View Full Version : Off-center Bore?

July 14, 2007, 22:26
Hi all,
I just received my new barrel for my carbine build on Friday from DSA. This is one of DSA's new production 16.25" Carbine Chrome Moly Barrels. I test fit it onto my DSA reciever, and it hand-timed almost perfectly, between 10:30 and 11:00. BUT, I then test fit the short Steyr flash hider and noticed something a little troubling. The bore seems to be misaligned.

Here is the naked muzzle:

Initially every thing seems normal in the above pic, but after closer inspection you can see the bore is skewed towards 4:30 position. It is more apparent looking through the flash hider.



After measuring from the bore diameter to the outter-diameter of the barrel at 10:30 and 4:30 positions, it seems the bore exits off-center by ~0.011" towards 4:30.

I guess the question now is do I accept this and try to compensate in barrel timing, or is correctable with barrel timing? Would this be unsafe to shoot from?

Your opinions and input would be greatly appreciated.


July 14, 2007, 22:56
Your opinions and input would be greatly appreciated.


Sir, I would not accept that barrel for a build. I would return that to DSA in a "New York minute".

July 14, 2007, 23:09
that barrel is crap, nice calipers though

July 15, 2007, 08:22
I don't know what degree of automation they have when they make these things. But when that barrell was rechucked to make the boss for the muzzle threads and the threads themselves they must have not been paying attention and that came out eccentric. Could have even been a chip on one of the jaws of the chuck. Your bore could be perfectly straight and just the turning and threading on the end of the barrell is off?

July 15, 2007, 12:43
Has anyone linked the gigglee to this thread?

I'm dying to hear what he has to say


July 15, 2007, 12:54
Ideally, the threads should be concentric with the bore at the muzzle regardless of where the bore is in the barrel. It is hard to tell from the pictures but it looks as though the threads are concentric with the barrel OD and that the bore is off center. If that were the case it would make you wonder how DSA is doing this operation. If they're bad, I'd rather see them concentric with nothing per mountainman's surmise. Check the thread Topic: Turning a HB from a blank... (http://www.falfiles.com/forums/showthread.php?s=&threadid=206493) by gunsmith_tony to see it done the way that we'd all like it to be done every time. If you check thread Topic: Warning - Argie barrels (http://www.falfiles.com/forums/showthread.php?s=&threadid=153239) you can view pictures posted by gunplumber as he was losing money on a batch of barrels with off-center bores.

The barrel may be accurate, but if the shoulder was cut for the barrel at 21" then you may run out of sight adjustment before you can put POA on POI.

DSA is building a reputation on quality. You paid a goodly price for a barrel threaded for a muzzle device and got one that none of the smiths posting here would have let out of the shop. Send it back with regrets.

July 15, 2007, 12:59
VU ...to check it put it between centers ...then check the barrel shoulder face for TIR ...if its bouncing a few thousanths ...you can re-face the shoulder and get it all back on line ..
if its bouncin and you reinstall ...youll shoot into the weeds .....
.the threads are toast

youll have to re-turn the "concentric" major OD again .. ....and hope you nevev put a real brake on it ....it wont be there long ....TRULY SH**** WORK ...ON DSAs PART ....NO INSPECTION NO QUALITY .. ....bet all the shortened barrels are like that to a degree ..unless they just missed this one in the hellen keller inspection room ...have a hard time not seeing that one ....thats soo far out it hurts my colon just looking at the photo ........ ....personally id send it back and ask about there machining methods ...cause it aint workin for them

vu remember what we spoke of in the pm ....ya still want the tool ????

July 15, 2007, 15:35
What you are seeing is not unusual...for a service rifle grade barrel designed to perform within those expected parameters. However this is not what I would expect to see on a new production DSA barrel. Clearly, the threads and bore are not concentric.
Will this be a problem for you? Functionally; probably not. Aesthetically though...it's going to bug the hell out of you. I know it would me.
This isn't what you paid for. I'd send it back.

July 15, 2007, 18:56
When it ain't right, it ain't right. You shouldn't have to make any accomodations for anything you paid to have done right, or to be correct. Yes, send it back, and hold nothing back in the comments you may include for reasoning the return. There is no excuse (any way you look at it) for crap like that rolling out to good American Buyers. They should honor the return, as well as make this up to you, somehow. They (DSA) are American-made, and need to make every effort to uphold that as a fair and righteous claim. Settle for nothing less than CORRECT, and don't put it upon yourself to correct something you paid for and someone else may have half-assed. :mad:

July 15, 2007, 20:07
Thanks everyone for the input.

I think gunsmith_tony put it most succinctly:
Will this be a problem for you? Functionally; probably not. Aesthetically though...it's going to bug the hell out of you. I know it would me.
This isn't what you paid for.
... And it would BUG me to no end.

I guess I had already known what I was going to do from the start, but I suppose I was trying to rationalize any justification for the inferior workmanship, as well as to see if this barrel would even be serviceable. I will call DSA tomorrow for an RMA and chalk this up, hopefully, to a rare Q/A mistake. :? I expect they will do right.

Anyway, I initially intended to build a light-weight custom carbine, but now I'm leaning towards a para build. So, I should be able to exchange this 16.25" for the 18" para-length barrel. :biggrin:


July 15, 2007, 20:20
DSA has totally bungled 2 out of the 5 orders i've had with them. on the last one they stopped just short of calling me a liar. gotta watch 'em.

July 16, 2007, 06:58
If like tony said it seems like the threads, then DSA can take it back and turn it into a Para chop job. They come at no loss. Myself personally that would go in my rework pile before going out to the customer. Or at least announce the defect and sell it for a discount. It's usable and even with a muzzle device but you'll just have to bore out said muzzle device. The only way to tell if the bore is concentric is using carbide centers and dial indicator. I don't think they also messed up on the chamber threads, only then would the bore be eccentric.

July 16, 2007, 10:21
It is defective

it cannot be repaired.

Ghillie is a @)_&#$_&$@ idiot, and I'm really getting bored correcting him.

After I gave him 20 lessons, it looks like he finally figured ouyt what "boring" was and whay it cannot be done to something spinning between centers.

The gun will likely shoot 12-14 minutes off laterally with the sights aligned.

turning the barrel bewtween centers and recutting the shoulder works fine for barrels with NOTHING MOUNTED TO THEM!

I just turneda a Ruger 77 in .260 because the bore was out of concentricity with the OD.

But on the FAL, there is a front sight mounted to the barrel, that is a tight fit. Therefore, turning the barrel between centers will decrease the diameter at the gas block where it has to be a tight fit.

July 16, 2007, 16:01
Return Merchandise
D S Arms, Inc.
27W990 Industrial Avenue
Lake Barrington, IL 60010

Dear sir or madam:

I am enclosing a copy of my order invoice from July 9th for FAL parts: one SA58 FAL 16.25" Carbine Chrome Moly Barrel(00116), one Belgian Type Short Flash Hider(002D), one Steyr Short Flashider(002H), and various other items. I took delivery of the shipment on July 12th, and I verified all items were present and found no apparent damage. As time permitted, I was able to test fit these new parts this past weekend.

Unfortunately, I encountered these issues:

1. The barrel seemed perfectly fine externally except for a minor flat spot on the muzzle threads. After test-fitting the Steyr flash hider, which threaded onto the barrel without issue, I inspected the flash hider for proper fit and, to my dismay, discovered the muzzle end of the bore did not appear to be centered or concentric with the outer profile of the barrel. It was not initially perceptible, but looking through the attached flash hider, the phenomenon was quite apparent. Please see the included photos for illustration.

2. Since I had purchased a standard left-hand threaded Belgian Type Short Flash Hider to replace the original muzzled device on my Imbel barrel, I decided to test fit it to the aforementioned barrel to make certain the Steyr muzzle device was not at issue. However, the device would not thread onto the barrel, which lead me to believe a right-hand thread device was mistakenly sent to me.

I think you would understand that I can not accept these parts as they are; therefore, I respectfully request to have them exchanged. If you require further correspondence, I can be reached via cell phone at ###-###-###, or please email me at vu01(at)yahoo(dot)com.

Candidly, I have been extremely pleased with all my commerce with DSA to date. I believe your goods are of great quality, and I trust this instance is a rare exception. I look forward to your continued offering of top-notch products and excellent service.


I included the original photos for reference.

I got an RMA# today. Hopefully, I can get a new barrel back quickly so I can move forward with my build. I now know to check for concentricity of the bore first. I'll keep you all posted.

Again, thanks for the knowledge.


Orion 762
July 17, 2007, 01:03
Interesting that DSA would let a barrel like that "out the door", especially their own chrome-moly "nice" barrels.

I've rethreaded the chopped end of a few barrels using only a hand-held "die", and have wondered a bit about the "concentricity" issue with the FH. I normally put a "target crown" on the barrel after the chop/rethread operation, but I'm wondering how much good the "target crown" really does burried behind the FH?

My understanding is that the gas pressures behind the bullet need to escape the muzzle in a concentric fashion in order to smoothly guide the bullet on its exit out the muzzle. A "non-cocentric" FH in front of the crowned barrel would obviously "upset" this gas flow. Not sure how much effect this will have - but it can't be "good" for accuracy if gases are venting in weird directions just as the bullet clears the muzzle.

On my most accurate rifles (less than 1 moa)) with target crowns and no FH, after firing several rounds I can look at the muzzle closely and see the "star pattern" of the carbon tracks. Very accurate rifles give a very uniforn and concentric "star burst pattern", while those with any crown imperfections show a lopsided "burst" pattern. They also are 4 moa at best barrels.

My "guess" is that even a well crowned muzzle with a non-concentric FH will render the "target crown" somewhat useless.

Orion 762