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Greg, I'm sure you know the answer to that question.Quote:
Originally Posted by Kiwi Greg
Usual quoted 'standard' is below 140db when tested with proper equipment, but even this can be 'unsafe' or painfull for some individuals in practice in certain circumstances.
Basically the quieter you can get them the better. Not necessarily how light you can get them. Results will also be very dependant on calibre and barrel length.
Actually I don't know the DB reading for hearing safe, is it 100-110-120-130 ?Quote:
Originally Posted by dfmaisey
I'm sure someone does ?
I appreciate it has something to do with volume over time as well.
I do know that one DB is a big difference, the bigger the number the bigger the difference being a logarithmic scale.
I know it makes a difference where, how & with what it is measured with & the atmospheric conditions at the time of testing.
I know that I have many suppressed rifles, ranging from .17 to 50 cal with many different suppressor brands.
I wouldn't shoot most of them at the range or in the field without hearing protection for more than the odd round or two.
I always wear good plugs & muffs when shooting at the range or targets.
I wear earmuffs everyday at work (joinery) & have done for, over 30 years now, get tested every year.
Having already damaged my hearing, mainly due to a severe flu that hospitalised me about twenty years ago, I want to hang on to what I've got left for as long as possible, my Father & brother in law are quite deaf (industrial) which can be extremely frustrating for everyone concerned.
Dammit Greg, I'm an engineer, not a medical doctor! :D Sorry, I just watched star trek over the weekend and couldn't resist.Quote:
Originally Posted by Kiwi Greg
Read this report: http://www.cdc.gov/niosh/docs/98-126/pdfs/98-126.pdf It provides a comprehensive overview on noise. I would especially like to draw your attention to table 1-2. Most hearing guides do not give any real data on noises at levels that even suppressed firearms produce.
Anything over 140 is considered to induce permanent hearing loss no matter what the duration. Most suppressor manufacturers use this and say "hearing safe" is under 140. That is somewhat misleading. Table 1-2 provides a guide for 8 hour cumulative noise at a given level that can be converted from time to number of shots. I used .002 for a shot duration to arrive at number of shots that are "safe" in a 8 hour day. This ranges from 48 shots at 139 to 360 shots at 131 dBA. IF you want to be more conservative, use .002 for subsonic rounds and .02 for supersonic since supersonic has a longer duration at a higher level due to the crack of the bullet. Subs drop off straight away due to no crack.
For best practice, plugs and muffs if you are shooting unsuppressed and if you are shooting supersonic suppressed, plugs and a can that is under 140. I shoot a lot of subsonic without any muffs and don't experience any discomfort. I will put up a vid later today of the pistol can shooting around 128 - 130 dBA. At that level, amplified muffs will amplify the shot sound rather than clipping it. It is louder through amplified muffs than it is without anything.
Getting a short barrel 308 AR10 down under 140 at the ear is a mission. On a bolt gun, it is easy. In fact, a bolt 308 can get down under 130 at the ear and is quite pleasant to shoot without plugs.
Here is the pistol can with subs to get an idea of under 130 sound levels.
UTU 9mm Titanium Suppressor on IPSC Shoot - YouTube
very impressive specs.Quote:
Originally Posted by ODL
This ODL 556-45 Samson suppressor Looks like it would be great on my 22Khornet.
Are you still going to produce a QD can that utilizes an A2 FH?
That would rock if the point of impact stayed about the same!Quote:
Originally Posted by Beavis
Hi ODL ,
Give me a week or so , have copied about 1/2 the articles , once done will post to you .
Later Chris
Yes, it will be right after the current QD is finished. I am doing a redesign on the brake to make it a machined part and to make it primarily a very good brake.Quote:
Originally Posted by Beavis
Keep in mind that an A2 FH can vary a lot from various manufacturer. I won't guarantee that it will work with every FH but it should work with all mil spec FH's. It also won't seal as well as the new QD design above. It will be very handy for those that want to use an A2 though and due to the weight, shouldn't change POI very much.
