BCM barrel not mating with AAC Blackout 51t flash hider? - Page 1

AR-15 » AR Discussions

AR Sponsor:

[ARCHIVED THREAD] - BCM barrel not mating with AAC Blackout 51t flash hider?

Posted: 4/27/2017 12:18:22 AM EDT

Just got my BCM 14.5" Forged barrel in the mail today and went to throw on my AAC Blackout 51t flash hider on there and the opening of the flash hider isn't big enough to overlap the barrel and the threads will not even touch each other. The barrel is a standard gov't profile so I'm not sure how this is not a common issue, however upon searching for the issue, I could not find anyone having the same problem. Has anyone here experienced this? Here's the links to the two specific items I'm putting together.

Barrel: https://www.bravocompanyusa.com/BCM-BFH-14-5-Mid-Length-Barrel-Stripped-p/bcm-brl-s-mid-14%20bfh.htm

Flash Hider: http://www.advanced-armament.com/BLACKOUT-51T-Flash-Hider_p_447.html (1/2x28 model)

Posted: 4/27/2017 12:44:33 AM EDT

[#1]

My first thought would be to confirm you do have the correct FH. My SDN-6 came with a 762 FH in the box. If you bought it separately or used, it may have been swapped in the blister pack, or the seller made a mistake.

Do you have a throwaway A2 FH to thread onto the barrel to confirm it's correct?

Posted: 4/27/2017 1:50:10 AM EDT

[#2]

Yeah I wonder if you have the right thread pitch.

Posted: 4/27/2017 5:24:11 AM EDT

[#3]

Does the barrel say 5.56 on it? It sounds like a 300blk barrel w/ a 5.56 flash hider.

Posted: 4/27/2017 7:35:51 AM EDT

[#4]

Quote History

Quoted:
My first thought would be to confirm you do have the correct FH. My SDN-6 came with a 762 FH in the box. If you bought it separately or used, it may have been swapped in the blister pack, or the seller made a mistake.

Do you have a throwaway A2 FH to thread onto the barrel to confirm it's correct?

View Quote

I did test another A2 flash hider that doesn't have the socket like the AAC does and it goes right on. This particular flash hider does have a deep socket model which is meant for larger barrels, but it only comes in the 7.62 (5/8x24) thread pitch. So one would assume that their ONLY 5.56 model that you can select would thread over a standard size 5.56 barrel.

Posted: 4/27/2017 7:37:10 AM EDT

[#5]

Quote History

Quoted:
Yeah I wonder if you have the right thread pitch.

View Quote

My other flash hider threaded on there so it's definitely the right thread pitch. The issue is that the threads never even make it to each other. The socket on the flash hider isn't large enough to go around the shoulder of the barrel, so the threads never touch.

Posted: 4/27/2017 7:38:31 AM EDT

[#6]

Quote History

Quoted:
Does the barrel say 5.56 on it? It sounds like a 300blk barrel w/ a 5.56 flash hider.

View Quote

Barrel is definitely stamped 5.56. Unless it's a 300blk barrel stamped 5.56 but there's nothing I can do about that lol.

Posted: 4/27/2017 8:28:28 AM EDT

[#7]

What is the measured diameter of the muzzle end of the barrel? What is the measured opening of the muzzle device?

Posted: 4/27/2017 8:44:48 AM EDT

[#8]

Quote History

Quoted:

My other flash hider threaded on there so it's definitely the right thread pitch. The issue is that the threads never even make it to each other. The socket on the flash hider isn't large enough to go around the shoulder of the barrel, so the threads never touch.

View Quote

Is this one of the over the barrel mounts from AAC? The ones that sleeve over the end of the barrel before threading on? If so, I believe AAC had a note on their site at one time that said they only worked with certain barrel diameters. Your barrel may just be too large.

ETA: Just post a pic showing us what the problem is. They'll clear things up immediately.

Posted: 4/27/2017 8:54:57 AM EDT

[#9]

Quote History

Quoted:

Is this one of the over the barrel mounts from AAC? The ones that sleeve over the end of the barrel before threading on? If so, I believe AAC had a note on their site at one time that said they only worked with certain barrel diameters. Your barrel may just be too large.

