Yes, it can be legal to make a silencer. For everything Form-1, from silencer designs that are easily made, to filing forms with the BATF, to 3D modeling. Remember, you must have an approved BATF Form-1 to make a silencer. All NFA laws apply.
I just finished my first form 1 can and am not impressed so far. Test rifle is 10.5" AR shooting 300 blk. I went to an outdoor range yesterday and was a little surprised by how loud it was. I have shot plenty of others suppressors, form 1 and commercial. I thought that my factory rounds were possibly going supersonic (Hornady BLACK 208gr. Amax and Remington whitebox 220gr).
Thought maybe my expectations were just a little high so I went to a buddies today who has an indoor range and shot some known subsonic hand loads. Put it up against two other 30 Cal. cans (Gemtech and Stealth) and while a little louder than the stealth it was noticeably louder that the Gemtech.
Here are the specs.
-DM Ti 7.6" tube and end caps
-Z Machineworkz 60 deg cones (7) bore diam at .380 to .390
-1.5 " blast chamber
Stack is as follows:
Direct thread end cap, 1.5" Ti spacer, Cone (.390" bore), .20 spacer, Cone (.390" bore), Cone (.385" bore), Cone (.385" bore), Cone (.385" bore), Cone (.383" bore), Cone (.380" bore), Dm coned endcap (.400" bore)
Any suggestions from the veterans here on how i can quiet this down some more? Any help is greatly appreciated.
Indeed, plain cones aren't doing anything to redirect flow across the bore. Running a flat cutter across 1/2 of the nose of each of the cones except the first and last and arranging them in alternating order should drop the noise considerably. Cutting down about 1/8" should be a help. Trying that then testing will tell you if going a bit deeper is needed.
a_canadian wrote:This is a solid example from CurtisTactical:
When HPA passes considering exploring a design sketched long ago:
the clipped cone as above with the added feature of introducing 2
opposite creases running from apex to base. Inspiration came from
noticing my Vitamix juice blender's walls* - cross section a square with dimpled
middles.
At high speed the surface of the heavy blend is a surface like the ripples
in an undulating wings of a manta ray.
We see the effectiveness of such a 'clipped' Rieman surface in the
new Ruger Silencer.
Notional way to dimple would be to machine an insert to the cone
and then press in as for instance in prehistoric times when Manual Glass Juicers
were in use the ribbed surface.**
BS flag waving. STOP. Don't clip your cones expecting magic. Clipping will not transform marginal into outstanding. In this application at best it will make very good a wee little bit better - and you might need a meter to tell if it did.
What is your baffle spacing? You listed one measurement of .200 but that looks like just a little piece to take up slack. How long are those skirts? You want to be in the .600-.700 neighborhood for spacing. Something else is wrong though. That should be making 300BLK subs hollywood. You have excessive gap between the cones & tube ID or some other fundamental flaw in the construction. Your bore is on the larger side for .30cal. How are you getting your measurements - and are they accurate? Is it possible that is your calculated drill size but it actually measures oversize? Were you measuring those holes with the back side of calipers (wrong way to measure a hole accurately) - wondering how you got those bore diameters since no common fractional or letter drills are those diameters. 9.x mm drills by tenths?
Anyway, I'm thinking you have something going on that is letting the gas bypass the baffles and simply not get worked enough. First things that come to mind are excessive clearance inside tube or oversized bore diameter. What are the specs and actual measurements of the tube and baffles? List those and how you are getting those numbers. But 8 plain old unclipped 60° cones will make 300BLK Hollywood if everything else is right.
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These things make me
I see what your saying CMV, with regard to bore and baffle to tube clearance, but I see it playing no part. Shooting 300blk thru my Octane 45 is quiet and added clearance would just serve as a coaxial chamber; effectively trapping more gas.
I agree w/ you in that there's no way this build is not quiet. 7 cones in an 8" suppressor with SS ammo? Your expectations might be a bit high. Also, that clipping the baffles won't exhibit a night & day difference, but should be done anyway.
My only thought, and only because I've never seen or used that type of design, is that the endcap is creating an unpleasant tone. Not necessarily making the suppressor inefficient, just not complementing the overall package. While Mfr's report dB numbers measuring the sound pressure level, they don't report the frequency curves. A 130dB gunshot , registering in the higher frequency band, will sound harsher (to the ear) than one at 133dB, but output at a much lower frequency; even though it is twice as loud.