Thanks for that! Take your time. Keep in mind that all the big names have been chasing each other and doing much the same thing.Quote:
Originally Posted by ChrisF
With a few people in the states starting to take measurements from the ear instead of just the muzzle, I think there will be some redesigns on many products. The main one will be cans primarily optimized to bolt guns and cans optimized to SA. This is mainly to do with back pressure problems on SA that cause the sound signature at the ear to be more than at the muzzle on many cans.
Sound is sound and a can is only as good as the maximum sound level it produces on the rifle system whether it is at the muzzle or out the chamber. Frankly, pushing sound out the chamber to get a good muzzle number is bad for the rifle and bad for the shooter in my opinion. This is why I will produce data on all my new cans with sound at the right ear as well as mil spec at the muzzle.
Of course, you can change your gas system, change your buffer and a lot of other things but I will keep one rifle set up as a bog standard M4 so that I can get a feel for how the can is working. This is also why I give actual numbers rather than an ambiguous XX dB's. By giving all the test data on the rifle, ammo, where the measurements were taken, a customer can get an idea of how the product performs. Due to overly competitive marketing people at some companies, you get an XX dB rating that doesn't say if it was at the ear or muzzle and often you find that a can that is marketed as a "full auto rated can" is tested on a bolt gun for sound reduction.
I'd be happy with a FH option for your new QD design instead of an A2 attach can. Either one. Just don't want a brake.... FH is much nicer to be around..
Mean I want to out fit all my guns with an A2 FH so that would be the titsQuote:
Originally Posted by ODL
@ODL what is the retail on the 556-45 suppressors?
Currently 675 inclusive. This is likely to go up before the next batch though. I have one standing by if you want it. Just ring or email.
Here is an update on the new AR10 can.
Weight 225 grams
OAL 215
Length past muzzle - 158
OD 38
Length from shoulder to aft surface - 38
5/8-24 thread
Diameter of over barrel section -19.35
One blast baffle
One end baffle
Seven intermediate baffles
Exit aperture - 10mm
They should be ready for testing next week along with a new batch of the 556-45 Samson.
I just noticed , that you have made a Stainless Steel suppressor as well ?
Hi ODL ,
First off , well done on the Glock 17 suppressor , of all the browning tilting barrel pistols , the plastic framed pistols like the Glock etc are the more difficult to get working .
The alloy framed pistols like the Sig 226 are easier to get working compared to the Glocks .
Good to see you are also working with SS , as this hopefully will give you a model thats less in cost than a TI model , which may mean your cans get more wide spread use in NZ .
I have just sent out the photocopied articles , you should get it in a few days .
RE : Baffle design , one thing I have constantly heard from US makers , is that for rifles ( supersonic ) , the blast baffle ( 1st baffle ) should be symetrical , after that you can do pretty much anything , ie asymetrical .
With subsonic , ie most pistol cals , you can use either symetrical or asymetric , as the 1st baffles etc .
If you look at the mono core Titan , which was designed for the 338LM , you will see , blast baffle is symetrical , then all the rest are asymetircal ( slanted to bore axis ) , the Titan is a mono core thats the slipped into a tube thats has holes drilled in a pattern to match the interoir design , then plug welded .
The " K " baffles where made originally for pistol cals , and work well for them , be aware that they can be a little weak for rifle use , as they can colapse unless strenghtened ,
Omega baffles can be use on either pistol or rifle , they suit a wider can , as the spacer is under sized , and this makes a co ax effect .
Sent the pattern drawings for Omega , and K baffles , the notched stepped cone baffles that a few makers use , are a modification on the Omega .
Also sent pics of the Ase Utra , Jet Z baffles ( blue ) , and the S baffles of their SS design .
Most current designs , use normal CNC/lathes & simple casting or stamping in the manufacture , as you are using 3D printing your designs donot need to be consticted by normal manufactoring methods .
