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PostPosted: Tue Apr 23, 2013 2:59 pm 
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Using low regulated pressure and a heavy hammer hit is VERY inefficient (you will be way up on the plateau).... You may get the velocity you want, but nowhere near as many shots as you could get with a bit higher pressure and the correct hammer strike for that pressure.... Conversely if you use a high pressure and a very light hammer hit, you will get excellent efficiency, but when you get to the setpoint the velocity will start to CLIMB and could easily go over the 20 FPE you are striving for.... I'm not just blowing smoke here when I say the correct way to do this is to try different hammer settings and draw a graph of the resulting velocity, even if you do it by hand on graph paper.... The ideal hammer setting will vary with the regulator setpoint.... The place to get the maximum shot count for a given FPE level is on the knee of the curve....

Bob

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PostPosted: Tue Apr 23, 2013 3:12 pm 
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To lighten the hammer i turn counter clockwise? Or does that make it heavier? I would think loosening would lighten but sounds like ccw makes it heavier?

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PostPosted: Tue Apr 23, 2013 4:10 pm 
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The adjusting screw on an AT44 is inside the hammer, and unscrewing it (CCW) gives less space for the spring, and hence INCREASES the preload.... Fully clockwise until it stops is the minimum preload....

Bob

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PostPosted: Tue Apr 23, 2013 7:02 pm 
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Thanks Bob, i understood it correctly.

Optimum is minimal preload and lowest regulator setting?

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PostPosted: Tue Apr 23, 2013 9:59 pm 
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Only if you are after low power and maximum shot count.... You have a goal in mind, right?.... to be as close to 20 FPE as possible with maximum shot count.... I would try and achieve that power level first (if possible) and see what the shot count is when you are on the knee of the curve at whatever regulator pressure you need to do that.... If you need more shots, then reduce the pressure a bit, find the knee of the new curve, and see if you now have enough shots.... Keep going until you find the balance between shot count and FPE you can live with....

Bob

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Airsonal;
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PostPosted: Wed Apr 24, 2013 1:18 am 
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Like Bob said, have lots of lead to shoot. Cause here comes the fun part. ha ha LOL Way to go Chewy. :lol:

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PostPosted: Wed Apr 24, 2013 2:47 pm 
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i don't mind experimenting - it's the pumping up an empty tube by hand that has me taking my time on this....i could get somewhere with it of course but i try to limit fills to 2 a night lol

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PostPosted: Thu Apr 25, 2013 10:58 am 
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RE your comment about pumping.... You don't need to fire a whole string at each hammer preload setting, just 2-3 shots to make sure the velocity is stable and take the average.... ie, I fire 2 shots and they are within 1% I just use the average fps, I don't bother with a 3rd.... Reset the preload, and repeat, until you work your way through the range of preload settings at that regulator setpoint, then draw the graph and determine where the knee of the velocity curve is.... If it looks pretty good for power, refill and shoot a string at that setting to determine shot count and efficiency....

If you're not happy with those results, THEN you have to drain the cylinder, reset the regulator pressure, and repeat.... If you need more power, increase the pressure.... If you have lots of power and need more shots, reduce it.... then repeat the above test....

Bob

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PostPosted: Tue May 07, 2013 5:26 am 
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So how much success are you having with the altoros reg? Have you gotten out, to play with the tuning?

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PostPosted: Tue May 07, 2013 9:00 am 
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Sitting at 880fps for 28 full power shots. Aiming for a hair under 800 for as many as possible. This has been worked out but the only real way to make your gun do it is do it yourself. Which I'm trying. Im on hold with reg changes until my air tank for filling arrives. Make it go so much smoother when filling is effortless. When i get it tweaked i will post the config. If i can get this perfect with the .22 i may nab a .177 for field target and use 10.4 grain pellets.

Right now i haven't had the gun out of the stock yet to change the hammer spring tension. When i do it will be just to ensure that it is at its softest possible to help conserve air.

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PostPosted: Wed May 08, 2013 6:11 pm 
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Turned the regulator way down and have the tank pressure at 100 bar. Waiting 5 then going to finish it off. Hand pumping of course!

See what this does. Then pop it out if the stock and see where the hammer spring setting is. Going to try all in for softest hit first. My best guess is 720ish fps. This may do if I can crank the hammer spring up and get it to 780 ish with 18 grain pellets. I would be most happy with that. 50 shot range would be nice.

I want to get some felt on there so I can kill the ping.
Action is smooth wont go in the action for now.
Gonna run a few patches down the barrel

Would like a thicker magazine pin but I can't do that on my own
Will eventually polish contact points on the action

Will post shooting results if they are any good

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PostPosted: Wed May 08, 2013 9:33 pm 
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Right on chewy not long from now your tank will be here and you'll be asking yourself why didn't you go this route sooner. Lol

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PostPosted: Thu May 09, 2013 8:27 am 
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Well whatever i did resulted in only 20 shots down to 110 bar and i couldn't get a single chrony reading last night :(

I could tell it was wasting air big time lots coming out the muzzle after the pellet had left.

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PostPosted: Thu May 09, 2013 10:17 am 
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Did you take the O-ring off the valve?.... If that's not it, it sounds like you have wayyyyyyyyyy too much hammer strike.... you want it full CLOCKWISE (ie screw it in) when viewed from the butt of the gun.... If that's still too much, you may have to clip the spring....

Bob

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Airsonal;
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Proud Member of the 2000+fps Club!


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PostPosted: Fri May 10, 2013 8:37 am 
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rsterne wrote:
Did you take the O-ring off the valve?.... If that's not it, it sounds like you have wayyyyyyyyyy too much hammer strike.... you want it full CLOCKWISE (ie screw it in) when viewed from the butt of the gun.... If that's still too much, you may have to clip the spring....

Bob


Yes O-ring is off. Haven't had the gun out of its stock yet so i really don't know where the hammer spring is set to. I was reading they come all the way in but maybe that isn't the case.

That will be what i do this evening. Figure that one out. And try to get a chrony reading at current regulator setting as well.

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