Help with muzzle threads on a expensive custom barrel

[Serpico1985]

Hey guys. Hoping for a reality check. Buddy a mine just got a new barrel for his precision AR. He's gonna have two different uppers to do longer range AR15 shooting with. Anyway, this is the barrel for the 2nd upper and I've got some questions for the group if you will indulge me.

When he showed it to me the muzzle threading looked way off to me but I'm not a long gun guy. Here's what we're dealing with. It's threaded 5/8x24 and this is the exact condition as received.

Pic 1

Pic 2:

Pic 3:

I thought these threads looked way to flat but again I'm not an expert. I did a little looking around for how to measure threads and purchased a Brown and Sharpe thread wire set to measure the pitch diameter. Should be here in a few days. My friend intended to shoot this thing suppressed with his 30 cal direct thread thunder beast. I told him definitely not until we get some info on these threads.

I took a couple initial measurements and as it sits right now the threads are .604" OD. I'll get the pitch diameter dimension when the wire set gets here.

I also measured from the face of the muzzle to the shoulder and it was .668". I watched the video by Thunderbeast saying this dimension should be .600" to prevent the threads from protruding into the can and getting caked up making removal a pain.

Finally, here is a short video of the barrel with my friends TB can threaded most of the way on. Is this movement normal? My can is a CB mount so I have nothing to compare it to.



I don't want to say where he got the barrel from until they have a chance to address it. This barrel was expensive though, over $800 with a bolt and gas tube. I'm also concerned that the machining is so poor on the shoulder that even if the threads were ok it could shift the can one way or another as it seats.

Thanks in advance for any help.

 

[_Windrider_]

Yeah those threads are no Bueno. Who did the work?

 

[_Windrider_]

Direct from TBAC. Thos threads are not supposed to be flat. My AR's have adapters on them or id sed a pic of the threads to show but you can see from this picture the problem.

 

[_Windrider_]

For AR Barrels, I trust craddock precision exclusively.

 

[whatsupdoc]

5/8-24 Major Diameter is .625 but I think the minimum Major Diameter is .617, so the threads are not to specification.

 

[Rubicon Precision]

Don’t waste any more time worrying about the pitch diameter. The major diameter is .012”-.013” under spec. Send it back for a replacement.

 

[LivetohuntID]

Ya I could use my thread disk software for you, but I can say those threads aren’t to spec. I have seen factory barrels like that many times before though.

I mean they probably gage fine, but yea, the thread major is under spec

that shoulder looks like dog shit too…

 

[Supersubes]

Garbage, send it back.

 

[FisherT&C]

Warranty! For sure.

 

[Serpico1985]

Thank y’all very much for the info. I don’t want to say whose barrel it is because

1. it’s not my barrel
2. I want to give the maker a chance to fix it

 

[SmartDonkey]

If it was going to be a muzzle brake or flash hider I would probably test the barrel out and see how it shoots- Still enough threads there to safely secure one of those- but no way would I put a can on those.

 

[Wannashootit]

So much for QC...
Sure, defective product can be turned out by anyone whether produced by a state of the art machining center or manual.
But when a v-thread looks more like an acme thread and it ends up with the customer, it's obvious no one even looked at this barrel before it shipped.

 

[TurboTrout]

Hell of a QC job lol

I mean how many hands did that go through that all were like “meh, good enough”

I can forgive errors hard to spot, but that shits obvious from the naked eye, and it’s also shiny part of a black barrel, like it draws the eye.

I’d send it back, get the money, and use a known good OEM.

 

[GrumpyOleFart]

Rough as guts.
Send it back.

 

[Ledzep]

It's threaded 5/8x24 and this is the exact condition as received.


I took a couple initial measurements and as it sits right now the threads are .604" OD. I'll get the pitch diameter dimension when the wire set gets here.

I also measured from the face of the muzzle to the shoulder and it was .668".

