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Thread: Slugging new barrel blanks?

  1. #1
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    Slugging new barrel blanks?

    A good friend and local gunshop owner has recently started chambering barrels. He has a machinists background and also attended a well known school for barrel work. He has chambered a couple of barrels for me and his work is meticulous. I think he is capable of doing excellent work and is interested in all the nuances. Yesterday he told me that it has been strongly recommended to him that he slug all new blanks that customers bring to him for chambering. This would be to avoid problems arising from "bad barrels" and him being blamed for doing poor work, when in fact, it was an inferior blank. I have been playing the benchrest game for going on twenty years and have had numerous barrels chambered. So far, maybe I've been lucky, but I've never had a really "bad barrel". In fact, most have been excellent, with only a few even mediocre. I'm certain that none of those who have chambered my barrels have slugged them. So, my questions are, do most smiths habitually slug new blanks? Do those of you who do your own barrel work slug your blanks? Considering adding the recommended charge of $100 for slugging to the cost of chambering, threading both the tenon and muzzle end for a tuner, is this a cost effective idea for the shooter or the gunsmith?

    Rick
    Last edited by Greyfox; 04-22-2018 at 01:44 PM.

  2. #2
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    Slugging a blank is much more common if the barrel will be used with lead bullets such as 22LR. A lead bullet gun doesn't have the pressure to deal with groove diameter variation like a CF. That small bore variation may affect the accuracy with lead bullets.

  3. #3
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    IMHO it is just another excuse to charge the customer more money. I wonder who "recommended" the slugging. I'm no pro, but I have used several barrels from Shilen and Krieger in my own rifles. I have never slugged one, but I have inspected all with a bore scope. All have been completely smooth and perfectly finished. I don't see how one of their finished barrels could have a significant variation in the bore or groove dia. because of the manuf. and inspection techniques they use and the fact that they hand lap every barrel before shipping. Maybe cheaper barrels made from less than highest quality blanks can have problems, but I don't use them.

    RWO

  4. #4
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    A well known smith showed me how a Krieger barrel bore I had was larger for the last 2 inches of the muzzle. You could feel it with a lead slug. Jackie on here recently had to cut off and recrown a barrel and it improved. Maybe slugging would have caught that. Who knows.

  5. #5
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    Quote Originally Posted by RWO View Post
    IMHO it is just another excuse to charge the customer more money. I wonder who "recommended" the slugging. I'm no pro, but I have used several barrels from Shilen and Krieger in my own rifles. I have never slugged one, but I have inspected all with a bore scope. All have been completely smooth and perfectly finished. I don't see how one of their finished barrels could have a significant variation in the bore or groove dia. because of the manuf. and inspection techniques they use and the fact that they hand lap every barrel before shipping. Maybe cheaper barrels made from less than highest quality blanks can have problems, but I don't use them.

    RWO
    I am a rimfire shooter and I do my my own barrel work and wouldn't even think of setting up a blank without slugging it first. I use good hand lapped blanks from shilen, mueller, benchmark, krieger, and the rest and someone who doesn't slug in the rimfire game is letting luck control how their barrel will shoot. May not be the case in centerfire because of the preasure increase but I am not flying blind on the few centerfire rifle barrels I do either. May not be much of an advantage on the centerfire but I am all about getting every crumb I believe is there.

    While I would be comfortable in doing a barrel just off of the feel of a slug, I like having a borescope to make sure there is no funny stuff going on in the section of usable barrel I want. On the contrary I would not feel comfortable in just using the borescope to evaluate a new blank with no slugging. I know there are good centerfire barrels created every day that aren't slugged but I just don't feel that lucky.

    As far as the charge, I don't know how well that will go over. Once a person gets comfortable with doing it, a pretty good idea can be made of what's going on inside in about 15 minutes. Little more time for someone looking for benchrest accuracy but not substantially more.

