Thank you everyone for your design feedback. It is very appreciated!
mr fixit wrote:looking at your drawing, taking one spacer and one baffle together look like a single "Omega" baffle. That is what the patent is for, not stepped cones.
viewtopic.php?f=10&t=121887
Where did you get the idea/drawing?
The drawing is a model I made in Solidworks.
So far as the idea, the design process went as such:
Having read of lots of pleased folks with the Octane 45 on the .300blk with sub-sonics, I figured I'd start off with finding out the max possible internal volume of an Octane 45 (10.26ci). Needing to be at 1.25" OD max, I calculated the length of tube I'd need to get to a similar volume - 10.5" gets me 10.34ci. Both measurements assume .065" wall thickness.
After reading up on rifle can designs, it seemed cones/M baffles were preferred. Speaking of which -- I haven't been able to figure out from reading what the functional difference is between the two, if any. It seems like the main difference is which side of the "baffle" the "spacer" is attached to. Is that really the difference, or is there something more subtle that I'm missing?
Anyhow, not wanting to spend unnecessary hours at my manual lathes (as lathe use tends to increase my chiropractor bills...) I didn't want to make the baffles out of billet so I "broke them apart" into separate baffle "flats" and tubular "spacers" (this also lends itself to mixing a SS "flat"/baffle with an aluminum "spacer" for a bit of weight savings). Given the "dicta" of cone/M baffles, I figured that since cones/M's are smooth and turbulence is a good thing in cans, stepped cones/M's must be better. The steps also increase surface area which helps with heat transfer. At that point I wanted to try and maximize surface area and turbulence so I added a slight radius to each of the steps (it also cuts down on weight, although minimally). Thinking about it now, I may also want to add a radius on the outer diameters of each step... Flow separation here I come! (Deliberate attempts at flow separation are also why there is a step going from the 30* angle of the baffle back-side to the baffle spacer).
So far as the spacers, I initially did them as having an OD the same size as the ID of the outer tube, but while adding in the radii to the baffle steps I realized I could get more surface area for heat-sinking by reducing their diameter and exposing the outer tube to the combustion gases directly. Given the patent links posted, this seems to be where I stumbled into "Omega" territory.
It's a simplistic approach, to be sure, but with no prior personal experience to draw from it's what I've got to work with. I'm also not a fan of just directly (and intentionally...) copying someone elses' work (a-la opening up some of my personally owned cans and copying the guts) as that takes the fun out of the journey and I find that you don't learn nearly as much that way.
I'm also going to revise the end caps to be fully inset into the tube. That should reduce the weight another half an ounce or perhaps even a bit more.
As it sits, about 55% of the weight of the can is in the outer tube!
Given benders input, I'll look into the possibility of TI tubing as that would be a *MASSIVE* weight savings.
Bendersquint wrote:- You can probably remove a couple baffles and meet your goals.
Ok. We may have to give that a whirl too then (e.g. 2nd F1).
Bendersquint wrote:- For anything supersonic rated you should use either SS or Ti for the tubing, remember that part can't be replaced so make sure it lasts.
How is super-sonic so different from subsonic? Is it really just the few thousand PSI extra from the muzzle? Or does the sonic wave generated by the bullet become a factor as well?
Bendersquint wrote:- Ti is really not that hard to work with(especially with the equipment that you have).
As noted, we'll give it more thought. That will probably come down to a materials cost decision. I'd probably still go with SS for the caps, so instead of welding I'd thread the caps in. Are threaded caps an issue in a can/situation like this? I know TI can be welded to SS, but that's just further complication to an already new process - which, again, is not my preference for this particular project.
Bendersquint wrote:- "Blast spacers" thats the patent issue noted above.
By "blast spacers" I was referring to the two spacers surrounding the "disk" at the muzzle end of the can. As the disk is only 1" from the muzzle, I don't know if that's enough space to be effective. Would it be more useful at 1.5" from the muzzle?
Bendersquint wrote:- "Clipping" in any of the various definitions of the term can have accuracy issues if not done correctly, too deep, wrong angle, too large etc.... As far as sound reduction benefit, the Form1 builder will experience more of a notable change than most manufacturers doing it, so try the "clipping" a little at a time until you are happy.
The accuracy issue is exactly why I'd want to try and keep it symmetrical. I'd hope that the accuracy issues would arise from unequal movements of the gas surrounding/behind the bullet so making them symmetrically should limit those sorts of issues.
Bendersquint wrote:- Yes, supersonic 300BLK is considered a high pressure round.
For my own edification, at what pressure level does a particular cartridge become a "high pressure" round vs. a "low pressure" one? Also, what pressure measurement would one go by? E.g. Muzzle pressure or max chamber pressure?
My apologies if these sorts of things have been covered previously on here, but I haven't really stumbled across much discussing these aspects of suppressor design in my searches.
Thanks again to everyone!
