Fixing barrel threads for muzzle device

[GunnyUSMC]

I have a 6.5 creedmore barrel fitted by Altus. It came with a self-tapping muzzle break. The existing muzzle device does fit but the nature of the device is that it is not designed to screw flush with the barrel due to the self tapping nature of the muzzle device. After removing the muzzle break and installing the thread protector, i found out the thread protector wont screw on fully and flush with the barrel. It appears the innermost threads are damaged.

To solve this problem, i purchased a die for 5/8x24 to see if it can fix the threads and correct the problem. However, i cannot seem to get the die to even start threading on the barrel. I am being very cautious so as to not damage the existing threads.

My question is whether or not i should have purchased a specific thread type for the 5/8x24 die? Alternatively, this chinese made die is just not properly made.

Thanks

 

[Supersubes]

Self tapping muzzle brake? Never heard of such a thing. You ordered it from Altus like this? Sounds like something is out of spec to me.

 

[Taylorbok]

What is a self tapping muzzle brake? That sounds like a terrible idea.
Is your thread for sure 5/8-24? You should be able to at least get it started by hand

 

[TheOfficeT-Rex]

Can we get a picture of the muzzle threads?

 

[Baron23]

@AccuSol-ERN - tagging Ern on this.

@GunnyUSMC - Gunny...do you perhaps mean "self-timing" brake and not "self-tapping"? I have never, ever heard of a self-tapping brake and, by your own statement, your barrel was threaded 5/8 x 24 by Ern (Altus).

And what is the brand name of the break.

Personally, I would def not try to clean up any barrel threading myself. Many here are pro gunsmiths, many are amateur gunsmiths, and then there are many like myself who have no business trying to be a gunsmith. haha

Please do post close up pics of the threads and especially the area you think is buggered up.

If the threads are not right, I'd just send it back to Ern to clean up...or if you have competent gunsmiths you trust in your area then I'm sure one of them could clean up some muzzel threads. I would not try to fix it with a Chinesium die...but, as I said, I'm good at breaking things with tools.

Cheers

 

[Mordamer]

I'm sure you meant "self timing" muzzle brake. A self timing brake does not damage threads unless it is installed improperly.

You very likely purchased a die that is for 2A class threads. The muzzle threads are class 3A. You would likely be able to thread the die on with a lot of force and lube and the end result would be threads that are too loose. Don't use a die on the threads. You need to find a competent gunsmith who can fix your muzzle threads properly on a lathe.

 

[AccuSol-ERN]

Hi all.

That sounds like quite the issue.

Please don't run a cheapie die on the existing thread.

What brake did it have and what thread protector are you trying to install? I relief cut all muzzle threading I do......because it is the only way to account for the large variety of muzzle devices out there....some have a relief in the brake......some don't. I also cut everything to a class 3 fit and thread mic to check. Beware there are some muzzle devices that state class 2 fit in the specifications. Class 2 is a general fit and class 3 is more precise and should be the standard in firearms.

Please post a pic of the damaged thread area. I also put a little chamfer on the last thread before the relief to avoid the runout wire thread edge.

If you purchased a cheapie thread protector, you may start there. If you need a recommendation for one, let me know. Keep us posted on how you proceed.

Ern

 

[LeftyJason]

Hi all.

That sounds like quite the issue.

Please don't run a cheapie die on the existing thread.

What brake did it have and what thread protector are you trying to install? I relief cut all muzzle threading I do......because it is the only way to account for the large variety of muzzle devices out there....some have a relief in the brake......some don't. I also cut everything to a class 3 fit and thread mic to check. Beware there are some muzzle devices that state class 2 fit in the specifications. Class 2 is a general fit and class 3 is more precise and should be the standard in firearms.

Please post a pic of the damaged thread area. I also put a little chamfer on the last thread before the relief to avoid the runout wire thread edge.

If you purchased a cheapie thread protector, you may start there. If you need a recommendation for one, let me know. Keep us posted on how you proceed.

Ern

Yet saami looks like they did the stupid thing and says class 2.

Firearm Suppressor Thread and Socket Drawings - SAAMI

NOTE: The muzzle thread and socket drawings below are posted in accordance with SAAMI’s mission to promote safety, interchangeability, reliability and quality and are available to the public, without restriction. These drawings are not an approved American National Standard (ANS) at present. Any...

saami.org

 

[GunnyUSMC]

@AccuSol-ERN - tagging Ern on this.

