2031 FPS on air . Latest shot, 2162 FPS

[match]

And I realize that 2162 is too high of a velocity for lead bullets (supposedly) because the rifling will strip off the bullet, ...

That depends on the alloy used and a few other things.

I have shot cast lead at 2600 fps in a 30-06 without issues.

John,
Thanks for letting me know.  You hear so many conflicting stories, it is always a pleasure to hear from someone who as actually "done it."
Lloyd

You do have to be careful because you can easily lead the barrel if your alloy, lube or sizing is off.

I never tried the coatings.

[MicErs]

With respect to lead bullets and operational velocities.  The problem with pure lead is that it strips into the rifling at velocities over about 1500 fps. The earlier solution to that was paper patching or pillow ticking or leather patching with lead balls.  That gets the pure lead bullet to about 1750 or 1800 fps where air pressure alone starts to flatten the ball as it travels down range thus decreasing the accuracy.  The next step in the evolution of lead projectiles was adding a bit of tin.  The amount depended upon how hard you wanted the bullet and that depended upon what velocity you were trying to push the bullet.  I've never handloaded with tinned lead but my grandfather and uncles loaded their 30-30 rifles with it and generally shot around 2400 fps.  So full power deer loads are certainly possible in lead bullets which have a bit of tin added.  I think they were using 5% tin. Don't hold me to that.


You might consider machining a pellet out of Delrin for your experiments.  Should be lighter than aluminum by a pretty wide margin.
https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=delrin

[lloyd-ss]

OK, from what I am hearing, high velocity lead bullets are all about knowing the tricks, either by trial and error, or hopefully, by getting help from someone who is willing to share the tricks that they have learned. 
Thanks,
Lloyd

[MicErs]

OK, from what I am hearing, high velocity lead bullets are all about knowing the tricks, either by trial and error, or hopefully, by getting help from someone who is willing to share the tricks that they have learned. 
Thanks,
Lloyd

Here is a technical discussion by someone who knows far more about it than me.  http://www.lasc.us/Fryxell_Book_Chapter_3_alloySelectionMetallurgy.htm

[rsterne]

No rifling = no leading.... so I don't think Lloyd has to worry.... especially with his aluminum pellets.... *grin*....

WELL DONE LLOYD !!! .... Next stop, Mach 2.... 

Bob

[MicErs]

No rifling = no leading.... so I don't think Lloyd has to worry.... especially with his aluminum pellets.... *grin*....

WELL DONE LLOYD !!! .... Next stop, Mach 2.... 

Bob

I guess we got off topic a bit, sorry.  I still think a Delrin pellet would weigh about half the aluminum one and take the pressure.

[lloyd-ss]

Yes, the Delrin pellet would be great, but unfortunately, the pellet is a structural element in the set-up, held from the rear, and the o-ring actually pulls the pellet from the front.  I tried the Delrin initially and it pulled apart.  The lightest projectile in the .278 cal so far has been 6.1 gns, but I need to go quite a bit lighter to get more velocity.  More design work to do.
Lloyd

[MichaelM]

WOW!!!!!!!!!!

Michael, I plan on bringing this to the FunShoot in May.  I am looking for someone to catch the bullets, kind of along the lines of the guy in this video 


Know anyone who might be up for the challenge? 
Thanks,
Lloyd

hrmmm dunno about catching..... could try this though...

[MicErs]

Yes, the Delrin pellet would be great, but unfortunately, the pellet is a structural element in the set-up, held from the rear, and the o-ring actually pulls the pellet from the front.  I tried the Delrin initially and it pulled apart.  The lightest projectile in the .278 cal so far has been 6.1 gns, but I need to go quite a bit lighter to get more velocity.  More design work to do.
Lloyd

Um sorry.  Pellet is structural.  Maybe you could change that a bit but I get it.  It is hard.

[lloyd-ss]

WOW!!!!!!!!!!

Michael, I plan on bringing this to the FunShoot in May.  I am looking for someone to catch the bullets, kind of along the lines of the guy in this video 


Know anyone who might be up for the challenge? 
Thanks,
Lloyd

hrmmm dunno about catching..... could try this though...

Yowww!   That guy is serious business. 

