Hello All,
I’ve been a long time lurker. Reading, studying, taking notes and learning a lot from all of you. Thank you for this sight!
Will you please critique my 308 design?
The host is a Remington 700 .308 AAC-SD with a 20” threaded 1/10 barrel.
My goals for this build in order of importance: 1. Accuracy/minimal shift in POI 2. sound suppression 3. Light weight
Materials: Tube: Ti grade 9. All other components 316 stainless steel. Debating on if the extra cost justifies making the entire suppressor out of Ti. I think it would be around $400 more.
Thank you,
Gun Mechanic
308/7.62 Design review
Re: 308/7.62 Design review
You will have a pretty good performer there.
I suggest you round off the sharp corners on the bottom of the cones. Also, I would clip them.
Welcome.
I suggest you round off the sharp corners on the bottom of the cones. Also, I would clip them.
Welcome.
Kyle O.
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Re: 308/7.62 Design review
Thanks Kyle! As you can probably tell, some of my inspiration came from your posts/build. How did your 308 build turn out? I never could find your post on the end product.
What do you mean by clip?
What do you mean by clip?
Re: 308/7.62 Design review
Little half moon shapes cut out of the entry holes of the baffles. It causes cross jets of gas to push things off center of the bore line, and hold the stuff inside the can just a wee bit longer.pdx Gun Mechanic wrote:Thanks Kyle! As you can probably tell, some of my inspiration came from your posts/build. How did your 308 build turn out? I never could find your post on the end product.
What do you mean by clip?
It makes enough difference on centerfire rifle that I could tell a difference (just barely) with my ears, which tells me it likely reduces report by 5-6 decibels. The SDN6, Spcewar, and the Saker all have this feature, so I took their word for it.
Like this.
Kyle O.
Re: 308/7.62 Design review
Around $200/ft more for Gr5 Ti vs 316 1.5" bar stock if you're looking at online metals so your estimate of $400 is probably pretty close. Titanium Joe has better prices for that material. But you could just do the cones w/o attached spacers out of Ti and use tube for spacers. That would use a lot less bar stock & keep the Ti cost lower if you wish.
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- whiterussian1974
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Re: 308/7.62 Design review
DrK, which part of the Cone Mouth would you round? Wouldn't gas erosion smooth any sharp edges around mouth and carbon coat edges around base?Dr.K wrote:I suggest you round off the sharp corners on the bottom of the cones. Also, I would clip them.
Or did you mean cone base needs attention?
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The Death of One is a Tragedy, a million only a statistic.-Stalin
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Re: 308/7.62 Design review
are you planning on welding this together?
Re: 308/7.62 Design review
With my first few cans I left a sharp edge at the bore line. Accuracy was fantastic then after several hundred rounds I seemed to be getting contact and accuracy degraded terribly. Upon inspection I noticed little spikey fingers growing inward toward the center axis. They were contacting the bullet slightly.whiterussian1974 wrote:DrK, which part of the Cone Mouth would you round? Wouldn't gas erosion smooth any sharp edges around mouth and carbon coat edges around base?Dr.K wrote:I suggest you round off the sharp corners on the bottom of the cones. Also, I would clip them.
Or did you mean cone base needs attention?
Material was 316L stainless, and after putting a nice smooth polished rouned edge on each baffle, accuracy was restored, and I have had no issues since, and have fired several hundred rounds.
Now when I see sharp angles on 316 I warn of this phenomenon.
Kyle O.
- whiterussian1974
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Re: 308/7.62 Design review
Maybe it's caused by one of the constituent materials in the alloy? https://en.wikipedia.org/wiki/Whisker_( ... #MechanismDr.K wrote:Upon inspection I noticed little spikey fingers growing inward toward the center axis. They were contacting the bullet slightly.
Material was 316L stainless, and after putting a nice smooth polished rouned edge on each baffle, accuracy was restored, and I have had no issues since, and have fired several hundred rounds.
I was aware of Whiskering in electronics. Perhaps in other environments and apps too?
The Darkest Corners of Hell are reserved for those who remain Neutral!-Dante
The Death of One is a Tragedy, a million only a statistic.-Stalin
silencertalk.com/forum/viewtopic.php?f=10&t=135314
The Death of One is a Tragedy, a million only a statistic.-Stalin
silencertalk.com/forum/viewtopic.php?f=10&t=135314
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Re: 308/7.62 Design review
Fascinating! I never heard of whiskering. From the article:
Some of that could happen inside a suppressor, I suspect!The mechanism behind metal whisker growth is not well understood, but seems to be encouraged by compressive mechanical stresses including:
[*]residual stresses caused by electroplating,
[*]mechanically-induced stresses,
[*]stresses induced by diffusion of different metals, and
[*]thermally-induced stresses.