@GunnyUSMC - Gunny...do you perhaps mean "self-timing" brake and not "self-tapping"? I have never, ever heard of a self-tapping brake and, by your own statement, your barrel was threaded 5/8 x 24 by Ern (Altus).

And what is the brand name of the break.

Personally, I would def not try to clean up any barrel threading myself. Many here are pro gunsmiths, many are amateur gunsmiths, and then there are many like myself who have no business trying to be a gunsmith. haha

Please do post close up pics of the threads and especially the area you think is buggered up.

If the threads are not right, I'd just send it back to Ern to clean up...or if you have competent gunsmiths you trust in your area then I'm sure one of them could clean up some muzzel threads. I would not try to fix it with a Chinesium die...but, as I said, I'm good at breaking things with tools.

Cheers

uggg.... my bad, i misspoke. It is a "Self-Timing" muzzle break (had the word "Tapping" on the brain). It is the "GEN 3 LITTLE BASTARD SELF TIMING MUZZLE BRAKE*"

Please don't run a cheapie die on the existing thread.

What brake did it have and what thread protector are you trying to install? I relief cut all muzzle threading I do......because it is the only way to account for the large variety of muzzle devices out there....some have a relief in the brake

I wanted a thread protector that fit perfectly and blended in as an extension of the finished barrel. Altus mounted the barrel but I couldnt get Altus to be responsive to my request to cut me a thread protector (very frustrating story that made me not want to do business with them in the future). I had no other option other than to get another gunsmith do it. The new thread protector looks and fits great and threads on perfectly until it gets to within about 1/8" from the base of the barrel. I also have a cheapO thread protector that does the same in that it threads onto the barrel until it gets to that last 1/8".

I will get and upload some pics. And I agree with getting a proper gunsmith to resolve. Dave Tooley is building my new 300 PRC and I will likely just wait until i see him and then ask if it is something he can assist with. Other than this issue, this gun rocks and i do not want to take a chance at messing anything up. I was just hoping for a quick and easy fix.

Thanks for all the feedback

 

[spife7980]

I wanted a thread protector that fit perfectly and blended in as an extension of the finished barrel. Altus mounted the barrel but I couldnt get Altus to be responsive to my request to cut me a thread protector (very frustrating story that made me not want to do business with them in the future). I had no other option other than to get another gunsmith do it. The new thread protector looks and fits great and threads on perfectly until it gets to within about 1/8" from the base of the barrel. I also have a cheapO thread protector that does the same in that it threads onto the barrel until it gets to that last 1/8".

I will get and upload some pics. And I agree with getting a proper gunsmith to resolve. Dave Tooley is building my new 300 PRC and I will likely just wait until i see him and then ask if it is something he can assist with. Other than this issue, this gun rocks and i do not want to take a chance at messing anything up. I was just hoping for a quick and easy fix.

Thanks for all the feedback

That @AccuSol-ERN you just quoted... thats the altus smith. Seems he is more responsive than you might be noticing.

 

[GunnyUSMC]

That @AccuSol-ERN you just quoted... thats the altus smith. Seems he is more responsive than you might be noticing.

WOW! good to know.

Like i said above, my gun built by Altus rocks and i really love it.

My issue with Altus was the sales person who never follows-through as promised. I wont elaborate more than that here.

 

[msgriff]

Not to be obtuse, but is your thread protector indexing against the crown?

 

[GunnyUSMC]

Not to be obtuse, but is your thread protector indexing against the crown?

I considered that but with the thread protector screwed on as far as it will go, there is a gap between the crown and the outer lip of the thread protector.

I think the following pictures will help demonstrate what is going on:

• one shows the muzzle brake fully mounted
• one shows the muzzle brake mounted without the locking ring
• two shots of the threads, one from each side
• two show the thread protector from slightly different angles

 

[Baron23]

Hi @GunnyUSMC - too funny. Yeah, @AccuSol-ERN is indeed Ern of Altus (hahaha...ooops, hate when that happens! haha)

Ern is widely considered to be an expert gunsmith/precision rifle builder and he is very respected among his peers and shooters.

