View Full Version : Loose barrel extension on melonite treated barrel...
pathfinderheli
06-10-14, 19:08
I have a BCM SS410 18" Rifle Gas that was dimpled and then melonited. I was confirming the torque (20lbs) / rocksetting the brake on it and the barrel rotated. I figure I had sheared the indexing pin or broke the upper receiver but noticed that the extension was not rotating....
Pulled the barrel off the build (not happy as this was a URX 3.1) and noted that in fact the barrel extension has come loose.
Is there a way to fix this i.e. who can I send this to for fixing? I dumped a ton of money in this barrel so if it can be saved that would be awesome....
EDIT:
pic removed as it bears no contribution to the issue.
You should be contacting BCM as per the site rules.
Re-opened as I may have misunderstood this. Was this something done aftermarket? If so, you are screwed because you can't simply retorque a barrel extension into place. That's because the gas port is drilled after the barrel extension is torqued to the barrel.
It's been cautioned that meloniting a barrel after the extension is installed can loosen it due to the high heat required for meloniting and the different materials...
Can't he get someone like ADCO to weld the port and drill a new one?
pathfinderheli
06-11-14, 03:29
Sorry if I wasn't clear on what the issue was. Dimpling and Meloniting was done aftermarket by two separate companies. As the poster above stated, after some research, it does look like this can be a common problem with Meloniting a barrel.
Robb Jensen
06-11-14, 04:49
I had one come lose after meloniting. I just carefully Rocksett the extension back on being very careful to get it where it was and after that cured (after 24hrs) installed a new index pin. Put the pin in last because I used the mark the original pin left in the threads as a guide. Then when I torqued the barrel nut I DID NOT use a Geissele Reaction Rod I used an upper receiver block and then triple checked headspace with a NOGO, FIELD and Colt FIELD II gauge, it worked out fine.
constructor
06-11-14, 08:43
I have a BCM SS410 18" Rifle Gas that was dimpled and then melonited. I was confirming the torque (20lbs) / rocksetting the brake on it and the barrel rotated. I figure I had sheared the indexing pin or broke the upper receiver but noticed that the extension was not rotating....
Pulled the barrel off the build (not happy as this was a URX 3.1) and noted that in fact the barrel extension has come loose.
Is there a way to fix this i.e. who can I send this to for fixing? I dumped a ton of money in this barrel so if it can be saved that would be awesome....
EDIT:
pic removed as it bears no contribution to the issue.
The only real way to do it right is for someone that has a pile...like 100 barrel extensions. Install them torqued correctly until 1 lines up perfectly or is very close to aligning on the before TDC side. Then turn .001 -.002 off the front of the extension so it will turn a little further to align at the required torque.
I fear all these new companies starting to do Melonite barrels will have these issues unless they torque the extensions after treatment and then drill the gas port and dimple. One company that does Melonite treatment is advising people to drill the alignment pin hole deeper and use a longer pin...That will not work long. The extension is not torqued tight, it will loosen and the barrel will wobble in it. Accuracy will go to crap and all the pin does is hold it loose.
This doesn't sound good at all. Not sure about saving it!
The company that did the meloniting/nitriding should step up and resolve this for you. But I would probably try to fix it myself. Loosening barrel extensions while meloniting is a fairly common problem, although the companies that do it say it rarely or never happens. This is why I only get my melonite barrels from companies that tighten the barrel extension and drill the gas port after meloniting/ntriding.
pathfinderheli, Rocksett might not be the best thing to use. I have limited experience with Rocksett. But what you want is obviously very high strength, very high temperature resistance, and good chemical/solvent compatibility. You may want to use one of the (numerous) Loctite products. The people at Loctite have always been very knowledgeable and helpful about product selection when I called them. Since you say this was an expensive build, I would probably put a lot of time into picking the best thread locking product.
Also, checking the headspace should not be necessary if it was headspaced properly to begin with. But it doesn't hurt to check it after you have it assembled again like Robb Jensen did.
Good luck with it, and keep us updated if it's not too much trouble.
Joe Mamma
This doesn't sound good at all. Not sure about saving it!
No doubt. I wouldn't want to run this gun. I certainly wouldn't want to give the fukktards who wrecked it a chance to "fix" it.
This is the risk of these aftermarket RETARDS jumping in with the latest whizbang nonsense without having a full grasp of what the fukk they are doing.
They SHOULD pay for the replacement.
The only real way to do it right is for someone that has a pile...like 100 barrel extensions. Install them torqued correctly until 1 lines up perfectly or is very close to aligning on the before TDC side. Then turn .001 -.002 off the front of the extension so it will turn a little further to align at the required torque.