- whiterussian1974
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Re: 308/7.62 Design review
The last 3 definitely. It's good to know that DrK has had great results w rounding the sharp edges. That and adding lead or Nickel-plating are 2 of the Mitigation Strategies suggested.DanielWilson wrote:Fascinating! I never heard of whiskering. From the article:Some of that could happen inside a suppressor, I suspect!The mechanism behind metal whisker growth is not well understood, but seems to be encouraged by compressive mechanical stresses including:
[*]residual stresses caused by electroplating,
[*]mechanically-induced stresses,
[*]stresses induced by diffusion of different metals, and
[*]thermally-induced stresses.
I prefer DrK's solution.
The Darkest Corners of Hell are reserved for those who remain Neutral!-Dante
The Death of One is a Tragedy, a million only a statistic.-Stalin
silencertalk.com/forum/viewtopic.php?f=10&t=135314
The Death of One is a Tragedy, a million only a statistic.-Stalin
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Re: 308/7.62 Design review
I see now! Does it affect accuracy? I'm trying to go for optimal accuracy.Dr.K wrote:Little half moon shapes cut out of the entry holes of the baffles. It causes cross jets of gas to push things off center of the bore line, and hold the stuff inside the can just a wee bit longer.pdx Gun Mechanic wrote:Thanks Kyle! As you can probably tell, some of my inspiration came from your posts/build. How did your 308 build turn out? I never could find your post on the end product.
What do you mean by clip?
It makes enough difference on centerfire rifle that I could tell a difference (just barely) with my ears, which tells me it likely reduces report by 5-6 decibels. The SDN6, Spcewar, and the Saker all have this feature, so I took their word for it.
Like this.
If it doesn't affect accuracy, do you know how to draw it up in Solidworks and know the best method to machine it?
I"m on the fence. I'd like to have the ability to take it apart for cleaning.57fairlane wrote:are you planning on welding this together?
Re: 308/7.62 Design review
I was concerned with accuracy issues as well, but alas it is just as accurate as before.pdx Gun Mechanic wrote:I see now! Does it affect accuracy? I'm trying to go for optimal accuracy.Dr.K wrote:Little half moon shapes cut out of the entry holes of the baffles. It causes cross jets of gas to push things off center of the bore line, and hold the stuff inside the can just a wee bit longer.pdx Gun Mechanic wrote:Thanks Kyle! As you can probably tell, some of my inspiration came from your posts/build. How did your 308 build turn out? I never could find your post on the end product.
What do you mean by clip?
It makes enough difference on centerfire rifle that I could tell a difference (just barely) with my ears, which tells me it likely reduces report by 5-6 decibels. The SDN6, Spcewar, and the Saker all have this feature, so I took their word for it.
Like this.
If it doesn't affect accuracy, do you know how to draw it up in Solidworks and know the best method to machine it?
I"m on the fence. I'd like to have the ability to take it apart for cleaning.57fairlane wrote:are you planning on welding this together?
I would also suggest threading the endcaps. Factory cans are welded I suspect mainly for liability issues (I do know the increased strength issue as well), but since your making it yourself, go ahead and go all the way. I've had no issues with threads, I put a drop of red locktite in my threads, and pretend they are welded, but in the event of needing to get in there, a little heat and viola. Not so easy if welded.
Perfect example was when the whiskers popped up, had the can been welded, I'd have had to take an entirely different approach to fix it. Also, I was able to do a comparison of clipped vs. not clipped.
And say sometime down the road one of us comes up with a fantastic new....whatever....lets pretend.....say drill a 3/32 hole halfway up the 3rd baffle for a 50 decibel decrease in report....We would certainly want to get into that silencer to do that!
I see more advantage to threading the endcaps. If you are taking the thing to war, and need to beat someone to death with it.....well, weld that puppy up tight.
Kyle O.
Re: 308/7.62 Design review
Clipped happened to be better for you but I'm not sure that welding the caps has a downside with respect to the clip or not to clip issue. Technically, if the clipped cones don't work as well as the un-clipped ones, you're still stuck with them with a Form 1. Even if you are able to open-up the can, you won't know what works best until after you clip them and then you're stuck with them.Dr.K wrote: Also, I was able to do a comparison of clipped vs. not clipped.
Last edited by calinb on Fri Aug 01, 2014 1:11 pm, edited 1 time in total.
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Re: 308/7.62 Design review
Ok, back to business. Been away but I'm back on track.
Dr. K,
what do you think of the radius I put on the OD of the cone tip? Is this what you are talking about? How does it look to you? If it looks good, I'll work on the clipping next.
Dr. K,
what do you think of the radius I put on the OD of the cone tip? Is this what you are talking about? How does it look to you? If it looks good, I'll work on the clipping next.
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Re: 308/7.62 Design review
like this?