K baffle alignment

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fishman
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K baffle alignment

Post by fishman » Wed Apr 13, 2016 4:47 pm

my form 1 should be back any day now so its almost time to start making baffles.
I plan to include alignment tabs on my K baffles. what way is the best to align them? all aligned, 180* offset, or some other angle (90*, or 120* perhaps)

its for a subsonic 300 blackout if that matters.

i ran solidworks flow analysis on the stack with baffles 180* from each other and with them all aligned. them all aligned seemed much more turbulent but i know that a continuous flow analysis is not a good model for silencer performance.

am i wasting my time putting alignment tabs on at all? what do you guys think?

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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

quietoldfart
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Re: K baffle alignment

Post by quietoldfart » Wed Apr 13, 2016 6:42 pm

Why are you milling the waist vent from the face of the baffle? Seems to both weaken that edge unnecessarily, leading to premature erosion, as well as reduce efficiency of the port compared to the conventional milling from the cone side for this exit vent.

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fishman
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Re: K baffle alignment

Post by fishman » Wed Apr 13, 2016 7:06 pm

quietoldfart wrote:Why are you milling the waist vent from the face of the baffle? Seems to both weaken that edge unnecessarily, leading to premature erosion, as well as reduce efficiency of the port compared to the conventional milling from the cone side for this exit vent.
my thought process behind it was: milling away more material, by milling from the face instead of from the skirt, would better direct the gasses that are traveling through the bore away from the centerline of the bore, causing more gas to hit the face of the next baffle instead of just passing through the baffles along the bore
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

quietoldfart
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Re: K baffle alignment

Post by quietoldfart » Wed Apr 13, 2016 7:43 pm

Bearing in mind that my only experience with suppression has been airguns (between a few FPE and about 37fpe) and .22lr (pistol and rifle), it's my understanding that with subsonic rounds the best efficiency can be derived from a K baffle using the fore/aft milling approach for that pair of vents. And the recent expert consensus seems to hold that milling parallel to the bore, not in from an angle across the boreline, seems to offer better suppression. Getting material out of the way doesn't seem to be nearly so effective as 'working the gases' as they put it. A more positive approach is preferable, using the shaping and depth of the face scoop to direct flow as close to perpendicular to the boreline as possible, then making a moderate sized exit for the flow of that stream out through the waist vent. The more aggressive the forcing of that stream, the more boreline flow gets pushed to the side with the main cross-jet, increasing the volume which strikes the next baffle face for further disruption of flow.

As for the all-in-a-row versus criss-cross orienting of baffle vents; a friend with work experience in the field (ex-special forces) told me some time ago that the rule goes 180 degrees by turns for rimfire, with anything larger being all lined up. I'm not sure how this holds for the cartridge you're using, where a considerable number of users tend to favour clipped cones, or as Joe of CurtisTactical does, several K baffles followed by several clipped cones.

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delta9mda
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Re: K baffle alignment

Post by delta9mda » Fri Apr 29, 2016 1:08 am

mill the port parrallel to the bore, not at an angle. do it like the mfrs do it.
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T-Rex
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Re: K baffle alignment

Post by T-Rex » Fri Apr 29, 2016 7:36 am

As far as alignment goes, the majority are all 0*.
You can look over the years and some Mfr's go 90*, some 180*, some say this one 90* this one 270* etc.

As far as the milling from front or rear, you've gotta be kidding me in saying that less gas will flow into the coaxial volume if milled from the front.
The scoop is directing the gas there and you are helping it out.
I think fishman could orient the cutter a bit better (more around 45* and a smaller bit), but I do not see how a parallel cut, from the rear, allows better venting (works great, yes, but not the only way). Plenty of gas can slip right over the edge where you transition into the skirt's angle.

I do not believe, for a second, that because no major MFR does it that it doesn't work. There have to be a ton of new ideas, proven to work, that no major MFR uses. Not to mention the fact that there really aren't many K-Baffle, 30cal cans, marketed for 300blk. At least not enough to form a consensus of what features are solid gold. Remember the days of mouse holes and long waists? Convention would say, in those days, you need these features for suppression.

A good example of not going with convention is CurtisTactical's K-Baffles. He's taken a slightly different direction, uses less K's, and his videos sound great. His customers seem pretty happy as well.

I think with minimal tweaking you'll have a fantastic can. A built in muzzle brake design might be worth thinking about.
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curtistactical
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Re: K baffle alignment

Post by curtistactical » Fri Apr 29, 2016 9:39 pm

We cut our port in one shot from the rear. I have tried every port design imaginable and a cross port cut at 35 degrees from parallel to the bore using a ballnose cutter .01"-.02" under the bore diameter is the quietest, you can adjust breakthrough on the waist depending on caliber and whether it will be used sub or super sonic. The main reason you never see major manufacturers doing this is more of a manufacturing issue than a sound issue. I honestly have found k baffle orientation to have little effect on suppression, cones on the other hand need to be indexed if they are clipped,
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mikerla
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Re: K baffle alignment

Post by mikerla » Thu May 05, 2016 7:46 am

Noob Question

Can you explain "We cut our port in one shot from the rear."

Thanks

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