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Discussion Starter · #1 ·
The frustration has begun!

I was on Atlantic's website last Monday and saw they had a HK MP5SD clone in stock ... I was on their list for 6+ months to be notified but never got an email ... anyway I jumped and put it on plastic.



Don't be deceived, the suppressor isn't actually attached ... I set it up and took the picture to give myself hope!

It came in Thursday, I took my registered sear/trigger pack and favorite suppressor (just like the website says) and went to pick it up ... the website says the barrel has an 18x1 thread pitch ... which was perfect as I already had an 18x1 adapter for my Octane which I use on my Scorpion EVO ... I loaded up 6 mags with various ammo's and went to my dealer to pick it up.

Obviously I should have done a bit more research.

My registered sear trigger pack and stock fit, but the can wouldn't screw on; at first I thought there was something wrong with the barrel because my "Favorite Suppressor" WONT FIT ... then I got home and it turns out these are made like the original MP5SD-N ... the threads are at the base of the barrel ... then the 5+" of barrel is in front of that ... meaning that your suppressor has to slip over and down the 5 inches of barrel before it can tighten down ... which also mean's my "Favorite Suppressor" WILL NOT FIT!!!

I know ... probably no one here is surprised.

Except the top rivet for the sling clip is kinda mashed, it is really nice! The welds are nice and tidy ... the rear sight welds are just nice and it seems to be on straight so, I'm pretty happy ... but I'm not totally sure because ... you know ... I spent almost $1800 on a gun I can't shoot because my "Favorite Suppressor" WONT FIT ... Lastly I'd have opted for a dull satin finish, over the shiny finish ... but it is a nice finish.

I just can't get over the fact that the website doesn't say to use your favorite MP5SD-N suppressor ... maybe I'm just stupid but when all the info says YOUR FAVORITE SUPPRESSOR with a 18x1 thread, I just assumed mine would fit ... well I guess that makes me an ASS!

So ... rant off.

Does anyone have a link to somewhere I can find a fake suppressor?
Atlantic's site says RDTS.com offers one ... but I'm not having much luck.

I hope to con my buddy with a machine shop to make an adapter for my Octane 45 ... so I can use my favorite suppressor ... eventually as he doesn't get in a hurry about anything I need.

And, on that note ... if anyone that has a suggestion for a proprietary MP5SD suppressor, that would be appreciated, even though it may be 9-10 months or maybe a year before my paperwork can get through the Form 3 and 4 processes ... unless the HPA passes!

TIA
 

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Kimberkid, you will need a proprietary type of suppressor, not your typical baffle stack or monocore suppressor. There's porting on MP5SD barrels that are meant to bleed off gasses reducing supersonic speed ammo to subsonic. The suppressor has an initial chamber that collects the bleeded off gases, then the bullet passes through a series of baffles like you would find in your Octane.

I got an Omega, and my faux suppressor I got from TitleIIArms.

I have purchased a TPM SD suppressor for my SD.
 

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Discussion Starter · #8 ·
This.

You spent ~$30k on a registered sear pack without understanding how an SD works and are now complaining about an extra $400 for the proper can?
No ... I spent 12K on a sear pack, years ago. I have SBR'd clone's in MP5, 51, 52 and 53; an SD has always been on my "want list" but until I saw one for sale it didn't speak to me.

I understand how a real HK SD works, but I'm 60 years old and I still took a website at its word ... I'm pissed at myself for not doing more research before I laid down my plastic. I don't care about the $400 for the can but the 6-10 month wait on the paperwork has me a bit pissed as I was expecting to use my current can ... what I actually thought was it had a 3-4" barrel then threaded 18x1 ... which would make sense if you take the ad to be true.

I've come up with an idea for my machinist to maybe use a 3-lug adapter as part of an adapter for my Octane suppressor so I don't have to wait or go out and buy another suppressor.

I'm no newbie.


Here is one option:
MP5 3 LUG LIGHT MODEL
Or you can make a post in the Want to Buy section of the forum. I found one that way. It will be for sale once my suppressor stamp comes in. The Form 3 isn't approved yet so it's going to be a while. (I went with TPM). Lots of good information on the RCM and TPM cans here
Thanks for the links ... and suggestions from everyone!
 

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You have me really curious on the design of the adapter for your suppressor... with a barrel length like this, which isn't three lug obviously, and then the ports in the one end of the barrel, that will be quite an interesting project maybe?