ETA: Just post a pic showing us what the problem is. They'll clear things up immediately.

View Quote

This is what he's referring to, he has a recessed aac mount and needs a flush mount. His won't clear the barrel shoulder diameter.

Posted: 4/27/2017 8:58:30 AM EDT

[#10]

Quote History

Quoted:
This is what he's referring to, he has a recessed aac mount and needs a flush mount. His won't clear the barrel shoulder diameter.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

Is this one of the over the barrel mounts from AAC? The ones that sleeve over the end of the barrel before threading on? If so, I believe AAC had a note on their site at one time that said they only worked with certain barrel diameters. Your barrel may just be too large.

ETA: Just post a pic showing us what the problem is. They'll clear things up immediately.

This is what he's referring to, he has a recessed aac mount and needs a flush mount. His won't clear the barrel shoulder diameter.

That's what I figured. It should be obvious to him what's wrong. Not sure what the problem is.

Posted: 4/27/2017 12:33:21 PM EDT

[#11]

Quote History

Quoted:
That's what I figured. It should be obvious to him what's wrong. Not sure what the problem is.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

Is this one of the over the barrel mounts from AAC? The ones that sleeve over the end of the barrel before threading on? If so, I believe AAC had a note on their site at one time that said they only worked with certain barrel diameters. Your barrel may just be too large.

ETA: Just post a pic showing us what the problem is. They'll clear things up immediately.

This is what he's referring to, he has a recessed aac mount and needs a flush mount. His won't clear the barrel shoulder diameter.

That's what I figured. It should be obvious to him what's wrong. Not sure what the problem is.

It is obvious to me what's wrong, but what I'm trying to find out here is if anyone else has run into this issue as well. It would seem if it's their only 5.56 offering then it would work with all standard 5.56 barrels as this is a standard gov't profile barrel.

There is a note on the site about it only working with up to a certain size barrel, but the larger socket is only offered in 7.62 so I made an assumption that the issue is only run into with those barrels, not 5.56.

I just called and talked to someone at AAC and he said he has no idea why it won't go over the barrel and it must just be an issue of BCM making their barrels slightly larger than everyone else. So I guess what I am going to have to do is have the guy who is pinning it for me just mill it out a slight bit so that it will go over the barrel shoulder.

Posted: 4/27/2017 12:38:45 PM EDT

[#12]

Buy Colt.

Posted: 4/27/2017 12:50:19 PM EDT

[#13]

Quote History

Quoted:
Buy Colt.

View Quote

Colt only makes a standard flash hider, I wanted a suppressor mounting flash hider.

Posted: 4/27/2017 12:52:57 PM EDT

[#14]

Quote History

Quoted:

Colt only makes a standard flash hider, I wanted a suppressor mounting flash hider.

View Quote

Colt barrel.

Posted: 4/27/2017 12:53:52 PM EDT

[#15]

Quote History

Quoted:
Colt only makes a standard flash hider, I wanted a suppressor mounting flash hider.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Buy Colt.

Colt only makes a standard flash hider, I wanted a suppressor mounting flash hider.

Ignore him. That's the only thing he ever posts about is Colt. He never offers up anything insightful.

Posted: 4/27/2017 12:55:39 PM EDT

[#16]

Quote History

Quoted:
It is obvious to me what's wrong, but what I'm trying to find out here is if anyone else has run into this issue as well. It would seem if it's their only 5.56 offering then it would work with all standard 5.56 barrels as this is a standard gov't profile barrel.

There is a note on the site about it only working with up to a certain size barrel, but the larger socket is only offered in 7.62 so I made an assumption that the issue is only run into with those barrels, not 5.56.

I just called and talked to someone at AAC and he said he has no idea why it won't go over the barrel and it must just be an issue of BCM making their barrels slightly larger than everyone else. So I guess what I am going to have to do is have the guy who is pinning it for me just mill it out a slight bit so that it will go over the barrel shoulder.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

Is this one of the over the barrel mounts from AAC? The ones that sleeve over the end of the barrel before threading on? If so, I believe AAC had a note on their site at one time that said they only worked with certain barrel diameters. Your barrel may just be too large.