I have a BA spun up by Ern and I own a bore scope. The chambering of this barrel was perfect as far as I can tell. VERY symmetrical and even leade in the throat area. And I also asked for a thread protector, had zero issue in conveying that to the sales person (his first name is Al....same guy as you???...because I found Al to be very responsive and accurate with my order) and it fits on the muzzle threads perfectly.

Only thing I will change going forward is to talk to him about reducing freebore a bit when I get him to spin my next barrel. But I ASKED for a SAAMI chamber and a SAAMI chamber is what I got. I'm very happy with my decision to go with Altus.

I know...and many others here will also testify...that Ern def knows how to cut threads square, plumb, and true. Dunno what happened to yours.

If I may suggest, nicer pictures of the threads would be helpful. You need to be very steady and very close (your phone has a macro photo function in the camera app if it was made later than 1988! haha). I'm not the expert you want looking at this, but I can't make out anything useful in the two thread pics you posted.

Best of luck....and please def send Ern better close up pics of your threads (or post them here and tag him) as at least I believe he deserves a chance to look at the problem, diagnose it, and suggest how to rectify.

Cheers and best of luck.

 

[kthomas]

I would trust Ern and do what he recommends.

I've used a 1/2x28 die to clean-up damaged threads on an ar-15 barrel, it "worked" but I would be a lot more nervous doing it on a precision rifle of any value.

 

[AccuSol-ERN]

Hello again.

Sorry to hear about your lackluster experience with the Altus sales folks.........I can assure you it is not the norm.

After looking at your pics, I have come to the conclusion the issue is with the thread protector.......I will explain why. In the picture that shows the APA without the self timing nut, it screws all the way to the barrel shoulder. I looked at the same APA brake here in my shop and there is no thread relief cut into the body of the APA brake.........APA uses the self timing nut to provide the thread relief that you normally see on a one-piece brake. Based on this, the threads are in perfect working order to allow a correctly sized muzzle device to be screwed on.

From here, this leaves thread size (or class fit). I can not speak to the specification of the thread protector as I didn't machine it. In my experience, most aftermarket thread protectors are cut on the very loose side of acceptability to ensure they fit on everything.

Now look at the pic that shows the end of the barrel and its relation to the visible end of your thread protector. It is common for people who make thread protectors to thread the entire internal and then come back and cut the relief. When it is done this way it is very important to cut the relief from the inside outward..........otherwise you risk pushing a burr (actually the wire edge of the last thread) into the V of the thread next to it. If you leave the aforementioned burr in the thread you will not be able to screw the barrel in past that. I believe this is what is happening to you. You can clean this up by running a 5/8-24 tap down the thread protector to remove or move this burr out of the way of the male thread. If you can wait until you see Dave Tooley I am confident that Dave can handle this very elementary task.

It's a bummer it doesn't have an Altus thread protector, my stuff fits better and looks cleaner.

Ern

 

[Baron23]

Hello again.

Sorry to hear about your lackluster experience with the Altus sales folks.........I can assure you it is not the norm.

After looking at your pics, I have come to the conclusion the issue is with the thread protector.......I will explain why. In the picture that shows the APA without the self timing nut, it screws all the way to the barrel shoulder. I looked at the same APA brake here in my shop and there is no thread relief cut into the body of the APA brake.........APA uses the self timing nut to provide the thread relief that you normally see on a one-piece brake. Based on this, the threads are in perfect working order to allow a correctly sized muzzle device to be screwed on.

From here, this leaves thread size (or class fit). I can not speak to the specification of the thread protector as I didn't machine it. In my experience, most aftermarket thread protectors are cut on the very loose side of acceptability to ensure they fit on everything.

Now look at the pic that shows the end of the barrel and its relation to the visible end of your thread protector. It is common for people who make thread protectors to thread the entire internal and then come back and cut the relief. When it is done this way it is very important to cut the relief from the inside outward..........otherwise you risk pushing a burr (actually the wire edge of the last thread) into the V of the thread next to it. If you leave the aforementioned burr in the thread you will not be able to screw the barrel in past that. I believe this is what is happening to you. You can clean this up by running a 5/8-24 tap down the thread protector to remove or move this burr out of the way of the male thread. If you can wait until you see Dave Tooley I am confident that Dave can handle this very elementary task.