Don't forget, you're using it on an AR and now the bolt stroking is a factor that wasn't accounted for, before the suppressor. And you note using a Stealth silencer. Which one? They make about 2 dozen different 30cal silencers in all sizes, lengths, and baffle configs. Gemtech currently has about a dozen 30cal silencers, too.
Calipers are plenty accurate enough to measure an ID. They have to have an edge, not flats though. Maybe it's not accurate to half thou, but for measurements like this it's fine.
My .375" bore 300blk baffles are very quiet, and like trex said, 9mm 40 and 45 cans suppress 300 blk pretty well so don't chalk this up to oversized bore. .390 is big but it should still work.
The cones should be clipped regardless. I never claimed they were gonna make his silencer sound fantastic, I said it'd make it sound better.
300 blackout form 1: http://www.silencertalk.com/forum/viewtopic.php?f=10&t=137293
5.56 form 1:
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=141800&p=955647#p955647
The only reason I'd not clip those cones would be if intended use was on a precision benchrest gun. Which isn't the case here. And last fall a benchrest guy showed his conical baffle can here with symmetrical clipping to avoid cross-bore jetting causing groups to open up. He said his rifle remained just as accurate, with only a slight POI shift when putting the can in place, and that probably owing to changed harmonics. He left the first and last baffle intact, not clipped.
CMV,
Thanks for the response. Interesting input about clipping. There seems to be a split on exactly how much difference it will make.
In any case you are correct the .200" spacer is just to take up slack. Skirts are .67". Gap between cones and tube is very minimal. Cone skirt OD is 1.372 (+/-.002) and tube ID is 1.375 so no issue there. Bore is a touch large but I don't think it accounts the sound, there are factory cans in this range and I wanted to stay on the safe side. Cone bore was cut on a lathe so no drilling was involved. Bore size was verified with calipers (two sets to be sure) and was taken correctly in several spots to verify.
I honestly am at a loss here. Specs for Z Machine worxs cones are 60 deg cones are are;
1.372 OD
.67 Skirt
1.42 OAL
.42 Face
.72 Cone
Tube is from Diversified Machine and is 1.5 OD, 1.375 ID, 8"L, Direct thread. All of these measurements are listed on the company pages and have been verified by me.
T-Rex wrote:I see what your saying CMV, with regard to bore and baffle to tube clearance, but I see it playing no part. Shooting 300blk thru my Octane 45 is quiet and added clearance would just serve as a coaxial chamber; effectively trapping more gas.
I agree w/ you in that there's no way this build is not quiet. 7 cones in an 8" suppressor with SS ammo? Your expectations might be a bit high. Also, that clipping the baffles won't exhibit a night & day difference, but should be done anyway.
My only thought, and only because I've never seen or used that type of design, is that the endcap is creating an unpleasant tone. Not necessarily making the suppressor inefficient, just not complementing the overall package. While Mfr's report dB numbers measuring the sound pressure level, they don't report the frequency curves. A 130dB gunshot , registering in the higher frequency band, will sound harsher (to the ear) than one at 133dB, but output at a much lower frequency; even though it is twice as loud.
Don't forget, you're using it on an AR and now the bolt stroking is a factor that wasn't accounted for, before the suppressor. And you note using a Stealth silencer. Which one? They make about 2 dozen different 30cal silencers in all sizes, lengths, and baffle configs. Gemtech currently has about a dozen 30cal silencers, too.
T Rex,
I agree there is no way it should not be quiet. It is QUIETER than no can of course, but not like comparable setups I've shot. Also I realized what with an AR action will come additional noise and am factoring that out of my opinion. It could be tone, but it sure sounds like db's to me.
Asking buddy now for models on the other suppressors, but both were direct threaded on my gun for comparison and were ~8", 30Cal suppressors,
fishman wrote:Calipers are plenty accurate enough to measure an ID. They have to have an edge, not flats though. Maybe it's not accurate to half thou, but for measurements like this it's fine.
My .375" bore 300blk baffles are very quiet, and like trex said, 9mm 40 and 45 cans suppress 300 blk pretty well so don't chalk this up to oversized bore. .390 is big but it should still work.
The cones should be clipped regardless. I never claimed they were gonna make his silencer sound fantastic, I said it'd make it sound better.
Agreed and will clip because at this point it won't hurt anything,
Is it possible to put the smallest bore cones toward the rifle and the larges toward the muzzle and of the suppressor?
