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Discussion Starter #1
I do not want to SBR my PS90 because when you move an SBR across US state lines, you need to inform the ATF/etc.

OTOH, you don't need to inform the ATF when you take a suppressor across state lines.

I want to have minimum length for the rifle without going the SBR route, so I want to get and install a reflex suppressor instead of a conventional suppressor (alternatively, I would like an integral suppressor, but can't find one for the PS90). A reflex suppressor is a suppressor that has much of the volume for the suppressor behind the muzzle of the barrel.

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So the legal issue is, the suppressor is removable, which if I simply thread the end of the PS90 barrel, would make the OAL of the rifle too short. However, without something on the end of the barrel to hold the barrel in place against the action, the rifle will not function. So if I have a flashhider or suppressor mount that extends far enough to make the OAL legal, then I should not run afoul of the ATF - right? Since the 16" barrel by itself cannot function on the rifle without something to hold it in place, the rifle is not an SBR, right?

Clear as mud?
 

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So the legal issue is, the suppressor is removable, which if I simply thread the end of the PS90 barrel, would make the OAL of the rifle too short. However, without something on the end of the barrel to hold the barrel in place against the action, the rifle will not function. So if I have a flashhider or suppressor mount that extends far enough to make the OAL legal, then I should not run afoul of the ATF - right? Since the 16" barrel by itself cannot function on the rifle without something to hold it in place, the rifle is not an SBR, right?

Clear as mud?
For the part of the text I "bolded", either the flash hider or the suppressor would have to be permanently attached to achieve this. OAL is determined without the removable muzzle devices attached. This is why the flash hider is pinned on the PS90.

In case you weren't aware, FN Specialties sells a threaded barrel shroud which will get you to the legal length. Just curious, do you have an over the barrel suppressor picked out?
 

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Discussion Starter #3 (Edited)
For the part of the text I "bolded", either the flash hider or the suppressor would have to be permanently attach to achieve this. OAL is determined without the removable muzzle devices attached. This is why the flash hider is pinned on the PS90.
Yes, if a person could take the flash hider off, the OAL would be shorter than is legally allowed, but then the rifle could not operate either. That is where I am a bit confused - if it can't operate without something on the end of the barrel, then it isn't an "accessory", it is a necessary part of the firearm. Most rifles don't have this constraint. Yes, if the user were allowed to remove the factory flash hider, then they could replace it with a shorter one, making the rifle an SBR, but would it be an SBR without any flash hider at all since it could not operate without a muzzle device?

In case you weren't aware, FN Specialties sells a threaded barrel shroud which will get you to the legal length. Just curious, do you have an over the barrel suppressor picked out?
Thanks.

Until today I was just thinking I would put out feelers to someone like Tornado Tech or Thompson Machine to see if they would take on the task of making an integral suppressor, but I did another search for reflex suppressors and found a couple of manufacturers.

https://amtacsuppressors.com/suppressors/cqb/
https://spikestactical.com/collections/suppressors/lrs-long-reflex-suppressor/

There are probably more.

Alternatively, I was thinking that I could shorten the barrel, then have the suppressor permanently attached to the barrel such that it satisfied the regs/laws regarding OAL. If I did that, then the design of the suppressor would need to be such that the internals could be removes out the front for cleaning. Or there could be a shroud attached permanently to the barrel and the suppressor inserted inside the shroud - IIRC there used to be a product like this, but it is no longer made/sold? Tactical Solutions made something like this for the 10/22 IIRC.
 

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You could always put a buttpad spacer on the PS90 to get the min OAL length requirement. The PS90 is hard to overcome with using a suppressor because you need some sort of shroud to to capture the barrel in the gun. Now you could have someone design you a pinch/clamp mount that would go on the barrel near the receiver to retain the barrel. That would leave your M12 threads at the end of the barrel for you to mount your suppressor to.
 

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Gotcha. So you are essentially talking about an item like the CMMG thread adapter or P90 flash hider (SBR), but with a 16" barrel.

I'll add one additional item for consideration. Jay Wolf from Elite Ammunition discusses on his channel the problems caused by having the longer barrel than the P90's original design, and the stock. I've heard the same from other sources as well. This is covered in the "Primary Stock Failure Point" 1 & 2 below.
https://www.youtube.com/user/EliteAmmunition/videos

I understand why you're looking to go this route. In my case, after evaluating everything including the issues above, I decided to just SBR it to return it's original design, and add a .300 Blackout pistol for travel across State lines. If you're set on no SBR, then I'd personally just permanently attach a suppressor to get to the minimum OAL. It's a high pressure round, so I don't see the need to be able to disassemble & clean the suppressor. The parts are also already available, avoiding the additional cost and hassles incurred with a custom job.
 

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You may have to have the suppressor special made unless you've got one in mind. I think you could have a good gunsmith/machinist modify the full length shroud at both the flash hider end as well as adding in some threads somewhere in the middle/outside of it to screw the suppressor on. Taking the shroud off "gently" is simple, especially in a machinist shop, then you could get to work modifying it. Can't imagine what that little project would cost you. Bet when it was said and done you could buy another gun and suppressor with what it'll cost you. Personally, I'd buy the Imperial shroud and mount the suppressor of your choice.....well that's what I did too on my 16" PS90. Works great.
 

