expand...


Good advise for removing the burrs you've already removed, and a good first step to conditioning any factory barrel. It's very hard to tell from a photo, but I don't think the scoring shown in the video will buff out. However, it may be of no consequence at this point, as there are no visible burrs on the lands. 

I'm duffing it here - my expertise is in the powder-burner world, but I'm guessing those rings don't hurt accuracy much, though they'll certainly lead to leading. They look deep enough that polishing them out might decrease accuracy. In the PB world they'd create an extraction problem for sure, but I'm not as convinced that they're a real issue here. Smearing the lands (which I suspect, from the general state of the machining) would definitely destroy accuracy, and Therealld's advise is spot on for addressing that.

GsT
 
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The circular scoring in the lead-in looks particularly bad and I would expect it to continue to scrape lead flakes off of each pellet or slug. I would call that a manufacturing defect. I don't believe that any upper echelon brand barrel should ever have tool marks like that. As a previous poster pointed out, it looks like the tapered reamer was either damaged or fouled with chips that cut circumferential grooves.
 
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