Damaged Bore!!??

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Shumba, Oct 17, 2008.

  1. Shumba

    Shumba Well-Known Member

    Messages:
    159
    Joined:
    Aug 14, 2008
    I just returned from Namibia from a plainsgame hunt. I cleaned my rifles last night and found something disturbing.

    A little background info on one of the rifles. The 338 RUM in question here is a custom made rifle, with a Krieger barrel. I had the rifle made specifically for this hunt. The rifle is a .5 moa rifle with good bullets, and has only had about 200 rounds down the barrel.

    Here is the problem. When patching out the bore after brushing, I found a loose spot in the bore. The spot seems to be between .5 and 1 inch roughly 3-4" from the muzzle. When pushing the patch down the bore the patch is tight then the rod slips forward the above distance then feels like it engages the lands again. I used two different cleaning rods to make shure it was not some issue with the ball bearings in the handle making it feel like a loose spot...nope its in the bore.

    I have not shot the rifle at a target since the first day of the hunt. What is the oppinion here? What could have caused this? I only fired this rifle 5 time on the hunt and never had an extraction problem which I would think would be caused if there was some sort of obstruction in the barrel that could have caused this. I am baffled, I wish I had a bore scope. I have also Mic'd the barrel around the loose spot looking for a bulge...nothing.

    I Have ran no less than 8 patches down the bore of this rilfe every 20 rounds for 200 rounds over the last 4 months, point is I know what the bore feels like. The loose spot might as well be a hole in the side of the barrel.

    Any Ideas, obviously the barrel is ruined I am just curious how this could have happened.
     
  2. Boss Hoss

    Boss Hoss Well-Known Member

    Messages:
    1,843
    Joined:
    Nov 10, 2005
    Bore Scope it---then you will know.. PM me and I will do it for you......
     

  3. Boss Hoss

    Boss Hoss Well-Known Member

    Messages:
    1,843
    Joined:
    Nov 10, 2005
    Bore Scope it---then you will know.. Am gong to the ranch tomorrow all day to change the anti freeze on the John Deere but will be here all day today leaving about 6 tomorow and back on Sat afternoon.

    A Krieger with a problem!!!!! I have got to see this!!
     
  4. dbhostler

    dbhostler Well-Known Member

    Messages:
    837
    Joined:
    Sep 12, 2002
    Recommend you contact Krieger and do as instructed.
    db
     
  5. Boss Hoss

    Boss Hoss Well-Known Member

    Messages:
    1,843
    Joined:
    Nov 10, 2005
    After much discussion and an examination -- bore obstruction. Calling Krieger will do no good.
     
  6. phorwath

    phorwath Well-Known Member

    Messages:
    4,896
    Joined:
    Apr 4, 2005
    Ouch! That's gotta hurt. Thanks for the follow-up.
     
  7. Shumba

    Shumba Well-Known Member

    Messages:
    159
    Joined:
    Aug 14, 2008
    Update
    . I had a friend look at the bore friday with a borescope and it was obvious that the lands had been flattened in the areea of the loose spot, although only on one side of the barrel, there was also a gouge full of copper in one of the grooves.

    I decided to shoot the rifle before I sent it back to the smith (Gordy Gritters) to haved a new barrel put on. I shot the rifle today and before the damage the rifle shot a consistent 3 tenths three shot group with the load I took to africa. Today I shot the rifle and it shot just as well as it did before. I would have bet anyone a new barrel that it would not shoot at all. It is amazing that a rifle can shoot with this kind of damage to the bore. You can actually push the patch into the loose spot and pust it back and fourth without it makning the cleaning rod turn, like it is not even engaged in the lands...
    [​IMG]
    Here is the group shot today. The shot on the right is the fouler or cold bore shot and the three shot group is the load I shot in Africa. The group size is the same as before the damage. I do not know how the barel can shoot with this kind of damage to the bore. I actually saw the flattened lands with my own eyes in the bore scope.

    I am very happy with the results I just do not understand how the rifle can shoot just as well with the damage to the bore.......\
     
  8. dogdinger

    dogdinger Writers Guild

    Messages:
    697
    Joined:
    Dec 1, 2007
    with the problem so close to the end of the barrel , why not just trim and inch off the end?
     
  9. Boss Hoss

    Boss Hoss Well-Known Member

    Messages:
    1,843
    Joined:
    Nov 10, 2005
    Almost 4 inches would not be good for the big RUM.



    The tractor took us 6 hours yesterday and Speedy called me while we were working on it so I have not talked to him yet is why you did not hear from me. That group just shocks the devil out of me would love to shoot it across the Chrono to check the velocities!!
     
  10. Shumba

    Shumba Well-Known Member

    Messages:
    159
    Joined:
    Aug 14, 2008

    If it was that close it would make sense. The damage is actually around 4" from the muzzle.

    David,
    I plant to try and do chrono it today if I get the chance. You would also think that the loose spot would let the bullet slip forward and when it hits the tight portion of the bore would cause a spike in the preassure curve, possibly causing preassure signs on the brass, but this is not the case. This load is right at max, so any it wouldnt take much preassure increase to show signs but there are none on the brass from yesterday. No visible signs or head expansion????:confused:

    I am obviously glad it still shoots, although I know I am going to get sick every time I clean this barrel, and feel that spot. I guess its like a smoking hot girl with a big wart on her chest. Still a hot girl that functions but you never quit thinking about that wart:D
     
  11. Varminator 911

    Varminator 911 Well-Known Member

    Messages:
    337
    Joined:
    Dec 7, 2007
    By the time the bullet gets that far down the barrel the pressure has fallen dramatically. So there isn't going to be a pressure spike above peak. If that was going to happen, it would have been when the damage occured. I'm also not surprised that it shoots like it did. Had you damaged the rifling right at the muzzle, then it likely won't shoot as well.
     
  12. phorwath

    phorwath Well-Known Member

    Messages:
    4,896
    Joined:
    Apr 4, 2005
    If it shoots like that, I'll buy it from you at a discount for that damaged bore... :D Kidding. Look's like it's still a tack driver to me.

    If it'll shoot those groups without high Extreme Spreads or SDs, I'd just keep shooting it until she's shot out.
     
  13. ovastafford

    ovastafford Well-Known Member

    Messages:
    938
    Joined:
    Oct 23, 2009
    I saw how old this thread is but I think I may have the same problem. I finally got a bore brush for my .264 and I was cleaning it and I felt a loose spot. Its at about the middle of the barrel and I can only feel it with brush and not the patches and only feel it with the brush on push stroke and not the back. Its a sendero and there is probably around a hundred rounds through the barrel. I shot it today and it grouped great at 100 around half moa but at 200 and 300 it was quite erratic with groups around 1-2 moa. I dont have a bore scope, any ideas? Thanks
     
  14. Fitch

    Fitch Well-Known Member

    Messages:
    478
    Joined:
    Aug 5, 2009
    Borescope is good. Slugging it is good too. Doing both is best. Since you don't have access to a borescope try slugging it. You can learn a lot by slugging a barrel. Gordy Gritters has a section on slugging the bore in his video about diagnosing rifle accuracy problems. The video has a lot of information in it.

    Fitch