ETA: Just post a pic showing us what the problem is. They'll clear things up immediately.

This is what he's referring to, he has a recessed aac mount and needs a flush mount. His won't clear the barrel shoulder diameter.

That's what I figured. It should be obvious to him what's wrong. Not sure what the problem is.

It is obvious to me what's wrong, but what I'm trying to find out here is if anyone else has run into this issue as well. It would seem if it's their only 5.56 offering then it would work with all standard 5.56 barrels as this is a standard gov't profile barrel.

There is a note on the site about it only working with up to a certain size barrel, but the larger socket is only offered in 7.62 so I made an assumption that the issue is only run into with those barrels, not 5.56.

I just called and talked to someone at AAC and he said he has no idea why it won't go over the barrel and it must just be an issue of BCM making their barrels slightly larger than everyone else. So I guess what I am going to have to do is have the guy who is pinning it for me just mill it out a slight bit so that it will go over the barrel shoulder.

That's an assumption I wouldn't have made without doing some research beforehand. Would've saved you the deal you're in now with incompatible parts.

Posted: 4/27/2017 1:08:39 PM EDT

[#17]

Quote History

Quoted:

It is obvious to me what's wrong, but what I'm trying to find out here is if anyone else has run into this issue as well. It would seem if it's their only 5.56 offering then it would work with all standard 5.56 barrels as this is a standard gov't profile barrel.

There is a note on the site about it only working with up to a certain size barrel, but the larger socket is only offered in 7.62 so I made an assumption that the issue is only run into with those barrels, not 5.56.

I just called and talked to someone at AAC and he said he has no idea why it won't go over the barrel and it must just be an issue of BCM making their barrels slightly larger than everyone else. So I guess what I am going to have to do is have the guy who is pinning it for me just mill it out a slight bit so that it will go over the barrel shoulder.

View Quote

I could have sworn they had a flush 556 hider, but maybe not.

Posted: 4/27/2017 2:23:41 PM EDT

[#18]

Quote History

Quoted:

I could have sworn they had a flush 556 hider, but maybe not.

View Quote

They do, but not one that has the suppressor quick mount.

Posted: 4/27/2017 2:32:16 PM EDT

[#19]

So I do not know that I have solved my issue with the sleeve part going around the shoulder of the barrel, but I have uncovered an entirely new issue. I was looking closer at the flash hider and noticed that the distance from the end of the flash hider to where the threads starts is not far at all, and with the length of the threaded portion of the barrel, they should make contact with each other long before the end of the flash hider hits the shoulder of the barrel. What did I find out? Apparently I was sent the entirely wrong thread size flash hider because the barrel threads are slipping completely through the flash hider threads. I'm not sure what thread pitch it is because it would not thread on my .308 (5/8x24) so I assume it is something between the two calibers. I contacted Buds Gun Shop which is who I ordered the flash hider from and that was the absolute worst customer service experience in my life, but I'll save that for another post. I then inspected the packaging it came in and on the back where they mark which specific model/caliber/thread pitch it is, they have the "5.56 1/2x28" so Buds deferred me to AAC. As I was on the phone with AAC I also noticed that the packaging was for a "Brakeout 2.0 51t" compensator, but what was in the packaging was a Blackout 51t flash hider. So now that that's figured out, AAC is sending me the correct part. I still have a feeling I will have to mill out the flash hider once I get it to have it go over the barrel correctly, but I'll deal with that once it gets here.

Posted: 4/27/2017 2:46:01 PM EDT

[#20]

Quote History

Quoted:
So I do not know that I have solved my issue with the sleeve part going around the shoulder of the barrel, but I have uncovered an entirely new issue. I was looking closer at the flash hider and noticed that the distance from the end of the flash hider to where the threads starts is not far at all, and with the length of the threaded portion of the barrel, they should make contact with each other long before the end of the flash hider hits the shoulder of the barrel. What did I find out? Apparently I was sent the entirely wrong thread size flash hider because the barrel threads are slipping completely through the flash hider threads. I'm not sure what thread pitch it is because it would not thread on my .308 (5/8x24) so I assume it is something between the two calibers. I contacted Buds Gun Shop which is who I ordered the flash hider from and that was the absolute worst customer service experience in my life, but I'll save that for another post. I then inspected the packaging it came in and on the back where they mark which specific model/caliber/thread pitch it is, they have the "5.56 1/2x28" so Buds deferred me to AAC. As I was on the phone with AAC I also noticed that the packaging was for a "Brakeout 2.0 51t" compensator, but what was in the packaging was a Blackout 51t flash hider. So now that that's figured out, AAC is sending me the correct part. I still have a feeling I will have to mill out the flash hider once I get it to have it go over the barrel correctly, but I'll deal with that once it gets here.

