Need opinions - odd barrel marks inside new P938 barrel

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barrybenson1776

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Last week, I bought a brand new P938 SAS model. It has a born on date of 03/08/16, so it's very new. I also own a P226 that I've had for over 15 years.

I have not shot or used it at all. When I went to clean it, I inspected the barrel, and I immediately noticed odd ripple marks in the grooves in the inside of the barrel that are present throughout the entire barrel. The lands seem normal and smooth, aside from what I hope is just copper fouling.

I called Sig customer service, exchanged emails and pictures, and they said it's normal. The rep stated that he checked some P238 barrels, and they were like this too. He didn't mention if he checked P938 barrels. He also said it is most likely from the broaching process of rifling the barrels.

Can anyone take a look at this and let me know if their P938 barrel is like this?

It seems really odd to me, and I have not seen this before. I'm especially concerned because of the very high price of this gun. I'm really curious to see if anyone else has these. If it will not hurt anything, then I'll just live with it. If it turns out to affect accuracy or fouling, then I'll insist on a replacement.

Also, can replacement barrels just be swapped out, or do they need some type of fitting?

Thanks for your time!!

Please let me know what you think. See the attached picture.
 

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I agree with the rep that I've seen similar marks from broaching of metal parts. I'm not sure where you bought the pistol, but one idea would be to see if they themselves have other P938s available that you can spot check.

I have a friend that works at SIG and he's talked with me before about how the broach itself eventually becomes worn and starts to tear metal as opposed to cutting it. That's why the broaches have to be replaced periodically. It may be that the broach here was getting closer to the end of its life (although these marks are very concentric so I don't know if that's the case here).

Still as long as the lands and grooves are sharp you should be fine. If you can't find someone to spot check it then I'd shoot it and observe for problems. These are production pistols so the replacement barrels are just drop in.
 
The rep did say, and others on another site, to try it out at the range and see how it goes. I'll definitely do that as soon as I can get there.

I'm trying to get an idea of what's normal vs. warranty claim. I don't want to accept something that's wrong but I don't want to belabor a non-issue.
 
The first job I had in a shop was operating a broach. Not rifling and I wasn't on that job for long, but I have a little experience.

I saw similar marks quite often. As previously stated it more often than not means the broach is worn and tearing its way through instead of cutting. The broaching bar will shake and jump instead of cutting smoothly.
For a keyhole or spine cutting gang-broach it can also mean one or more of the teeth have chipped. That results in the subsequent tooth cutting double. I'm not sure that applies to a rifle broach. It can also mean the broach was run too fast(which for many dedicated broaches means the broaching tool was not designed correctly). I ran into that when using the incorrect bar on parts.

I don't think it is inherently any bigger problem than tooling marks anywhere else in a pistol. The marks are probably less than .0005" deep. I would shoot it a bit and see what happens. My guess is there is no negative effects an it smooths out pretty quickly. Fowling/leading might be high at first, but I would be surprised if that is even noticeable.

I've seen tools for cutting rifling, but I have never used one.
I'm a little disappointed Sig uses this method. It is an economy method.
 
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Well, I can't get a refund because all gun sales are final at the store I bought it from.
I can do the whole warranty replacement thing through Sig though.

I was going to shoot it and see how it goes.

I'd be happier if I had a replacement and no issues, but we'll see. I wrote this thread to have a discussion about this and see if others have this, have seen it before, or have experience in this area.

So far, I'm getting great info and I greatly appreciate it!
 
I have seen that before... but only on Ruger stainless 22lr barrels.

One in an SR22, and another in a 22/45.


It did not affect accuracy to any noticeable degree, as the 22/45 is very accurate.


One thing it did do... Or more accurately, I suspect it does. Is cause the barrel to lead easier.

Only a problem when shooting non-plated 22, and maybe not a problem with well lubed non-plated 22, but most domestic stuff is not lubed well, as its usually the cheap stuff.