It's a bummer it doesn't have an Altus thread protector, my stuff fits better and looks cleaner.

Ern

Wow, good eyes....I couldn't make heads or tails out of that pic with the brake minus lock-nut...well, until I read your post and then saw this pic on APA's site. That's why you're a pro and I keep telling myself "don't try this at home, Baron!" LOL Then it was clear what you are talking about seeing. Cheers

 

[GunnyUSMC]

Hello again.

Sorry to hear about your lackluster experience with the Altus sales folks.........I can assure you it is not the norm.

After looking at your pics, I have come to the conclusion the issue is with the thread protector.......I will explain why. In the picture that shows the APA without the self timing nut, it screws all the way to the barrel shoulder. I looked at the same APA brake here in my shop and there is no thread relief cut into the body of the APA brake.........APA uses the self timing nut to provide the thread relief that you normally see on a one-piece brake. Based on this, the threads are in perfect working order to allow a correctly sized muzzle device to be screwed on.

From here, this leaves thread size (or class fit). I can not speak to the specification of the thread protector as I didn't machine it. In my experience, most aftermarket thread protectors are cut on the very loose side of acceptability to ensure they fit on everything.

Now look at the pic that shows the end of the barrel and its relation to the visible end of your thread protector. It is common for people who make thread protectors to thread the entire internal and then come back and cut the relief. When it is done this way it is very important to cut the relief from the inside outward..........otherwise you risk pushing a burr (actually the wire edge of the last thread) into the V of the thread next to it. If you leave the aforementioned burr in the thread you will not be able to screw the barrel in past that. I believe this is what is happening to you. You can clean this up by running a 5/8-24 tap down the thread protector to remove or move this burr out of the way of the male thread. If you can wait until you see Dave Tooley I am confident that Dave can handle this very elementary task.

It's a bummer it doesn't have an Altus thread protector, my stuff fits better and looks cleaner.

Hi Ern,

Thanks much for your insight and analysis.

I have said this already and want to reiterate... I love my gun. Throughout my life i have shot any number of military weapons. My favorite was an M-14 I shot in the inter service matches in Quantico VA many years ago. That was my first experience with shooting 1,000 yards only this was with iron sights. My new gun that you built made me feel like i had my M-14 in my hands again, only this time, it was a bolt gun. It is my first Bolt gun and the memories and emotions it conjures up, well it is hard to explain. I love my gun and thanks for that.

I will follow your recommendations. BTW... I do have two thread protectors, one was custom made by another gunsmith and the other is a cheapO that i just kept around in the case of an emergency. Neither one will screw fully onto the barrel. I dont have a tap so I will just hold off doing anything until I see Dave.

Also, I did take the advice above and got some better pictures below. Let me know if this helps at all.

 

[AccuSol-ERN]

I am glad you like your rifle, its hard to go wrong with an Impact/Foundation combo. I build a ton of similar spec rifles.

I don't see anything obvious. I am glad you tried a second one. Do both thread protectors screw on to the same point? When they stop is it a firm stop? Or a increasingly harder to turn then stop?

If my questions get annoying, please let me know. Just trying to figure out the problem to help both you and future customers.

I am confident Dave can resolve it with hands on in a few seconds.

Ern

 

[GunnyUSMC]

Ern, questions not annoying in any way.

Both react the same and the same place. They get increasingly harder, not a hard stop.

 

[spife7980]

 

[AccuSol-ERN]

Sounds like a thread fitment issue. Dave can probably run a known good 5/8-24 class3 tap down both thread protectors and they will be fixed.

If the APA didn't screw on all the way and given I check my threads with both a thread mic when machining and finally assembly with a female go gage, I would question my threads. Not saying I am above a mistake, but I would need to make several during the same operation on the same barrel.

I do cut to the tight side of ASME thread pitch diameter though. Maybe this is a perfect storm of my threads being just under maximum and the thread protector makers being just over minimal.

Ern

 

[GunnyUSMC]

agreed... thanks Ern

 

[AccuSol-ERN]

No problemo.

Please let me know what happens after you see Dave. I don't know Mr. Tooley personally, but I've heard his name associated with top quality for years......if not decades. You are definitely in good hands there.

Ern

 

[GunnyUSMC]

will do... we dont have a date set yet but will do