View Quote

How did you determine the barrel threads slip right through the flash hider threads if you said earlier that it wouldn't fit over the barrel shoulder? Maybe I'm missing something...

Posted: 4/27/2017 4:37:43 PM EDT

[#21]

Quote History

Quoted:

How did you determine the barrel threads slip right through the flash hider threads if you said earlier that it wouldn't fit over the barrel shoulder? Maybe I'm missing something...

View Quote

So from the outer edge of the flash hider to where the threads start is roughly 1/4". The threaded portion of the barrel is roughly 3/4"-1". Therefore the barrel should go about 1/4" into the flash hider and then the threads should make contact with each other and be able to thread 1/2"-3/4" before the 2 shoulders ever meet. I didn't pay attention to this the first time and just thought the shoulders were hitting before the threads. I looked at it closer and you can see the barrel threads slipping straight through the flash hider threads.

Posted: 4/27/2017 4:42:50 PM EDT

[#22]

Quote History

Quoted:

So from the outer edge of the flash hider to where the threads start is roughly 1/4". The threaded portion of the barrel is roughly 3/4"-1". Therefore the barrel should go about 1/4" into the flash hider and then the threads should make contact with each other and be able to thread 1/2"-3/4" before the 2 shoulders ever meet. I didn't pay attention to this the first time and just thought the shoulders were hitting before the threads. I looked at it closer and you can see the barrel threads slipping straight through the flash hider threads.

View Quote

Okay, I gotcha now. Good on AAC for taking care of you.

Posted: 4/27/2017 9:56:36 PM EDT

[#23]

Awesome, I've had good experiences with AACs customer service, have a few of their suppressors.

Posted: 4/27/2017 10:27:21 PM EDT

[#24]

Quote History

Quoted:
Awesome, I've had good experiences with AACs customer service, have a few of their suppressors.

View Quote

Well Buds on the other hand, before we realized it was AAC who packaged the wrong part but we had established it was not the correct thread size, told me that because their site did not specifically say "1/2x28" (despite listing the specific part number for 1/2x28) they could not return the part because A. I had already opened it, and B. Because for all they knew I did get the right part because their listing did not say which specific part it was.

Posted: 5/5/2017 7:46:33 AM EDT

[#25]

Plot twist! So the rep who I've been dealing with at AAC sends me an email the other day asking again where I got the flash hider from. The reason he was asking was because he said that after he and their R&D guys looked it over, they determined that it was a knock-off, fake version of their flash hider. So not only did Buds send me the wrong sized flash hider in the wrong product packaging...the product that I did get wasn't even legit! Buyer beware for sure!

Posted: 5/5/2017 8:20:38 AM EDT

[#26]

Quote History

Quoted:
Plot twist! So the rep who I've been dealing with at AAC sends me an email the other day asking again where I got the flash hider from. The reason he was asking was because he said that after he and their R&D guys looked it over, they determined that it was a knock-off, fake version of their flash hider. So not only did Buds send me the wrong sized flash hider in the wrong product packaging...the product that I did get wasn't even legit! Buyer beware for sure!

View Quote

Oh wow! I never would have thought it but it makes sense. I have several and I don't see one being so far out that it wouldn't fit over a BCM barrel.

So have you called Buds? Is AAC calling them? Sucks that you're in the middle of this.

Posted: 5/5/2017 11:50:19 AM EDT

[#27]

So, what happened here? Did an employee somewhere along the line do a switcheroo thinking no one would notice? Or maybe someone had a knock-off, then bought the original and sent the knock-off back as a return?