Wrong. Send it somewhere else to get re-threaded.

You don't need to waste your time.

I probably thread and chamber 5-10 barrels a year, for myself, work, friends, etc... Never once have I done a 5/8-24 thread outside of a .621-.624" diameter window. Someone is either incompetent or not paying attention.

 

[Serpico1985]

We spoke to the guy before knowing for certain how jacked up the threads are. Guy said he guaranteed 1/2 moa from his barrels so if there is any issue he‘ll replace it. Seems like a ill-advised business plan especially for AR barrels.…. But a guarantee is a guarante. My buddy plans to build the upper out and see how it shoots. If it shoots well he’ll get it re-threaded from a reputable company. The barrel is from a bartlein blank, 6mm ARC, 22”.

My buddy has patience issues. Doesn’t want to wait how ever many weeks it would be to get a replacement.

I’ll let you guys know how it shoots.

 

[_Windrider_]

We spoke to the guy before knowing for certain how jacked up the threads are. Guy said he guaranteed 1/2 moa from his barrels so if there is any issue he‘ll replace it. Seems like a ill-advised business plan especially for AR barrels.…. But a guarantee is a guarante. My buddy plans to build the upper out and see how it shoots. If it shoots well he’ll get it re-threaded from a reputable company. The barrel is from a bartlein blank, 6mm ARC, 22”.

My buddy has patience issues. Doesn’t want to wait how ever many weeks it would be to get a replacement.

I’ll let you guys know how it shoots.

Well he’s gonna be waiting a year to replace the silencer he destroys shooting with those threads.

 

[BuildingConceptsllc]

I wouldn't try that plan out man. Send it back asap and get a new one that isn't complete trash.

 

[moosemeat]

Hes loosing 25% thread engagement. Not insignificant. The length is a bigger concern. Carbon build up on threads in the supressor that are already suffering from lack of engagement on the flanks is asking for problems. Shoot it unsurpassed. If it shoots send it to LRI with a C note to have it bobbed .6 and rethreaded 100% correct.

 

[Stoweit]

Yea, get a new one. That one is trash, worst looking threads I’ve seen in a long time.

 

[Serpico1985]

We’re not going to shoot it with the can on guys. I’ve already told him to send it back now for a refund not an exchange. But my friend is hard headed. I think we all know someone like that. I try not to get wrapped up in his decisions. I speak my $0.02, help if/when I can but it’s his money.

I really do appreciate the info on the threads though. I got the wire gauges today and came up with .595” which is in the class 2 range but still is a no go for the OD and length.

Thanks again

 

[GrumpyOleFart]

One thing that boils my piss, is good money exchanged for shit work.
Hope things work out better.

 

[NiteQwill]

Well, since your friend wants to keep it... (Dumb idea, honestly) It doesn't matter anymore...

Who is the one who did the barrel work? So we can avoid trash work for money spent.

Remember, this forum is intended to help people. And I think the honest thing to do is let other members know so they can avoid the same issue your friend has.

 

[Rubicon Precision]

Who is the one who did the barrel work? So we can avoid trash work for money spent.

Remember, this forum is intended to help people. And I think the honest thing to do is let other members know so they can avoid the same issue your friend has.

The builder hasn’t even been made aware of the issue, nor been given the opportunity to correct it. Probably no need to toss the builder under the bus at this point.

 

[NiteQwill]

He already said his friend doesn't want to fix it. Why not tell us? Otherwise, it will be forever repeated to another customer who WILL not know the difference, screw on an expensive can, and pay dearly for a mistake that can be easily avoided.

 

[gonzaga]

Your friend is a fkn idiot if he doesn't want to get it taken care of....
Give the builder a chance to make it right, if they don't then flame on.

 

[308guru]

It appears to be fluted. If the threaded portion is removed and threads cut farther back it will be into the flutes. Not a deal breaker but cosmetically not what most people are after.