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Discussion Starter #7
I live about 20 miles from TROS and Tornado Tech - halfway between the two as a matter of fact - plus there is a good gunsmith a bit further away who does custom work.

I am leaning towards getting the shroud with the threading on the end, and then going with the reflex suppressor. I don't shoot the rifle that much, as I have plenty of other guns to shoot, but I the PS90 is one that I would like a suppressor on.
 

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I'm curious as to what suppressor you're looking at. Could you post a link? Changing the shroud is easy as long as you have some decent tools and mechanical ability. If you're going to suppress the long barrel I found Elite Ammo's tungsten carrier weight to be a good investment. He has good videos of it and why it's produced. Best of luck and post pics if/when you get it done.
 

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What the heck is a reflex suppressor...are you talking about an OTB setup?

I would just SBR the thing...the ATF notification isn't that big of a deal...
 

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Discussion Starter #10
I'm curious as to what suppressor you're looking at. Could you post a link? Changing the shroud is easy as long as you have some decent tools and mechanical ability. If you're going to suppress the long barrel I found Elite Ammo's tungsten carrier weight to be a good investment. He has good videos of it and why it's produced. Best of luck and post pics if/when you get it done.
I posted some links above
 

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I like the looks
 

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Discussion Starter #14

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https://amtacsuppressors.com/suppressors/fire-ant-22-suppressor/

Weight is 5.75 ounces.

That is on par with other 5.7x28 suppressors

That is an end of barrel design though.

So looking at their over the barrel suppressors, yes, they are heavy.

I would need to find a reflex suppressor that was lightweight.

Good point.
Yea, I was speaking only to their over the barrel ones.....20+ ounces is heavy. I've got a Phantom M2 and at 25 ounces it's a beast, works good for SBR 308s and full auto guns though. Good luck in your search.
 

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Here is a thought on PS90 SBRs. Rather than butcher the normal barrel, consider buying a new receiver like Imperial Arms EFFEN90. The PS90 “upper” is the receiver so you can easily switch “uppers” on the lower stock.

When your Form 1 is returned install a 10” barrel and engrave the receiver. Then you will have both a SBR and a street legal PS90.

www.imperialarmsco.com/product-p/10-0001.htm
 

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Discussion Starter #17
Here is a thought on PS90 SBRs. Rather than butcher the normal barrel, consider buying a new receiver like Imperial Arms EFFEN90. The PS90 “upper” is the receiver so you can easily switch “uppers” on the lower stock.

When your Form 1 is returned install a 10” barrel and engrave the receiver. Then you will have both a SBR and a street legal PS90.

www.imperialarmsco.com/product-p/10-0001.htm
Doesn't solve my desire to take the rifle across state lines with the suppressor without having to deal with the ATF every time I take it with me.

I am now retired (laid off in March) and I intend to start traveling sometime soon. I have a one ton 4x4 with a 12' flatbed that I want to convert to an RV. I want to take some firearms with me. My PS90 & Five Seven are my "get home" firearms (if SHTF and I need to hoof it).

But your idea with a slight mod has merit - as I mentioned, having the suppressor pinned/silver soldered to the barrel could solve the OAL legalities while keeping the weight down (I would assume a titanium suppressor would not add more - on not much more, maybe less - weight to a ~10" barrel than the difference in weight between the 10" and the 16" with flash hider).
 

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It is surprising that reflex suppressors are not more popular.

They are like the bullpup rifle in that you can put the expansion chamber behind the end of he barrel and shorten up the overall length for the same effectiveness suppressor, maybe knock off 3 to 4 inches of length for he same amount of ANTI-BOOM.
 

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Doesn't solve my desire to take the rifle across state lines with the suppressor without having to deal with the ATF every time I take it with me.

I am now retired (laid off in March) and I intend to start traveling sometime soon. I have a one ton 4x4 with a 12' flatbed that I want to convert to an RV. I want to take some firearms with me. My PS90 & Five Seven are my "get home" firearms (if SHTF and I need to hoof it).

But your idea with a slight mod has merit - as I mentioned, having the suppressor pinned/silver soldered to the barrel could solve the OAL legalities while keeping the weight down (I would assume a titanium suppressor would not add more - on not much more, maybe less - weight to a ~10" barrel than the difference in weight between the 10" and the 16" with flash hider).
The suppressor will weight more than the thin shroud and pencil barrel, fyi. I'm guessing 3-4 ounces more roughly
 

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I do not know if this is correct (someone please check) but I read somewhere the over all length of P90 / PS90 is a SBR issue. The long barrel with flash is designed to make both barrel and total weapon length non-SBR. If this is true, you might be able get by with a 16" barrel & suppressor by adding butt plate spacers. Apology if this is not correct.
P90/PS90
 
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