In pistols , in 9mm , Glock & Sig 226 dominate , so cans that function on these 2 will cover most users , I would think you may need different Neilsen devices , one for the Glock & one for the Sig .
Yours Chris
I am waiting on your 308 suppressor that mounts over a brake , as I think it will suit a PH rifle I have .
So I am interested in 3 TI models , the 308 & 338 boltgun cans over brake ones , and maybe a 9mm can as well , the 308 would be a 5/8x24 & the 338 std AI , 18x1.5mm ,
Later Chris
Hi - do you have a price on this yet?
Cheers
Quote:
Originally Posted by ODL
We will have some ODL cans at the Sika Show.
Thanks for that Chris! Yes, all my first blast baffles are symmetric with a "brake" of sorts to release the initial blast off the bullet as clean as possible. I have some really trick baffle technology for the middle ones and the last one is symmetrical of course.
The SS can is 15-5 for full auto use and is actually dearer than the ti can. I am exploring low cost options for bolt cans for future development once the sound is optimized on the ti models. Thanks for the kind words on the Glock can. It is really fun to shoot. They are fussy and I may have to change springs since the Gen 4 Glock spring is different to the older ones and may need to be rewound.
Price on the AR10 can will be in the 800 range. It still needs optimization but it is getting close. Digit will have an example this week.
Yes ,
I thought the Gen4 may need a different booster , its sad that Glock does not really make threaded barrels for suppressors like Sig does , the American Glock factory has just made a few factory suppressor barrels , but they are for the gen3 model & not the newer Gen4 Glock .
Maybe get a Glock 17 gen4 , and buy a extra Glock 34 gen4 barrel & thread that to the USA Glock/Sig spec , fro 9mm , which I think is 13.5mm LH .
Lone Wolf, Storm Lake and AAC make threaded Glock barrels.
YES , But I wanted a Factory barrel , not a after market one , Sig do them , and Glock should , but dosnt .
Thanks for the package of info Chris. I just finished it and it is good to relook at things from a fresh perspective. I especially liked reading Olsen since he is such a legend in the field and some of his concept descriptions are pretty good.
Glock is selling factory barrels and I am trying to get some. They are 13.5x1 LH and have a unique profile before and after the thread. I have a new spring rate I will be trying next week in the Gen4.
Any news on the bolt action QD brake cans ? , also have you thought of putting the 9mm carbine can on the glock to see if it gives better dB reduction ?
Yours Chris
ODL,Quote:
Originally Posted by ChrisF
I share Chris' enthusiasm for 308 & 338 bolt action specific, over barrel or can type, both 18x1.5mm
How much to make me a TI action ? , using bolt & locking ring off a Badger M2008 action
Quote:
Originally Posted by ODL
Hi ODL, How's the 308 suppressor testing going on? and a time line for production?.
Sorry for the delay in responding.
Summary of the sound test on a 16" DPMS 308 was 141.3 at the muzzle and 143.4 at the ear with R1M1 SA ammo shooting 2484 FPS. Without a can (bare barrel) the muzzle sound was 167.2. The same can on a 20" bolt gun was 141.5 Muz and 128.5 Ear. So close to target, but not there yet. The at ear level could be brought down with adjustment of the gas block. It was not changed or adjusted for this test.
I am printing a new test can with several mods. If I can get a short 308 to 140 or less at the ear and muzzle with this size can I am calling it good. Then I will print a batch of both the AR10 and AR15 cans for stock.
Sorry Chris, I will not be doing any custom design work for a year as I have too many other designs to finish. Namely the QD and a new 338 thread on for an overseas customer. I have to say that reviewing your info did make me think of new ways of looking at design and while my changes are far different than what was done in the past, rethinking about design concepts helped me (will know how much at the end of the week) with some things that have not been done yet, so thanks again for the copies.
Saw one of these over the weekend.
Over barrel, thread on inside - 3d printed titanium - very cool :thumbsup: