Slugging new barrel blanks?

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Greyfox

Active member
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
 
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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.
 
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
 
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.
 
RWO said:
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
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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
 
Tad.E said:
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
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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!
 
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
 
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.
 
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!!

..
 
FBecigneul said:
What do you do if a new barrel doesn't gage well?
Send it back?
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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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jackie schmidt said:
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.
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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.
 
I've already said that I don't have a dog in this fight and just asked for research reasons. That beings said, I'm pretty skeptical about claims that tight and loose spots can be felt by a human arm pushing a dead soft lead slug much less a 22lr bullet or buckshot. The air gauges are capable of detecting extremely small changes and I can't see a quality barrel maker sending out barrels that they know are inferior. As the slug obderates and lubricant gets thin I can see the feel being different, but not due to changes in the bore size. I can see the maker being willing to take barrels back and replacing rather than making a customer mad. I suspect they inspect a returned barrel and put it back on the shelf. I am aware of one instance where a barrel was returned by a person who didn't even purchase it directly from the maker. After slugging he insisted that is was "bad". The maker swapped it out and inspected on return finding it perfect. I suspect this is often the case. I am going to say that I will not allow anyone to slug a hand lapped custom barrel of mine, much less pay them for it. But that's just me and what do I know?

Rick
 
sdean said:
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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Some 20 years ago, I had a barrel from a well known supplier that was copperring bad. It would not shoot.

I called the supplier, and his answer was that they made their barrels to exacting standards, so I was doing something wrong. I never bought another barrel from them.

I have only sent one Krieger back in 20 years. It had a spot about 2/3 the way up in the chamber. I could actually feel it. It was an inclusion in the steel. I sent it back, they agreed and emmediatly sent me a new blank.

I haven't slugged a barrel in years. I just chamber them up and shoot them.
 
Greyfox said:
That beings said, I'm pretty skeptical about claims that tight and loose spots can be felt by a human arm pushing a dead soft lead slug much less a 22lr bullet or buckshot.
Rick
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And an "air gauge" is nothing more than an airline with a gauge on it........ pushing a slug

it ain't magic. Especially since't air molecules are HUGE and easy to trap. Maybe "helium gauging" is the answer.

I'm pretty skeptical that you've ever actually been up close and personal with either method :)

Especially since you mention "lubricants"....??
 
alinwa said:
And an "air gauge" is nothing more than an airline with a gauge on it........ pushing a slug

it ain't magic. Especially since't air molecules are HUGE and easy to trap. Maybe "helium gauging" is the answer.

I'm pretty skeptical that you've ever actually been up close and personal with either method :)

Especially since you mention "lubricants"....??
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You are correct that I have never have and probably never will take part in such an exercise. My information comes directly from a barrel maker. As with information I've received directly from you, I believe him and trust his veracity.

Rick
 
Greyfox said:
I've already said that I don't have a dog in this fight and just asked for research reasons. That beings said, I'm pretty skeptical about claims that tight and loose spots can be felt by a human arm pushing a dead soft lead slug much less a 22lr bullet or buckshot. The air gauges are capable of detecting extremely small changes and I can't see a quality barrel maker sending out barrels that they know are inferior. As the slug obderates and lubricant gets thin I can see the feel being different, but not due to changes in the bore size. I can see the maker being willing to take barrels back and replacing rather than making a customer mad. I suspect they inspect a returned barrel and put it back on the shelf. I am aware of one instance where a barrel was returned by a person who didn't even purchase it directly from the maker. After slugging he insisted that is was "bad". The maker swapped it out and inspected on return finding it perfect. I suspect this is often the case. I am going to say that I will not allow anyone to slug a hand lapped custom barrel of mine, much less pay them for it. But that's just me and what do I know?

Rick
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Rick, every competitive shooter I know will tell you they can feel variations in the bore of a rifle they're cleaning with a rod and a patch. I know I can! I can also see variations in the lands with a bore scope on many barrels I own and I'm not superman. Most of these barrels shoot fine, some with obvious flaws will outshoot some with no apparent flaws, go figure. I don't think the top shelf barrel companies run around lying or bullting us about the quality they try to attain but sometimes mistakes happen and they get missed. Never forget they're in business and have to make a profit like all the rest of the businesses out there.
 
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