    Tad

  6. #6
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    Quote Originally Posted by Tad.E View Post
    I am a rimfire shooter and I do my my own barrel work and wouldn't even think of setting up a blank without slugging it first. I use good hand lapped blanks from shilen, mueller, benchmark, krieger, and the rest and someone who doesn't slug in the rimfire game is letting luck control how their barrel will shoot. May not be the case in centerfire because of the preasure increase but I am not flying blind on the few centerfire rifle barrels I do either. May not be much of an advantage on the centerfire but I am all about getting every crumb I believe is there.

    While I would be comfortable in doing a barrel just off of the feel of a slug, I like having a borescope to make sure there is no funny stuff going on in the section of usable barrel I want. On the contrary I would not feel comfortable in just using the borescope to evaluate a new blank with no slugging. I know there are good centerfire barrels created every day that aren't slugged but I just don't feel that lucky.

    As far as the charge, I don't know how well that will go over. Once a person gets comfortable with doing it, a pretty good idea can be made of what's going on inside in about 15 minutes. Little more time for someone looking for benchrest accuracy but not substantially more.

    Tad
    Hi- What is the procedure for properly slugging a barrel? How do you get the slug to swell up sufficiently? If the barrel has choke do you slug it from both the breech end and also the muzzle end and only then drive the slugs to say, the middle of the barrel in each case? Also, is it possible to slug a gain-twist barrel?

    Sorry for all the questions but I'm sure there are right and not so right ways of doing this!

  7. #7
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    Hi wall check your pm's.

    Tad

  8. #8
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    Shilen requires you cut off at least I" on both ends of a blank. Supposedly this is because that area is enlarged from the finishing lap's travel being reversed at each end. They claim to air gauge all bores, so that should reveal any other changes in dia.

    I recently received a 22 cal CF blank from Krieger . The bore was specified to be 0.218. A 0.2180 gauge pin would go in both ends very easily for about 1.0" and then the fit got very snug over the next 0.5" I was planning to cut both ends about 1.5" anyway, so went ahead and did so. After cutting and deburring, the pin was a snug fit in both ends. So, I am forced to conclude that lap reversal caused bore enlargement, even though Krieger doesn't mention it their literature that I have seen.

    RWO

  9. #9
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    If you do slug a barrel, (centerfire in this case),and find some precieved tight or loose spots, what do you do then?

  10. #10
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    Cheap insurance on a barrel blank to make sure any lapping was done correctly.

    It is very hard to put metal back into a bore after removing it.

  11. #11
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    I never put a tool to a new Benchrest barrel without slugging it first. Charging $100 extra to slug a barrel is a rip-off!

    The last barrel I returned had a oversized portion about 6 from the muzzle and it was about 6 long. The person who caused this oversized area was apparently trying to lap out an inclusion. Bore lapping should ALWAYS be the first step in chambering a Benchrest barrel!!

    ..

  12. #12
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    Sent you a reply back!

    Quote Originally Posted by Tad.E View Post
    Hi wall check your pm's.

    Tad

  13. #13
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    Quote Originally Posted by FBecigneul View Post
    What do you do if a new barrel doesn't gage well?
    Send it back?
    The usual reply.........."It's within manufacturing tolerances".

    The manufacturer might agree to exchange it, and then simply stick the returned blank back in inventory.

  14. #14
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    Quote Originally Posted by FBecigneul View Post
    What do you do if a new barrel doesn't gage well?
    Send it back?
    Out of 60+ barrels Ive slugged Ive only found 3 with faults. None of these were refused returns.

    Slugging is better to determine faults than air gaging, IMO. Air gaging works great before the rifling is cut but not afterwards.


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  15. #15
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    Quote Originally Posted by jackie schmidt View Post
    The usual reply.........."It's within manufacturing tolerances".

    The manufacturer might agree to exchange it, and then simply stick the returned blank back in inventory.

    How many barrels have you sent back and gotten that reply. Or is that just heresay. If you really believe your barrel maker is selling you barrels sent back then all the more reason to look into slugging your own barrels.

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