Now after putting about 1000rds of plated 22 through the SR22, the leading issue is nearly eliminated. Testing this on the 22/45 right now. I suspect the barrel is "breaking in" or basically, its being lapped through firing.


This is not likely to be an issue with a centerfire pistol, as most ammunition is jacketed.
 
Thanks marine, that's good to hear. Like I said earlier, since I haven't even used it yet, I think indeed to get to the range, get familiar with the gun, and check the accuracy. I hope it works fine.

Anyone have a P938 that could also check theirs?

Thanks again for the info.
 
I've seen tools for cutting rifling, but I have never used one.
I'm a little disappointed Sig uses this method. It is an economy method.
Click to expand...

I'm curious, economy as opposed to what? The true economy method for large scale operation is hammer forging. It involves a large up front cost that pays off over time. Any of the custom barrel makers I'm aware of typically use cut or button rifling.

http://dailycaller.com/2014/04/21/explained-the-three-types-of-custom-rifle-barrels/

http://pistolsmith.com/pistolsmiths/1514-what-broached-cut-rifling.html
 
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I've seen that before in rifling from various makers and it has no practical effect on the accuracy of a locked breech recoil-operated handgun.

Now, if that was a picture of a precision rifle barrel, then you might have a basis for a complaint.

Go shoot your new gun. It's fine and it's going to shoot just fine. ;)
 
I just took my 938 out to the back yard and ran a hundred rounds through it into little tiny groups and decided if it has marks in the barrel they must be doing the right thing to stabilize the bullet. Don't worry about the small stuff the pistol is a really great shooter, low recoil, accurate and extremely reliable--- what more can we want?
 
I'm curious, economy as opposed to what? The true economy method for large scale operation is hammer forging. It involves a large up front cost that pays off over time. Any of the custom barrel makers I'm aware of typically use cut or button rifling.
Click to expand...
I meant economy like "economy car" not economy of scales. The unit cost of a hammer forged barrel maybe lower in the long run, but the up front cost is a large risky investment for companies.
I prefer a hammer forged polygonal rifling barrel for pistols. The two modern semi-auto pistols I currently own, a Kahr and a Glock, have them; and I am very happy with the results, especially in the Kahr. Well, Hipoints have button rifling, and I may have one or two of those tucked away. The rifling isn't why I kept the Glock and Kahr, actually the Glock has an LW conversion that is traditionally cut(I wish it was polygonal), but it is part of the well thought out and designed package made with the consumers satisfaction in mind(IMO).
https://www.usconcealedcarry.com/barrels-and-bullets-conventional-versus-polygonal-rifling/
I was never impressed with the results of the broach I operated or even the aero parts I later worked with that had been broached. Regularly things like the marks in OPs barrel. Functionally fine, but a Sig 938 isn't a Hipoint.
If it were my gun I would probably run my 400 round standard break-in for a carry gun and hope the marks were gone. In this case being sure they were all jacketed bullets. The marks would probably be gone. If not I might run patches with flitz down the barrel, or at least post here asking what the effects would be.

I know many who reload and shoot lead or even cast lead prefer traditional rifling.
 
If those marks wear off with only 400 rounds, THEN I would contact the manufacturer. Not about the marks though--to complain about a soft barrel!

I've got a revolver that looked like the OP's barrel when new, and after several thousand rounds of full power jacketed .357Mag, I can still see traces of the marks.
 
"gone" may not have been the best choice of words. I would expect a profilometer to measure the surface as considerably smoother after 400 rounds. The increased friction at the high points will increase wear considerably over that normally found in a barrel. Just as lapping quickly removes riflings sharp corners during break in. My guess is one could take a stylus held lightly in their hand and feel the roughness in that barrel right after it was cut. After 400 rounds I would be surprised if that still holds true. Even on hardened super duplex, marks like that wear down pretty quickly. The ridges are only a few ten-thousandths above the valleys. They are sharp edges that are not supported.
https://en.wikipedia.org/wiki/Surface_finish

I'm sure a red 3m abrasive pad would do the trick in 2-3 passes
 
I've seen tools for cutting rifling, but I have never used one.
I'm a little disappointed Sig uses this method. It is an economy method.
Click to expand...