[match]

... The next step in the evolution of lead projectiles was adding a bit of tin.  The amount depended upon how hard you wanted the bullet and that depended upon what velocity you were trying to push the bullet. ...

We (my Dad and I) used an alloy of lead, tin, antimony, and a little copper - the copper was due to how we recovered and recycled the lead. It was a hard alloy with a mirror smooth cast finish. We never measured the Brinell number so I cannot say how hard it was but I would guess around 15 (pure lead is around 5, 3% tin (30:1) alloy is around 9).

My practice load was 165gr @ 2400 fps out of my Model 70 30-06 - and we would push it to 2600 fps occasionally without issues.

[lloyd-ss]

Yes, the Delrin pellet would be great, but unfortunately, the pellet is a structural element in the set-up, held from the rear, and the o-ring actually pulls the pellet from the front.  I tried the Delrin initially and it pulled apart.  The lightest projectile in the .278 cal so far has been 6.1 gns, but I need to go quite a bit lighter to get more velocity.  More design work to do.
Lloyd

Um sorry.  Pellet is structural.  Maybe you could change that a bit but I get it.  It is hard.

You got me to rummaging around in my "plastic materials".  I normally keep everything well marked with exactly what material it is, but I did find a piece of unidentified composite that I think is G9 or G10 Garolite.  If it is, it has about 3 times the tensile and compression strength of Delrin, and the calcs show that it has the strength needed for the task.  It is 60% of the weight of aluminum, so the potential for even higher velocities is very good.
So even though the Delrin didn't work out, you got me to thinking, and sometimes that does the trick.
Lloyd

[Onebaddj]

Very impressive brother!

And mach 2 is 2250.66 fps by the way. So close! YOU CAN DO IT!

[MichaelM]

Yowww!   That guy is serious business. 

Isao Machii is a Superhuman........ should search a bunch of his other stuff.... he does far more impressive  things as well.....

[Aged]

Hi Lloyd.
I'm new to the GTA. I signed up because of your video that showed that those phenomenal velocities with air power were possible.
I was fascinated when I saw the drawing of your custom breach which was tapered (funnel like) toward the barrel chamber. I don't have any way to prove it, just this instinct that tells me it is important. Besides you wouldn't have built it that way unless you thought it was the way to go.
--Ed.

[lloyd-ss]

Hi Lloyd.
I'm new to the GTA. I signed up because of your video that showed that those phenomenal velocities with air power were possible.
I was fascinated when I saw the drawing of your custom breach which was tapered (funnel like) toward the barrel chamber. I don't have any way to prove it, just this instinct that tells me it is important. Besides you wouldn't have built it that way unless you thought it was the way to go.
--Ed.

Ed,
Glad to have you as a new member in the GTA.  Lots of good stuff here, no matter what your air interest or skill level.
Thanks for joing,
Lloyd

[Aged]

Thank you Lloyd,
Could you explain to me and other members why incorporated this cone shaped breach chamber?
--Ed.

[lloyd-ss]

Thank you Lloyd,
Could you explain to me and other members why incorporated this cone shaped breach chamber?
--Ed.

Ed, sure thing... intuition.  The single goal for this setup was to achieve as high a projectile velocity as possible.  The conical funnel feeding directly into the back of the projectile seemed to be the most logical way to get the maximum usable airflow into the barrel.  There have been discussions of other shapes, convergent-divergent cones to increase velocity, but I am not sold on those.  In an open system they can achieve higher flow velocity, but in a closed system maybe not.  Harder to make, too, especially for something that might not add any benefit. A parabolic shape might yield slightly higher flow in this case, but that would be hard to prove without a side by side test, which was not the goal. Someone else can do that.
Lloyd

[Bent]

Next step could be to have vacuum in the barrel...



4500 psi burst discs.... just thinking.. 

[rsterne]

We keep hearing about the vacuum in the barrel idea.... works great for ping-pong balls which are large in area and are being driven by very low pressure, where removing the 14.7 psi in front of the ball is the same as adding the same pressure behind it.... With what we are doing, adding 14.7 psi to 4500 is hardly worth the effort....Would you get a bit more velocity?.... yes but not in proportion to the amount of work involved, IMO.... I have heard Lloyd express the same opinion....

Bob