Airforce Knockoff or reseller?

[SpindleB]

If Snowpeak made these AF copies I feel better, because they have a good reputation to protect. 

The question is if that reputation is founded on steel air tanks, or have they made aluminum tanks for some time, without trouble?  If they are new at aluminum tanks, have they taken into account the unfriendly fatigue properties of aluminum, compared to steel.  Rhetorical questions, all.

7075 aluminum is twice as strong as 6061, but whether the design is "good" depends on the details.  I don't know the details of the bullpup mentioned, so can't comment.

The reason why I brought this up is because your face is against the tank when you shoot this AF PCP copy.  I would rather lose a finger tip than an eye...

I've been waiting years for any of these bottles to explode. But the reason I never hear of one exploding is because that isn't a failure mode. They would only explode If the vessel were placed under extreme duress. If they were to fail for manufacturing defect or corrosion it would just crack at the location and leak.Most likely at fill. Since that is maximum pressure when combined with compression heating.

[avator]

Yeah... I ain't freaking out. It's not like I have a flight scheduled on a commercial airline or anything..    

[Back_Roads]

 I have been using those bottles for a few years now, so far my head is still attached. I stick to the 3650 fills or less.

[splitbeing]

How's the pressure gauage on these?  I am questioning the pressure gauge on the P-Rifle, but I also don't trust my hand pump gauge to be truer.

[Back_Roads]

How's the pressure gauge on these?  I am questioning the pressure gauge on the P-Rifle, but I also don't trust my hand pump gauge to be truer.

Mine have been consistent with the gauges on my other filling devices.

[splitbeing]

Thanks, James.

I was expecting more shots from the P-Rifle and the reg to not be set so high.  But then again, Ikm still testing and am not sure I have the numbers right in my head. I think it dropped off the reg around 175 bar, but memory is a funny thing. Will know better when it drops off next time.

[subscriber]

I've been waiting years for any of these bottles to explode. But the reason I never hear of one exploding is because that isn't a failure mode.

The first question is the definition of "these bottles".  If you are referring to the filament wound gas bottles, they are amazingly robust; leaking rather than rupturing when abused - as can be seen in the video below.  What they would do if you pressurized them to 3+ there rated pressure is another question...

All metal bottles or tanks are not the same as filament wound bottles.  Steel air tanks that have not been abused or suffered corrosion "last forever".   Aluminum gas bottles need a higher factor of safety to offset their poorer fatigue life, compared to steel.

There are aluminum PCP air reservoirs that have exploded, generating a  consternation in the airgun community.  At least with respect to, "that is impossible" being countered by, "yet it happened" - as can be seen by the link directly below.  That thread is  long, but asks some very good questions about light weight air reservoirs mounted close to your face in a PCP.  One question remains; will we ever hear the full story?:  www.airgunnation.com/threads/leshiy-2-explodes.1284424/





It seems reasonable that a metal tank would let go at peak pressure, so probably during filling, but sometimes cracks are not yet all the way through the cylinder wall.  The firing event reduces the tank pressure a little, but firing it is like striking the tank with a screwdriver handle.  That little wrap can cause a crack to propagate, and for the tank to unzip spectacularly.  The energy stored in compressible gas is very large, compared to using incompressible fluid, which is why the latter is used for testing pressure vessels. 

The video below is of destructive testing of steel scuba tanks.  Using air rather than water or oil, yields a spectacularly abrupt release of energy:

[Back_Roads]

Thanks, James.

I was expecting more shots from the P-Rifle and the reg to not be set so high.  But then again, Ikm still testing and am not sure I have the numbers right in my head. I think it dropped off the reg around 175 bar, but memory is a funny thing. Will know better when it drops off next time.

My reg is at 15 MPA I may up that if I decide to use slugs on the heavy side. I have not really kept track of shot count, I get close to 40 for sure, I would be happy with 20 if I decide to put the gas to the slugs.

[avator]

P-Force.
As seen below the bottle is 350cc and the Huben Cricket plenum is 19.5cc.
I fill to 3600 psi as recommended and the reg is set to 14 -15 MPa (hard to read that tiny gauge)
I get 67 (on the run) shots with 14 fps spread But I'm sure I can tighten that up a bit with some HS adjustment.
30 FPE with an 18.1gr JTS pellet.

[splitbeing]

Steve on the bullpup thread noted his reg is also around 150 bar, same as the p-force. I would expect the p-rifle to also be around 150 bar.  I had it in my head as 150 where it fell off, but then it seemed to fall off at 175 last time I shot a fill.  I dont think hammer adjustment would affect the drop off point that much.  Looking forward to seeing where it falls off this next time. Memory is a funny thing.

Steve is getting 30 fpe as well with 21gr baracudas.

[rkrr20307@comcast.net]

The pressure gage on my P-RIFLE matches the gage on mt  GX CS4 pump.

[splitbeing]

The pressure gage on my P-RIFLE matches the gage on mt  GX CS4 pump.

Thanks, Richard.  What's your p-rifle reg set point/where does it fall off?

[Papa T]

My P-Rifle matched gage on my RovAir as I filled. Haven't checked it against my hand pump, but of the two I trust the rovair more.

[rkrr20307@comcast.net]

@splitbeing--- Dont know yet only shot a couple mags been fitting flu and in bed. Hopefully weather will change and can get some trigger time this weekend. In the video looks like 3 mags is about all on reg.

[splitbeing]

Thanks, Terry.

Richard, the Nibbs video he has the hammer setting flush/stock.  He didn't even get three mags on reg, but was close. I have been in search of the sweet spot.  At present, I am 30 shots in with all the shots around 873 fps, give or take 5 fps.  My hope is to get 40 shots on reg. 

[rkrr20307@comcast.net]

Sounds like you are on the right track. Keep us posted

[splitbeing]

At 873 plus or minus 5 fps with ftts I got 35 shots on reg. After that, it dropped off.  I got 44 shots total with a less than 20 fps ES (it was 17 or thereabout, next shot took it to 21).

I noticed when the hammer was flush and I first shot it, the first shot was higher than the subsequent shots (if memory serves).  It was pretty hot up there in 900s. After decreasing the hammer spring force to 850ish I noticed the first shot was lower in fps than subsequent shots. Same first shot phenomenon (ie lower) with an 873ish setting. 

Going to follow a hunch and increase the hammer tension to get around 900 fps and see first shot is higher, lower, or close to the speed of the subsequent shots. Might that be a trail to follow to the sweet spot (of shot count and power)?

[kylere1104]

Maybe it'll encourage airforce to keep innovating

[cosmic]

P-Force.. 3400 psi, regulator at 150bar or (15 mpa) ..

  JTS Dead Center 16.08gr. around 920 fps.. Power wheel set to one.. (Center the screw on the last tick mark closest to the breech..)
  Olympia slugs, Don't know if it to large or to long 25 gr.  755fps, One +12 (Center the screw on the last tick mark closest to the breech +12 on the dial)   (Need to slug the barrel)
  AVS .2193 22gr. dish base..  830 fps,  1.0 on power wheel... (Last tick mark, closest to the breech, center the screw..) I also have a super-well that I am trying... I will let you know.

[avator]

I'm a bit confused... which direction increases hammer strike... towards the muzzle or towards the breech?
When I got my gun it was set all the way towards the muzzle... bottomed out. I had to move it back to the 3rd hash from the muzzle to get the gun to fire.