I fear all these new companies starting to do Melonite barrels will have these issues unless they torque the extensions after treatment and then drill the gas port and dimple. One company that does Melonite treatment is advising people to drill the alignment pin hole deeper and use a longer pin...That will not work long. The extension is not torqued tight, it will loosen and the barrel will wobble in it. Accuracy will go to crap and all the pin does is hold it loose.
constructor, I don't have as much experience with melonite barrels as you do. So I have 2 questions. What would be wrong with using some type of very strong thread locking compound? Also, wouldn't there be more concerns about incorrect headspace if using a different barrel extension (and retightening) as opposed to just locking down the original barrel extension in the exact same place?
Joe Mamma
Here is some more info on the Melonite process. http://www.customar15.net/ar-15-faq/what-is-melonite/
http://www.customar15.net/ar-15-faq/are-all-melonite-barrels-equal/
constructor
06-11-14, 10:15
constructor, I don't have as much experience with melonite barrels as you do. So I have 2 questions. What would be wrong with using some type of very strong thread locking compound? Also, wouldn't there be more concerns about incorrect headspace if using a different barrel extension (and retightening) as opposed to just locking down the original barrel extension in the exact same place?
Joe Mamma
The difference between the go and no-go is .006 If he has to take off .001-.002 on the front of the extension the headspace should still be ok, especially after shooting and mating the bolt to the extension lugs(compression). Most extensions are held fairly close tolerance. When we machine them I only allow +- .001". If he can get some amount of torque when aligned then it may be possible to use a strong industrial strength thread locker and it hold. If the torque is like 10lbs when aligned I don't think it would work. He broke it loose when working on the muzzle device, couldn't have been much on it.
It may be worth a try, if it comes loose again or accuracy goes out then window then pull it apart and fix it the correct way.
BTW, I know a few custom shops making high end barrels that put very little torque on the extensions. 10 years ago when I was on the road I had a few made, they loosened up after 20 shots and accuracy went from under 3/4" to 4"+. It is near impossible to use a handheld torque wrench and a vice with alum barrel jaws and torque them to 80lbs plus. We have 60lb round part vices and use impact wrenches to torque them on.
...the barrel extension has come loose.
Is there a way to fix this i.e. who can I send this to for fixing?
Contact member opsoff1. He has a method to install extensions on barrels with existing gas ports and may be able to help you
pathfinderheli
06-11-14, 12:48
Thanks for all the replies. BCM actually said they would take a look at it. I don't expect them to replace anything as it seems the issue came from the Melonite process. It's awesome that they would even consider it after all the aftermarket hands have touched it.... I've called the company that melonited the barrel but haven't heard anything back yet. Will keep you all posted.
constructor
06-12-14, 08:19
Thanks for all the replies. BCM actually said they would take a look at it. I don't expect them to replace anything as it seems the issue came from the Melonite process. It's awesome that they would even consider it after all the aftermarket hands have touched it.... I've called the company that melonited the barrel but haven't heard anything back yet. Will keep you all posted.
You're right. I'm sure the company that made the barrel torqued it correctly so it's not BCMs fault. The company that Melonited it should have told you or warned you it may come loose due to the heat causing the parts to expand and shrink at a different rate.
pathfinderheli
06-20-14, 07:54
So here is an update...
I sent this to a forum member here that offered to help. Here is what he did:
"I knurled the shoulder and faced it back. Degreased everything and re-installed the extension. Torqued to 60ft-lbs and rechecked the headspace - right on. 1.464" . The extension was also installed with a thread locker - high strength (Loctite 640) which is actually for sleeve retention - works VERY good on bbl extensions. Before I did all this - the bbl was set up in the milling machine and I indexed off the gas port with gauge pins - this was then transferred with a spotting drill to create an index mark at the shoulder - you'll see it right in front of the index pin. this allows me to align the index pin virtually dead on. This bbl should be all set - enjoy."
Barrel is back installed and plan to shoot it this week...
Thanks for everyone who helped out with suggestions and thanks to Iraqgunz for reopening the thread!!!!
Who did the melonite? I'm not sure I agree with it being the treater's fault unless they genuinely should have known better. If it were a commercial ship it in we'll treat it type place, they probably didn't even look at the barrel twice or understand how it was assembled.
So here is an update...
I sent this to a forum member here that offered to help. Here is what he did:
"I knurled the shoulder and faced it back. Degreased everything and re-installed the extension. Torqued to 60ft-lbs and rechecked the headspace - right on. 1.464" . The extension was also installed with a thread locker - high strength (Loctite 640) which is actually for sleeve retention - works VERY good on bbl extensions. Before I did all this - the bbl was set up in the milling machine and I indexed off the gas port with gauge pins - this was then transferred with a spotting drill to create an index mark at the shoulder - you'll see it right in front of the index pin. this allows me to align the index pin virtually dead on. This bbl should be all set - enjoy."
Barrel is back installed and plan to shoot it this week...
