Thread: Oceania Defence suppressors

ODL I am still after a can for my 6.5 bolt gun, if only u would make 6.5 or even a 30 cal can threaded 1/2 x 28TPI I would be in for one.

Is this likely to happen ? I know you have concerns regarding "thread strength" but most other can makers will do a can in this calibre with this thread. Is it a particularity with materials you are using that makes this an issue??

It isn't that the threads are too weak so much that for a 308 can they are non standard. I will have to make a custom can and if I do that I might as well make the bore tighter and add your name to it since it will be a one off design.

If you want to get a custom can, let me know how much powder you are using and I will research the muzzle pressure and start the process. It will be dearer than a standard can, but you can customize it for length and even external design if it isn't too involved.

As Chris said, I can make it longer and quieter or shorter and not as quiet. The larger the bore size gets, the less negotiable the length gets to keep it reasonably quiet. The 556-45 Samson is really at the minimums as to what can be done. I basically added 25mm to the length of the original can but reduced the volume to 67% of the original.

Man that is outstanding performance from such a small can.

Originally Posted by ODL

It isn't that the threads are too weak so much that for a 308 can they are non standard. I will have to make a custom can and if I do that I might as well make the bore tighter and add your name to it since it will be a one off design.

If you want to get a custom can, let me know how much powder you are using and I will research the muzzle pressure and start the process. It will be dearer than a standard can, but you can customize it for length and even external design if it isn't too involved.

As Chris said, I can make it longer and quieter or shorter and not as quiet. The larger the bore size gets, the less negotiable the length gets to keep it reasonably quiet. The 556-45 Samson is really at the minimums as to what can be done. I basically added 25mm to the length of the original can but reduced the volume to 67% of the original.

OK point taken

Please define "hearing safe"

Originally Posted by Kiwi Greg

Please define "hearing safe"

Greg, I'm sure you know the answer to that question.

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.

Originally Posted by dfmaisey

Greg, I'm sure you know the answer to that question.

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 ?

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.

Originally Posted by Kiwi Greg

Please define "hearing safe"

Dammit Greg, I'm an engineer, not a medical doctor! Sorry, I just watched star trek over the weekend and couldn't resist.

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

Originally Posted by ODL

ODL 556-45 Samson specs:

OAL - 170.5
Weight - 167 grams
OD - 38
Aft of can to barrel shoulder - 43
End of muzzle to end of can - 110.5
ID of over barrel section - 19.15
Thread - 1/2-28 tpi
One blast baffle
One end cap baffle
Six intermediate baffles using two designs for primary and secondary.
Bullet aperture is taper cut with an exit hole of 7.6mm.

They will be in heat treat over the weekend and will be coated on Tuesday.

very impressive specs.

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?

Originally Posted by Beavis

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!

Hi ODL ,

Give me a week or so , have copied about 1/2 the articles , once done will post to you .

Later Chris

Originally Posted by Beavis

Are you still going to produce a QD can that utilizes an A2 FH?

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.

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.

Originally Posted by ChrisF

Give me a week or so , have copied about 1/2 the articles , once done will post to you .

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.

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.