Makes you go Hmm..!

[MikeVV]

A question about controlling airflow around the moving pellet / slug ?

A little of my background in airflow - I've been porting automotive and motorcycle cylinder heads for more flow, for 45+ years. Had more than a few folks come back for more. This is to say, I have a little experience with airflow and how to gain it.

I know that some suppressors (the new Fat Boy, the Caiman's, maybe more) have a form of an air stripper in the end cap.

So...has anyone done any work in modifying the end cap on a shroud or suppressor with flat end caps, to add an air stripper, or a form of, like is on the new Fat Boy suppressor? 

I had / have a thought about making some sort of stripper (cone) and fasten it to the inside of the xxx suppressor or the end cap of the given rifles shroud. Then add a few breather holes in the outer can to let the air that's now changed directions, a way away from the pellet flight path.

Reason - I know (as some of you do) that air hitting a solid flat wall, that is 90° to the general direction to the airflow, is NOT going to follow any given path. It will hit the inside wall, and bounce around in all manor of directions, with some, a little, a lot (?) of it making its way back into the pellets flight path out.

So, I'm thinking that, what if you put an air stripper, of some design, on the back of the given suppressor wall, or shroud end cap (many different methods !), would this aid in the pellets accuracy, with a smooth pellet path, along with the airflow staying in line with the pellet / slug's flight path ?

Thoughts ?

OR...has this been looked into and I'm way off base ?



Mike

 

[dizzums]

no idea really .. id say the higher end outfits have done the work for you to ensure minimal interferance .. doubt you could improve it much without alot of testing designs and keeping things real precision .. however, a dedicated air stripper from mac1 on the shroud of my mrod does noticeably increase accuracy, mostly it seems to cut down on flyers ..

 

[Long_Gun_Dallas]

Yep. It helps, and you're not off base. By function, a moderator with tight baffel bore is essentially an air stripper. As for holes in a mod body, I find it's best to put them at the rear. In the first chamber where pressure is highest. This does help reduce overall report (muzzle pressure). As long as the holes are small, they won't make much noise at all. I have a tiny 2 chamber mod on my nova star (in one of the photos below) that incorperates this idea, and actually works very well (also in part due to the air stripper housed in the shroud behind it). I believe I ported the shroud as well in the same manner, but can't recall at the moment %100



I don't have a pic of my HW 50 on the inside, but has a cone baffle at the end of the shroud exit.

I put a 6.2mm bore flat stripper in the end of two of my Crown superlight .22 barrels. On the back side of the threaded cap. I think bore was something like 9mm? Now 6.2mm. Both surfaces simply cross-hatched and epoxied together. OD is exactly the ID of the shroud.

I have an air stripper that also acts as a tensioner on my nova star .22 LW 14.5" barrel. (just above scope, shroud is off, bare aluminum stripper peeking out of shroud)

The old FX barrels (with extendable shrouds) have air strippers built in. I have a 600mm .30 barrel like this for my Crown. As well as an air stripper + ST solid liner-less barrel from a mk1 impact (500mm .22) for my Crown, too.

My custom 1322 pcp also has a stipper + baffle stack.

 

[MikeVV]

Thanks "dizz" -

But no "Long Gun", a "flat" piece of material is not...at all doing what a real (the photo in the second post) striper would do. With a flat wall, as with most ALL suppressors and shroud end caps, just dissipates the air flow in an uncontroled manor. Whereas a "cone" will strip, or move the air in a very controlled manor away from the pellet flight path. A VERY different action than a flat 90 degree, to the flight path action.

I personally don't see a flat wall doing much of any benefit. Yes, while by the word, it does "strip" the air away from the pellet, but in a very uncontrolled manor. And in no way does it dissipate the uncontrolled air, that an very easily reconnect to the pellets flight path air stream...and mess with it (not using any four letter words !), as the pellet exits the shroud / suppressor, where to me...the air should be as smooth as possible, behind the pellet.

And yes, I understand and agree with "breather" holes being close to the muzzle, I also feel, especially in the high powered guns, some air holes would be a good thing near the "cone" stripper to help reduce the uncontroled airflow, within the suppressor / shroud, as it's moved away from the pellet flight path.

Time for some experiments ! I love experimenting, (and I don't use that...four letter word much !).



Mike

 

[Long_Gun_Dallas]

Think about it for a second. A mod uses baffles. Flat, cone, whatever. The baffles trap air behind the projectile, and reduce discharge volume, and pressure going into the next chamber if for only a moment. The majority of the air is getting trapped behind the projectile. All an air stipper is is a baffle with large vents behind/beside it. The factory FX ones are flat. My 1322 one is flat. My hatsan one is flat. These strippers divert a large portion of the discharge reaward into shroud volume or directly to atmosphere. The baffle strips air off of the projectile as it passes thru it. The way I see it, the controlled or uncontrolled manner is going to be determined by concentricity of the bore to barrel axis. Cone or flat or other. At either rate, the projectile is exiting forward of the expanding air, so the effect is the same. Gasses passing thru or exiting a mod of any baffle design is essentially the definition of controlled....! To quite an extreme degree.



Same fluid dynamics apply but on a smaller scale. Video is edited to start at relevant bit.









https://youtu.be/IAR4yTYslkk?t=163

 

[John "spysir" Blount]

If I have this right, personally do not call the end cap on a fatboy a "stripper", just a changeable for cal. gizmo which is nice & Beeman offered this in the '80's.

If shrouded (or plain barrel and looking for accuracy tuning) just obtain an actually air stripper. Likely wont need anything else. Keep the bore tolerance about 0.004 and maybe try the length of pellet and go from there. That way the vast majority of air IS redirected away from the pellet preventing turbulence. A stripper after a moderator is not "stripping" a thing. Stripping MAKES noise if it really redirecting air greatly.

Anyone who's used the old USFT "T-Brake" can tell you which way the air is going after muzzle.

I believe this is an Swift made inside shroud stripper

And trying to show the slot length-every pellet/rig would be different but Theboen Vanquish, stripper and 5+ inch hollow tube and oh so silent.

John