Microphone Flashlight
 

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Dumb question but... based on what you have written, and your not appearing to be aware that the SD takes an entirely different type suppressor altogether, you do know what the SD barrel looks like and how the SD suppressor works with it right? And that its not like the barrel on other MP5's and other guns? Forgive me if I am stating things you already know, but I am kind of thinking you need to do some more research on the SD and how it all works.
 

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No ... I spent 12K on a sear pack, years ago. I have SBR'd clone's in MP5, 51, 52 and 53; an SD has always been on my "want list" but until I saw one for sale it didn't speak to me.

I understand how a real HK SD works, but I'm 60 years old and I still took a website at its word ... I'm pissed at myself for not doing more research before I laid down my plastic. I don't care about the $400 for the can but the 6-10 month wait on the paperwork has me a bit pissed as I was expecting to use my current can ... what I actually thought was it had a 3-4" barrel then threaded 18x1 ... which would make sense if you take the ad to be true.

I've come up with an idea for my machinist to maybe use a 3-lug adapter as part of an adapter for my Octane suppressor so I don't have to wait or go out and buy another suppressor.

I'm no newbie.




Thanks for the links ... and suggestions from everyone!
I had to comment on this. Your hosts look just like mine. And I understand about the wait. Hopefully the Hearing protection act will be passed as law soon. You might get a suppressor purchase started through a dealer and not start the paper work. My dealer is suggesting this because if the law gets past there will be an immediate shortage of supressors. Again love your hosts. And good luck.

Sent from my Pixel XL using Tapatalk
 

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Discussion Starter · #13 · (Edited)
You have me really curious on the design of the adapter for your suppressor... with a barrel length like this, which isn't three lug obviously, and then the ports in the one end of the barrel, that will be quite an interesting project maybe?

View attachment 99410
I'd think an adapter for a existing suppressor would be quite easy to make; one end would just have to screw on the threads at the base of the barrel, an extension with a barrel support and vents in it to release the gasses from the vents at the base of the barrel, then screw your existing suppressor on the adapter like the 3-lug adapter does; you could even have another barrel support near the end the adapter to ensure the bullet exit is in line with the baffles so there are no baffle strikes ... my Octane is full-otto rated and works great on my MP5 clone with the 3-lug adapter ... so is there any reason why an SD adapter couldn't be made?

I'm probably giving away my million dollar idea ... but if someone does run with it, maybe they'll let me do some testing and get a free sample!
 

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There is another option. You could have your pistol built into a "faux SD". Does your "Favorite Suppressor" have a 3-lug adapter? If so, you could send your SD to a smith. They could pull the SD barrel and install a "K" barrel. A locking piece for a "K" needs to replace the SD LP. This could be done to shoot it right now. Keep it that way or you could get the SD can and convert it back.

Scott
 

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I have a friend with a two stamp 9mm AR that is set up exactly at what you are describing Scott. The barrel is recessed back from the front of the handguards a couple inches. The can goes into the handguards and the three lug takes over.

It works great on that gun (straight blowback) and should work in this case too.
 

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Barrel is designed to slip into the suppressor about 4 inches or so. You need a different suppressor and you should be good. I am building one for a customer right now. Bought an RCM can for it, looks and fits great and the price is very competitive. I plan to build more of these.
 

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I'd think an adapter for a existing suppressor would be quite easy to make; one end would just have to screw on the threads at the base of the barrel, an extension with a barrel support and vents in it to release the gasses from the vents at the base of the barrel, then screw your existing suppressor on the adapter like the 3-lug adapter does; you could even have another barrel support near the end the adapter to ensure the bullet exit is in line with the baffles so there are no baffle strikes ... my Octane is full-otto rated and works great on my MP5 clone with the 3-lug adapter ... so is there any reason why an SD adapter couldn't be made?
There are a couple of problems I see with this idea. First, the gas vented by the barrel is fairly high pressure and the vents are close enough to the chamber that some of the powder is still burning. Where is this vented high pressure burning gas going to go? Under the hand guard would not be good for the hand guard or the support hand. That is why there is such a large sealed blast chamber at the back of a typical SD can. The gas moves faster than the bullet. So in a standard SD can the gas dumped into the blast chamber starts out through the barrel end support with vents in it that dumps that blast chamber gas into the baffle area before the bullet clears the end of the barrel.