Thanks for everyone who helped out with suggestions and thanks to Iraqgunz for reopening the thread!!!!
Aren't extensions supposed to be torqued to 200 ft/lbs?
Who did the melonite? I'm not sure I agree with it being the treater's fault unless they genuinely should have known better. If it were a commercial ship it in we'll treat it type place, they probably didn't even look at the barrel twice or understand how it was assembled.
I disagree. They should know better. It is a service provider's responsibility to know the intricacies of their craft. Assembled/torqued parts are not exclusive to weapons.
I recently set out to change a muzzle device and put it on a reaction rod rather than fool with the vise. The MD was mounted using a crush washer and I guessed torqued to 30# max. I barely leaned on the wrench and the barrel broke free from the extension! Melonite barrel and ext. I cleaned everything up and torqued to 50# with red loctite. Chucked up in lathe to confirm pin and port index. All is well. If the head space was right to begin with you aren't going to change it. I'll admit being lucky everything line up. If it hadn't I would have trashed the barrel.
So here is an update...
I sent this to a forum member here that offered to help. Here is what he did:
"I knurled the shoulder and faced it back. Degreased everything and re-installed the extension. Torqued to 60ft-lbs and rechecked the headspace - right on. 1.464" . The extension was also installed with a thread locker - high strength (Loctite 640) which is actually for sleeve retention - works VERY good on bbl extensions. Before I did all this - the bbl was set up in the milling machine and I indexed off the gas port with gauge pins - this was then transferred with a spotting drill to create an index mark at the shoulder - you'll see it right in front of the index pin. this allows me to align the index pin virtually dead on. This bbl should be all set - enjoy."
Barrel is back installed and plan to shoot it this week...
Thanks for everyone who helped out with suggestions and thanks to Iraqgunz for reopening the thread!!!!Aren't extensions supposed to be torqued to 200 ft/lbs?
Off of the top of my head, I'm not exactly sure what the torque should be. But it is normally much higher than 60 ft-lbs. However, this is not a normal situation. With the Loctite 640 and 60 ft-lbs, it should work fine. The guy indexed off of the gas port, which is also not normal to do, but it was the right thing to do in this situation.
If I were a betting man, I'd bet everything will work out fine with this barrel/barrel extension.
I recently set out to change a muzzle device and put it on a reaction rod rather than fool with the vise. The MD was mounted using a crush washer and I guessed torqued to 30# max. I barely leaned on the wrench and the barrel broke free from the extension! Melonite barrel and ext. I cleaned everything up and torqued to 50# with red loctite. Chucked up in lathe to confirm pin and port index. All is well. If the head space was right to begin with you aren't going to change it. I'll admit being lucky everything line up. If it hadn't I would have trashed the barrel.
I'm curious. Did you buy the barrel already melonited or did you have it melonnited after you bought it (from somewhere else).
Joe Mamma
Off of the top of my head, I'm not exactly sure what the torque should be. But it is normally much higher than 60 ft-lbs. However, this is not a normal situation. With the Loctite 640 and 60 ft-lbs, it should work fine. The guy indexed off of the gas port, which is also not normal to do, but it was the right thing to do in this situation.
If I were a betting man, I'd bet everything will work out fine with this barrel/barrel extension.
I'm curious. Did you buy the barrel already melonited or did you have it melonnited after you bought it (from somewhere else).
Joe Mamma
Factory assembled upper.
Off of the top of my head, I'm not exactly sure what the torque should be. But it is normally much higher than 60 ft-lbs.
If I recall correctly, Harrison at ARP torques his extensions to 150 lbs-ft using an impact wrench since it is difficult to clamp the barrel with enough force and tighten with a standard wrench. Of course, he also has the luxury of doing this PRIOR to drilling the gas port and the hole for the index pin.
If I recall correctly, Harrison at ARP torques his extensions to 150 lbs-ft using an impact wrench since it is difficult to clamp the barrel with enough force and tighten with a standard wrench. Of course, he also has the luxury of doing this PRIOR to drilling the gas port and the hole for the index pin.
Do you know if he melonites before or after the barrel extension is added?
IIRC, he stated doing them before, in the old thread. I'm not sure if he treats his barrel extensions too.
IIRC, he stated doing them before, in the old thread. I'm not sure if he treats his barrel extensions too.
I have one of his melonited stainless barrels and the extension is melonited along with the barrel. Once the barrel/extension is melonited, THEN he pulls the extension, cleans up the threads and torques, followed by drilling the gas port and the hole for the indexing pin. At least, that's the way I believe it was related to me. The meloniting process and the high heat involved is what loosens up the extension.
Thanks. That confirms it. He probably does them separately though. Doesn't make much sense doing them together, only to take them apart again, esp since theyre not torqued and set up to be pinned yet anyway.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.