Posted: 5/5/2017 2:06:11 PM EDT

[#28]

Quote History

Quoted:

So from the outer edge of the flash hider to where the threads start is roughly 1/4". The threaded portion of the barrel is roughly 3/4"-1". Therefore the barrel should go about 1/4" into the flash hider and then the threads should make contact with each other and be able to thread 1/2"-3/4" before the 2 shoulders ever meet. I didn't pay attention to this the first time and just thought the shoulders were hitting before the threads. I looked at it closer and you can see the barrel threads slipping straight through the flash hider threads.

View Quote

Post some damn photos instead of paragraphs.

Posted: 5/5/2017 2:07:48 PM EDT

[#29]

Quote History

Quoted:
Plot twist! So the rep who I've been dealing with at AAC sends me an email the other day asking again where I got the flash hider from. The reason he was asking was because he said that after he and their R&D guys looked it over, they determined that it was a knock-off, fake version of their flash hider. So not only did Buds send me the wrong sized flash hider in the wrong product packaging...the product that I did get wasn't even legit! Buyer beware for sure!

View Quote

Holy shit, LOL! Never would have guessed that. Wow

Posted: 5/5/2017 8:32:19 PM EDT

[#30]

Quote History

Quoted:
Post some damn photos instead of paragraphs.

View Quote

Posted: 5/5/2017 8:45:14 PM EDT

[#31]

For it to bottom out though, the thread diameter on the hider has to be larger than 1/2. That or the threads on the BCM are only a 1/4" long.

Posted: 5/5/2017 8:46:56 PM EDT

[#32]

That FH is all kinds of wrong, probably 5/8 thread.

Posted: 5/5/2017 10:45:43 PM EDT

[#33]

Quote History

Quoted:
That FH is all kinds of wrong, probably 5/8 thread.

View Quote

It's not 5/8 cause I have a .308 that's 5/8 and it's too small to go on it, but too big for the 1/2.

And I called Buds about it and they said they were gonna call the rep I had been dealing with at AAC. Last I talked to him, he hasn't heard from them and so as of yet, Buds has no idea that AAC is taking care of it for me still, yet they have made no attempt to make it right.

Posted: 5/5/2017 10:54:48 PM EDT

[#34]

Quote History

Quoted:
So, what happened here? Did an employee somewhere along the line do a switcheroo thinking no one would notice? Or maybe someone had a knock-off, then bought the original and sent the knock-off back as a return?

View Quote

The rep at AAC seems to think someone purchased a legit one, and returned the fake one. I find that hard to believe though because it still doesn't explain how Buds sent me the correct product (despite being the wrong size) when it was in the packaging for a completely different product.

Posted: 5/6/2017 3:13:28 PM EDT

[#35]

I would guess that it's an airsoft part, in which case you're damn lucky it didn't fit on your threads.

Posted: 5/6/2017 5:22:08 PM EDT

[#36]

AAC makes a version of this flash hider that is deep welled and threaded for an M1A and is .595"-32. I accidently bought one at a local gun store and during the install I quickly realized that dog wasn't going to hunt. Another option to consider.

Posted: 5/7/2017 7:19:54 AM EDT

[#37]

Quote History

Quoted:

It's not 5/8 cause I have a .308 that's 5/8 and it's too small to go on it, but too big for the 1/2.

And I called Buds about it and they said they were gonna call the rep I had been dealing with at AAC. Last I talked to him, he hasn't heard from them and so as of yet, Buds has no idea that AAC is taking care of it for me still, yet they have made no attempt to make it right.

View Quote

I gave up on Buds many years ago.

Great to hear AAC is working with you

Posted: 5/29/2017 1:42:10 AM EDT

[#38]

Find a thread pitch gauge and see what you have, also-measurement of the thread inside diameter will give you a ball park of what the male sides diameter would be minus thread pitch.

I wonder if it really is an air soft setup.

Will your can ratchet on it ok?

[ARCHIVED THREAD] - BCM barrel not mating with AAC Blackout 51t flash hider?

AR-15 » AR Discussions

AR Sponsor:

Warning

Confirm Action

About AR15.COM

Stay Connected

Newsletter

Contact Us