Part of why the SD is quiet is the volume of the can giving the vented gas somewhere to go. So with the SD adapter you'd be using a smaller volume can. All of that would make the SD that much more nose heavy. But even more importantly, would this adapter reduce the report of the firearm itself? I don't know, I'm asking. And the Tech Branch has relaxed the earlier stance that any suppressor parts are a suppressor themselves and has allowed the owner to have multiple mounts. So how would the Tech Branch view this device?

Scott
 

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Discussion Starter · #19 · (Edited)
There are a couple of problems I see with this idea. First, the gas vented by the barrel is fairly high pressure and the vents are close enough to the chamber that some of the powder is still burning. Where is this vented high pressure burning gas going to go? Under the hand guard would not be good for the hand guard or the support hand. That is why there is such a large sealed blast chamber at the back of a typical SD can. The gas moves faster than the bullet. So in a standard SD can the gas dumped into the blast chamber starts out through the barrel end support with vents in it that dumps that blast chamber gas into the baffle area before the bullet clears the end of the barrel.

Part of why the SD is quiet is the volume of the can giving the vented gas somewhere to go. So with the SD adapter you'd be using a smaller volume can. All of that would make the SD that much more nose heavy. But even more importantly, would this adapter reduce the report of the firearm itself? I don't know, I'm asking. And the Tech Branch has relaxed the earlier stance that any suppressor parts are a suppressor themselves and has allowed the owner to have multiple mounts. So how would the Tech Branch view this device?

Scott
Thanks for asking Scott ... my theory is that the gasses would dump into the suppressor, actually into the adapter, just like a SD suppressor, you would have a barrel support just in front of the bleed-off ports, or maybe at the end of the barrel; that support would be vented ... to give the gas an escape route and that chamber would be would be 4" or so just as a SD suppressor would. Then, just as with the 3-lug adapter the baffle stack wouldn't quite touch the barrel but would be centered with the bore, just as a SD suppressor is; so unless you had an actual suppressor screwed on the end of the adapter, there would be no suppression at all and all the escaping gas would and subsequent report would exit through the adapter or end of the barrel ... For what ever its worth, my thoughts are, that if there was any suppression from the ventilated barrel support and would be as negligible as that of what you get with the Noveske Flaming Pig (or knock-off; which in my mind is a single baffle suppressor) ... but Noveske presented it to the BTAFE as a flash "arrestor" (if that's a word) and it was approved.

Thoughts?
 

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Discussion Starter · #20 ·
There is another option. You could have your pistol built into a "faux SD". Does your "Favorite Suppressor" have a 3-lug adapter? If so, you could send your SD to a smith. They could pull the SD barrel and install a "K" barrel. A locking piece for a "K" needs to replace the SD LP. This could be done to shoot it right now. Keep it that way or you could get the SD can and convert it back.

Scott
A "faux SD" is really what I thought I was getting, except I thought the barrel was threaded ... We are talking clones here, and it was only $1800, so I really wasn't expecting a true clone when the ad said I could use my favorite suppressor! Now that I've had some time to come to terms with what I've got, I'm happy about it and glad it wasn't the "faux SD" ... I only hope that when I get a suppressor (real or fake) that it is centered in the SD frame, doesn't rub on my charge handle or any of the other problems I've heard of ... its bad enough that a rivet on the mag-well sling mount is mashed ... it looks like the rivet setter wasn't quite centered on the rivet and made a crease down the middle of it ... if it was a queen or "real" HK I'd complain about it, but I bought it to shoot ... as I said before, I don't abuse them but they are tools, not show pieces.

You mentioned getting a shorter barrel but at this point I'm not going that route ... I bought a carbine handguard for my Scorpion EVO pistol and I've put short barrels with long handguards on couple AR uppers for my M16 & SBR'd lowers ... a 16" AR57 upper I cut the barrel down to 8" and had it re-threaded ... I went with an 8" barrel so I could use either my suppressor or a long AR flash hider to get past the hand guard, either way its still only about 13" with the barrel ... the other is a 300BO which has an 8" barrel and the handguard covers about 1/3 to 1/2 of the suppressor. That's fine for those guns ... but this is an SD and since its not a faux SD, I'll not make it one.


Barrel is designed to slip into the suppressor about 4 inches or so. You need a different suppressor and you should be good. I am building one for a customer right now. Bought an RCM can for it, looks and fits great and the price is very competitive. I plan to build more of these.
I'd like to hear more about this project, and see some pictures ... you can message me or I believe my email is in my profile.
 
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