A correctly made replacement is really the only right option in my mind.

 

[BuildingConceptsllc]

Can someone who knows about machining explain what happened? To my amateur eyes it looks like either the threads didn't get finished being cut, or something majorly stripped them or something??? I just cant understand how that went out???? It's so blatant and obvious??? Every shop puts out a mistake or two now and then, I just don't understand this one because it's so apparent.

 

[Supersubes]

Can someone who knows about machining explain what happened? To my amateur eyes it looks like either the threads didn't get finished being cut, or something majorly stripped them or something??? I just cant understand how that went out???? It's so blatant and obvious??? Every shop puts out a mistake or two now and then, I just don't understand this one because it's so apparent.

The thread major diamter for 5/8-24 is .625. Most of us cut them a little smaller as ledzep mentioned above. The OP’s major diameter is .604(a LOT smaller). In other words, the guy cut the tenon too small before threading started.

 

[Ledzep]

Can someone who knows about machining explain what happened? To my amateur eyes it looks like either the threads didn't get finished being cut, or something majorly stripped them or something??? I just cant understand how that went out???? It's so blatant and obvious??? Every shop puts out a mistake or two now and then, I just don't understand this one because it's so apparent.

3 things going on with any thread. Major diameter, Minor diameter, and Pitch diameter.

In this case, the major diameter should have been .617-.625", but it was cut down to .604". I think the OP or his friend may eventually measure the pitch diameter (pitch diameter basically controls the "fit" of the thread), but the short answer was the threads were cut at least to where they needed to be, maybe too deep... but the big goof here is that the OD was turned down to .604" before they started threading.

They made this instead:

 

[BuildingConceptsllc]

3 things going on with any thread. Major diameter, Minor diameter, and Pitch diameter.

View attachment 7710397

In this case, the major diameter should have been .617-.625", but it was cut down to .604". I think the OP or his friend may eventually measure the pitch diameter (pitch diameter basically controls the "fit" of the thread), but the short answer was the threads were cut at least to where they needed to be, maybe too deep... but the big goof here is that the OD was turned down to .604" before they started threading.

Ok, so this is why I asked... so they cut the diameter too small before they even started to thread it, then threaded it anyway.... I think I'd just ask for my money back instead of a new one. It's hard for me to believe whoever did it, didn't know right?

 

[Ledzep]

It's hard for me to believe whoever did it, didn't know right?

You hope so... lol.

 

[NukeMMC]

Have a competent smith put 9/16-24 UNEF3A in the same location. Area419 makes a Hellfire adapter that size and it works fine on my TacOps Lima51 with TBAC Ultra7. Now just waiting on my TacOps can to be released from ATF jail.

Another option, since it's an AR15, is to go 1/2-28 and use an adapter to 5/8-24

 

[BuildingConceptsllc]

You hope so... lol.

I'm not sure which would be worse honestly

 

[Rubicon Precision]

The

Can someone who knows about machining explain what happened? To my amateur eyes it looks like either the threads didn't get finished being cut, or something majorly stripped them or something??? I just cant understand how that went out???? It's so blatant and obvious??? Every shop puts out a mistake or two now and then, I just don't understand this one because it's so apparent.

The major diameter was machines too small.

But it’s pretty apparent, even to the naked eye. Even if a shop doesn’t gauge every thread on a proven program, that one is hard to miss visually.

 

[Elite_KG]

Doesn’t look like you can re-thread that barrel without cutting back into flutes. No way I would cut back into flutes in a brand new custom barrel. Likely your Smith trashed your barrel unless he lops off the threads and crowns it for an unthreaded version; possibly to resell.
Either way, you will likely need a new barrel. Sorry for your situation. I just had a similar circumstances with a threaded barrel from a local smith.

These threads were purposely cut 0.010” oversized. Problem was the 0.003” shoulder left on the the face of the barrel. The lip has permanent marker on it abs you can see the light hitting it just behind the threads (about at the location of the outer diameter in the face of the barrel).

