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Discussion Starter · #1 ·
Last October I bought a Sig Sauer MODX9 9mm suppressor from a local shop that had a kiosk to do form and fingerprints submittal. My $200 fee was promptly taken by the ATF and then the wait began. The shop said approvals were taking 12-15 months, I thought no way. Yes way. Even with the improvements for electronic filing nothing has changed. About four or five years ago I filed three Form 4s to make three suppressors an that only took about three months to get the stamp.

The MODX9 is 3D printed titanium, Sig is using this process for all of their suppressors now. Looking at it you could never tell it wasn't machined.

I shot a few rounds through it yesterday, hearing protection not required but the report was fairly loud. I've got subsonic ammo coming so that will dramatically improve the report.

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Nice

There is no reason for the delay, other than them purposely doing it.

I have been considering getting a .300 upper with suppressor for my AR Pistol, but just not sure I want to deal with the hassle, money or wait time.
 

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Very nice John. I want to join you in that club someday. Right now money is tied up building a shop. :D
 

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Discussion Starter · #4 ·
Bought a threaded barrel for my EDC (every day carry) Sig Sauer P365XL. About 1/2" of the barrel end (stainless steel) is exposed when the gun is holstered. Already had questions - "what's that sticking out of the holster..?"

Threaded barrels are expensive, at least for my Sig. All of the simple black finish barrels were sold out so I had to go high dollar ($170.) The feed ramp is polished so maybe this will work 100% with no FTF, FTE, etc.

However my P365XL is extremely reliable only having trouble with reloads. No problems with factory ammo.
 

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Lucky you still waiting on one, been 14 months now.

BTW the efile which was supposed to be faster and less than 90 days is running 7-8 months now
 

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Discussion Starter · #7 · (Edited)
Do you have the government's stamp before purchasing a silencer, and bringing it home?
You buy the suppressor (or other NFA item like a short barrel rifle), fill out the form, pictures, fingerprints, sign-off by local law enforcement, pay $200 and wait. And wait. Where I bought mine, they had a kiosk that recorded fingerprints, took a picture, and you could fill out the form.

Then when the paperwork (with a stamp) is returned to the dealer and you fill out the form 44xx?? 4473 just like you were buying a firearm.

Stupid hoops to jump through for a suppressor :mad:.
 

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You buy the suppressor (or other NFA item like a short barrel rifle), fill out the form, pictures, fingerprints, sign-off by local law enforcement, pay $200 and wait. And wait. Where I bought mine, they had a kiosk that recorded fingerprints, took a picture, and you could fill out the form.

Then when the paperwork (with a stamp) is returned to the dealer and you fill out the form 44xx?? just like you were buying a firearm.

Stupid hoops to jump through for a suppressor :mad:.
So, you can't take it home till the entire process is complete?
 

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And you hope the dealer is still around in a year or you start over... From personal experience...
 

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Discussion Starter · #11 ·
Exactly Mike! The place I bought the can from is KNS Precision in Fredericksburg, TX. The have an ancillary business of machining. What exactly they machine I have no clue but there's a lot of high end equipment in their building.

So my subsonic ammo came in and I fired five rounds through my AR pistol. With no hearing protection the sound was much quieter but not as much as I expected. Maybe it was because the muzzle end was relatively close to my head. Now I need to try the can on my carry gun.

Generally speaking, subsonic ammo is fairly expensive. 9 mm subsonic is expensive and somewhat difficult to find. I paid about 80 cents a round for this 9mm JHP (jacked hollow point - the only choice.) You can find 9mm target ammo for about 30 cents a round so it's really coming down in price.

One of my buddies is a reloader so I'm going to ask him if he can reload a bunch of subsonic 9mm for me - maybe requires a heavy bullet and light powder load. Don't know.
 

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John, most 147 grain 9mm is subsonic.
There are 3 factors for the noise
1) the gas leaving the barrel at supersonic speeds making a sonic boom. The suppressor will help mitigate this by slowing the speed of the gas.
2) the bullet leaving the barrel at supersonic speed, and subsonic ammo takes care of this
3) unburnt or still burning powder entering the can, and the gas leaving the can at high speed.

An AR pistol is a problem, the longer barrel may increase speed enough that subsonic ammo becomes supersonic. People believe there is a line that at this speed you go from subsonic to supersonic, but there is a whole area from 800 fpb to 1250 fps where you are trans-sonic, where you have both properties. Most subsonic ammo is really trans sonic and noisier than true subsonic ammo. I have loaded 357 mag ammo from 700 fps to 1300 fps, and even at 1000 fps, which is "subsonic" it is a lot louder than 800 fps.

The second issue of AR pistols is the burn rate of powder. Most powder for rifles burns slower, and in a barrel under 16" you get still burning powder in the suppressor. but with 9mm it is not the case, 5.56 is a whole other story though.

What length barrel are you running and what ammo did you use?

147 gr 9mm out of a 4-5" barrel will be 950-1000 fps, out of a 10" or longer barrel it will be close to 1100 fps, which is borderline subsonic.

KNS is well known in the gun industry, they make a lot of high end replacement pins and other gun parts. I run some of their products.
 

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Discussion Starter · #13 ·
Thanks for that in-depth report Mike. Very informative. Didn't know that about KNS. I was salivating at some of the long guns they have for sale in their small showroom.

My AR pistol has a barrel length of 8". Forgot what kind of 9 mm target ammo I was running in it, I have a Hinze 57 mix of ball ammo. The subsonic ammo I used was Corbon performance match, 147 grain JHP - the box was labeled subsonic. I buy most of my ammo from one place - they have 147 grain 9 mm they are advertising as subsonic but users report they aren't that quiet. Box packaging does not mention subsonic.

Just a day ago I watched a YouTube video by the Mark and Sam After Work channel about subsonic vs supersonic as far as accuracy. They are long range shooters in Australia (bolt long guns are legal there) and I would rate them as one of the top distance shooters in the world. Anyway he went into a brief but very interesting explanation about trans-sonic vs supersonic. Bottom line is there are many factors that come into play as you have pointed out.

I tried the can on my P365XL (3.7" barrel length) with the Corbon match ammo and the report was well muted vs no can. I shot 4 rounds of the Corbon and then in the magazine was Hornady Critical Defense loads. Surprisingly the Hornady ammo wasn't significantly louder than the Corbon.

One of the suppressors I machined (with an AFT stamp - all legal) is in .30 caliber. The can is about 11" long and I think I have 8 or 9 cone type baffles in it. 220 grain Blackout ammo is extremely quiet in that AR - it's a loud CLICK. I think the reason why my Sig can isn't quieter is due to the length and the passage hole diameter is relatively large (but I haven't measured it. Also the baffles are the simple cones (clipped.)
 
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