Again, not going to be huge but you may get 1 or 2 dB this way if you can, and if clipping gets you another 2 or 3 then you're going to be able to notice that.
I just finished my first form 1 can and am not impressed so far. Test rifle is 10.5" AR shooting 300 blk. I went to an outdoor range yesterday and was a little surprised by how loud it was. I have shot plenty of others suppressors, form 1 and commercial. I thought that my factory rounds were possibly going supersonic (Hornady BLACK 208gr. Amax and Remington whitebox 220gr).
Thought maybe my expectations were just a little high so I went to a buddies today who has an indoor range and shot some known subsonic hand loads. Put it up against two other 30 Cal. cans (Gemtech and Stealth) and while a little louder than the stealth it was noticeably louder that the Gemtech.
Here are the specs.
-DM Ti 7.6" tube and end caps
-Z Machineworkz 60 deg cones (7) bore diam at .380 to .390
-1.5 " blast chamber
Stack is as follows:
Direct thread end cap, 1.5" Ti spacer, Cone (.390" bore), .20 spacer, Cone (.390" bore), Cone (.385" bore), Cone (.385" bore), Cone (.385" bore), Cone (.383" bore), Cone (.380" bore), Dm coned endcap (.400" bore)
Any suggestions from the veterans here on how i can quiet this down some more? Any help is greatly appreciated.
quiettime wrote:
Also may consider trying a few different ammo
Most factory sub sonic ammo will be disappointing in anything less than a 16" barreled AR. Even then it's questionable.
The UMC will suck, the Hornady not far behind.
A lot of people seem to think the Gemtech and Sig offerings are better. But if you want quiet in an SBR handloads, are what you really want to explore.
I just finished my first form 1 can and am not impressed so far. Test rifle is 10.5" AR shooting 300 blk. I went to an outdoor range yesterday and was a little surprised by how loud it was. I have shot plenty of others suppressors, form 1 and commercial. I thought that my factory rounds were possibly going supersonic (Hornady BLACK 208gr. Amax and Remington whitebox 220gr).
Thought maybe my expectations were just a little high so I went to a buddies today who has an indoor range and shot some known subsonic hand loads. Put it up against two other 30 Cal. cans (Gemtech and Stealth) and while a little louder than the stealth it was noticeably louder that the Gemtech.
Here are the specs.
-DM Ti 7.6" tube and end caps
-Z Machineworkz 60 deg cones (7) bore diam at .380 to .390
-1.5 " blast chamber
Stack is as follows:
Direct thread end cap, 1.5" Ti spacer, Cone (.390" bore), .20 spacer, Cone (.390" bore), Cone (.385" bore), Cone (.385" bore), Cone (.385" bore), Cone (.383" bore), Cone (.380" bore), Dm coned endcap (.400" bore)
Any suggestions from the veterans here on how i can quiet this down some more? Any help is greatly appreciated.
quiettime wrote:
Also may consider trying a few different ammo
Most factory sub sonic ammo will be disappointing in anything less than a 16" barreled AR. Even then it's questionable.
The UMC will suck, the Hornady not far behind.
A lot of people seem to think the Gemtech and Sig offerings are better. But if you want quiet in an SBR handloads, are what you really want to explore.
Sig 220 and American eagle 220 is quiet in my sbr. the fact that the can is longer than the barrel probably has a lot to do with that though. I've fired factory subs through someone else's can and rifle that weren't quiet at all. Not sure if it was the can or ammo though, it was a 16" with an osprey 45
300 blackout form 1: http://www.silencertalk.com/forum/viewtopic.php?f=10&t=137293
5.56 form 1:
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=141800&p=955647#p955647
fishman wrote:
Sig 220 and American eagle 220 is quiet in my sbr. the fact that the can is longer than the barrel probably has a lot to do with that though. I've fired factory subs through someone else's can and rifle that weren't quiet at all. Not sure if it was the can or ammo though, it was a 16" with an osprey 45
I have never tried, but it would not surprise me if a super actually sounded quieter than the UMC subs to the shooter.
Been a few years since shooting any Hornady and I don't remember if I tried a short barrel.
The powders used in most commercial ammo that can cycle a carbine gas system, without a suppressor, are really tough to suppress. They do keep people from complaining that the ammo won't cycle and that's about the only plus they offer.
Good to hear Federal might have something worked out.