NOT TRUE. You may be confusing a broach with a button rifling tool.

Broaching tools and broaching machines are incredibly expensive. The broach has to be custom designed for the size of the barrel (both caliber and barrel length), and twist rate. Broaches are progressive cutting tools that need hundreds of cutters, chip relief / collection spaces, and oil lubrication ports.

This all has to be designed into the tool, and then the tool has to be made and finally sharpened.

That is hardly an "economy method."

Then when dull, the broach has to be sharpened - a whole task in itself that takes a specialized tool sharpening machine with multiple fixtures to hold the broach as it's sharpened.

Again, hardly an "economy method."

Colt used to broach all of their pistol barrels. The broach for a 5-inch, 1911 barrel was about 4-feet long to give you an idea of the size of the cutting tool.

The economy method is hammer forging. Sounds really cool and must be super great because of the word "forging."

In fact, the machine is expensive, the mandrel put into the barrel around which the barrel is hammered formed is relatively inexpensive compared to a broach, and doesn't have to be sharpened - you just throw it away and put a new mandrel in the machine.

If you can afford the machine, and you're doing a lot of barrels and want the lowest production cost - hammer forging.
 
I believe Lothar-Walthar is making most of the hammer forged barrels, not the individual companies. It would be interesting to know at what price they are buying the barrels.
Nevertheless, cold-hammer forged barrels with polygonal rifling are more durable, stronger, easier to clean, and retain their accuracy much longer than any other barrel.
Click to expand...
Does anyone disagree with that excerpt from the article I linked previously? And what are the disadvantages? Shooting lead without cleaning regularly MIGHT cause a barrel constriction and reduce accuracy. I've not seen any claims of there being a real problem and I am sure some yahoo has sent lots of non-jacketed lead down an HK without cleaning. Any others?

As for the complexities of manufacturing a broaching bar, I am well aware. If a person were using pen and paper, stone and file, to complete those operations, I might agree. The broach is designed once on using CAD/CAM. A CNC grinder then does most of the work. It isn't any more complicated or mysterious than a custom end-mill. The night shift guy used to break the bars regularly where I ran a broach. Gave me a bit of exposure to what went into a new one.
 
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Many thanks to all who have replied. I'm learning a lot, and it's an interesting discussion.

After I go to the range and go though my own "get familiar with this new gun/break in" process, I'll let you know how it went.

Plus, I plan to check out a few at some local gun shops to see if those have these markings too.
 
Again, many of the custom barrel makers use cut or button barrels because they can't afford the hammer forging setup. I have never heard anyone claim nor seen proof that cut or button barrels can't be quality (the KKM barrel I have shoots notably better off a bench than my stock Glock barrel because of how much tighter the fit is, despite it being a drop in; rifling to me is less important than overall fit). In fact barrel failures in general are pretty rare these days.

Now I cut my teeth on shooting HKs and I carry Glocks (with the stock barrels) so I have nothing against cold hammer forging or polygonal rifling. But I wouldn't hold it against a company not going that route. SIG has always used traditional rifling to my knowledge and they have a good reputation. By the time you've shot out a traditional barrel you'll have spent so much on ammo that you could have bought a new pistol many times over.
 
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Smith & Wesson used to broach revolver barrels. Single cutter was too slow and button not well suited to asymmetric cross sections like a barrel with a top rib and underlug. But then they lapped the barrel after broaching for a nice smooth finish. I don't know what they are doing for their standard calibers now. I understand the monster magnums are ECM rifled. With a gain twist to boot.

Does anybody make a Glock type wavy "polygonal" barrel of true Match WINNING Grade, rifle or pistol?

I am sure there are some target rifle barrels made by hammer forge, but nobody who can afford the machinery tries for benchrest precision.
 
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