 

[Serpico1985]

For anyone who wants closure my friend sent the barrel to Mile High. Less than a two week turn around. Threads look perfect and it's exactly .600" from the muzzle to the shoulder.

We're going shooting this Friday. Gonna ring it out on the 1200 meter range and see what it'll do.

 

[_Windrider_]

That’s a shame. He should have sent it back to whomever did it and demanded a full refund. Instead the “smith” gets away with it and your friend gave up an inch or so on his barrel and ruined the flutes.

Now tell us who did it so we can all avoid this tragedy

 

[NiteQwill]

There is no closure. You will fail someone by having their barrel suffer the same fate because the smith was not named. That's a damn shame.

 

[Im2bent]

As stated the smith does not deserve to profit from his crap work and future customers don't deserve to be blind sided.

 

[Im2bent]

Hey guys. Hoping for a reality check. Buddy a mine just got a new barrel for his precision AR. He's gonna have two different uppers to do longer range AR15 shooting with. Anyway, this is the barrel for the 2nd upper and I've got some questions for the group if you will indulge me.

When he showed it to me the muzzle threading looked way off to me but I'm not a long gun guy. Here's what we're dealing with. It's threaded 5/8x24 and this is the exact condition as received.

Pic 1
View attachment 7709439

Pic 2:
View attachment 7709440

Pic 3:
View attachment 7709441

I thought these threads looked way to flat but again I'm not an expert. I did a little looking around for how to measure threads and purchased a Brown and Sharpe thread wire set to measure the pitch diameter. Should be here in a few days. My friend intended to shoot this thing suppressed with his 30 cal direct thread thunder beast. I told him definitely not until we get some info on these threads.

I took a couple initial measurements and as it sits right now the threads are .604" OD. I'll get the pitch diameter dimension when the wire set gets here.

I also measured from the face of the muzzle to the shoulder and it was .668". I watched the video by Thunderbeast saying this dimension should be .600" to prevent the threads from protruding into the can and getting caked up making removal a pain.

Finally, here is a short video of the barrel with my friends TB can threaded most of the way on. Is this movement normal? My can is a CB mount so I have nothing to compare it to.



I don't want to say where he got the barrel from until they have a chance to address it. This barrel was expensive though, over $800 with a bolt and gas tube. I'm also concerned that the machining is so poor on the shoulder that even if the threads were ok it could shift the can one way or another as it seats.

Thanks in advance for any help.

He had the chance, no?

 

[GrumpyOleFart]

Glad it got sorted for you.

 

[Serpico1985]

Anyone who wants to know the maker that did the shit job PM me.

 

[Im2bent]

So did your friend reach out the the retailer or he went straight to Mile High?

 

[blackblue]

Anyone who wants to know the maker that did the shit job PM me.

Why not post it for any that may happen to search the Smith's name and they can see this.

 

[TurboTrout]

For anyone who wants closure my friend sent the barrel to Mile High. Less than a two week turn around. Threads look perfect and it's exactly .600" from the muzzle to the shoulder.

We're going shooting this Friday. Gonna ring it out on the 1200 meter range and see what it'll do.

View attachment 7738409

View attachment 7738410

View attachment 7738411

So he paid more and the finish on the end of that new barrel looks like something that might not even be presentable enough to be in the blem bin?

If he’s happy that’s all that matters, but damn

 

[Steel head]

That looks far worse than the first threads I ever cut on a barrel.

 

[Serpico1985]

The barrel was purchased from Precision Firearms (precisionfirearms.com). It was purchased as a already completed barrel (not as a blank that was made to customer spec) from the "in stock barrels" section.

 

[b6graham]

lol there's legit no way i'd ever pay that for such a shit barrel and then may MORE to get it fixed and not what i wanted in the first place. my god what a ripoff

 

[Clob McStrunk]

"friend"